
==== Front
Biomicrofluidics
Biomicrofluidics
BIOMGB
Biomicrofluidics
1932-1058
AIP Publishing LLC

10.1063/5.0201465
5.0201465
BMF24-RV-00027
Review Articles
Poly(lactic-co-glycolic acid) nanoparticle fabrication, functionalization, and biological considerations for drug delivery
https://orcid.org/0009-0007-3640-2537
Marecki Eric K. 1,2
https://orcid.org/0000-0003-0078-6683
Oh Kwang W. 1,2
https://orcid.org/0000-0002-9201-3305
Knight Paul R. 3
https://orcid.org/0000-0001-8223-1870
Davidson Bruce A. 3a)

1 Department of Biomedical Engineering, The State University of New York at Buffalo, Buffalo, New York 14260, USA
2 SMALL (Sensors and MicroActuators Learning Lab), Department of Electrical Engineering, The State University of New York at Buffalo, Buffalo, New York 14260, USA
3 Department of Anesthesiology, The State University of New York at Buffalo, Buffalo, New York 14203, USA
a) Author to whom correspondence should be addressed: bdavidso@buffalo.edu
17 9 2024
9 2024
17 9 2024
18 5 05150330 1 2024
03 9 2024
© 2024 Author(s).
2024
Author(s)
https://creativecommons.org/licenses/by-nc-nd/4.0/ All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International (CC BY-NC-ND) license (https://creativecommons.org/licenses/by-nc-nd/4.0/).
Nanoparticles can be used for drug delivery and consist of many sizes and chemical compositions. They can accommodate a diverse population of drugs and can be made to target specific areas of the body. Fabrication methods generally follow either top-down or bottom-up manufacturing techniques, which have differing production controls, which determine nanoparticle characteristics including but not limited to size and encapsulation efficiency. Functionalizing these nanoparticles is done to add drugs, prevent aggregation, add positive charge, add targeting, etc. As the nanoparticles reach the target cells, cellular uptake occurs, drug is released, and the nanoparticle is broken down. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles have often been used for drug delivery applications as they have shown minimal toxicity, which has helped with US FDA approval. This review breaks down PLGA nanoparticle fabrication, functionalization, and biological considerations.

National Institutes of Health 10.13039/100000002 R41AI149954 National Institutes of Health 10.13039/100000002 R01HL151498 crossmark
==== Body
pmcI. INTRODUCTION

Poly(lactic-co-glycolic acid) (PLGA) nanoparticles have been used as a vessel for drug delivery for some time. Some examples of PLGA nanoparticles are included in Table I. PLGA is an established US FDA approved polymer used in many nanoparticle applications due to its high biocompatibility and biodegradability.1–3 Bare PLGA nanoparticles, however, will not do much inside of the body and so research has been done to functionalize these nanoparticles for various applications. With the newly targeted applications, researchers needed to consider new sizes, shapes, drugs, surface features, and biology, which are largely accompanied by new fabrication methods.

TABLE I. List of US FDA approved drugs that contain PLGA. Note the approval years, some older and some newer.

Drug name	Active ingredient	Company	Application	Year approved	
Lupron Depot	Leuprolide acetate	AbbVie Endocrine Inc	Advanced Prostatic cancer	1989	
Sandostatin LAR	Octreotide acetate	Novartis	Acromegaly, carcinoid tumors, Vasoactive intestinal peptide Tumors	1998	
Eligard	Leuprolide acetate	Tolmar Therapy	Advanced prostatic cancer	2002	
Risperdal Consta	Risperidone	Janssen Pharms	Schizophrenia, bipolar disorder	2007	
Bydureon	Exenatide synthetic	AstraZeneca AB	Type 2 diabetes Mellitus	2012	

Two major methods exist to fabricate nanoparticles: emulsification-solvent evaporation and precipitation. Each has its advantages and disadvantages, with emulsification-solvent evaporation being able to be more easily scaled up where precipitation can achieve higher encapsulation efficiencies. Precipitation also includes the popular microfluidic methods that report fine-tuning of nanoparticle size, charge, and encapsulation efficiency. PLGA nanoparticles can be functionalized by choosing what drug is being loaded and by modifying the nanoparticle surface. After the nanoparticles are in the body, researchers need to consider passive targeting, the efficiency of cellular uptake, the release profile of any carried drugs, and the degradation/clearance/toxicity.

This review aims to provide an overview of PLGA nanoparticles starting with their fabrication, then how they are popularly functionalized, and finally what factors are often considered once the nanoparticles interact with the body. A researcher can use the contents of this review to jumpstart their design of a PLGA nanoparticle for a new application.

II. PLGA NP FABRICATION METHODS

A. Emulsification-solvent evaporation (top-down)

Top-down manufacturing is a process where an item is made by breaking down larger items like chopping wood. In terms of PLGA nanoparticle synthesis, top-down refers to the breaking down of a bulk precursor to nanoparticles using some mechanical method. As seen in Fig. 1, one common method is emulsification-solvent evaporation, which consists of applying high shear force (i.e., sonication/ultrasonication) to a mixture of a small amount of PLGA dissolved in water-immiscible organic solvent and a large amount of surfactant dissolved in water and then evaporating out the organic solvent.4–10 Many examples of various single emulsion techniques have been explored with varying success.5,8–14 The initial mixture does not form any nanoparticles since the organic solvent is not miscible in water, and so pockets of PLGA in organic solvent float around in the water, unable to form nanoparticles until agitated in some way. Using sonication as the example shear force, once the probe sonicator is introduced, the energy introduced forces the water-immiscible organic solvent to mix with the water, thus exposing PLGA to water. Since PLGA is hydrophobic, it will clump together in water and form nanoparticles. In this sense, the nanoparticles formed have no layer or bilayer and are, instead, simply a collection of PLGA polymers in a ball. The size of the nanoparticles that form initially is large but continues to decrease as the sonication continues. While sonication causes the initial mixing and nanoparticle formation, it also breaks up the nanoparticles after they have been formed to allow them to reform, typically at a smaller size. When taken to a limiting amount of time, nanoparticles will be broken down and reformed to the same size, based on the sonicator strength, and the sonication is complete. The removal of the organic solvent via evaporation reduces the nanoparticle size and is necessary afterward because the organic solvent is harmful to the nanoparticle actions and toxicity. PLGA nanoparticle properties can be detected in numerous ways including but not limited to electron microscopy, Dynamic light scattering (DLS), AFM, and fluorescence detection.15

FIG. 1. Emulsification-solvent evaporation single emulsion process. Sonication used as an example method to apply high shear force.

Since this organic solvent is immiscible in water, some examples are triethylamine,16 dichloromethane (DCM),5–8,12–14,16–24 chloroform,9,16,25,26 diethyl ether,16 and ethyl acetate.11,16 Many considerations come into play when determining which organic solvent is right, but sometimes, the most important parameter for fabrication is the length of the evaporation step. Diethyl ether has the shortest evaporation step and so it would be chosen if time was the largest factor.27 The toxicity of the chosen organic solvent may also be a greater factor when going for US FDA approval as substances like chloroform are highly toxic and need to be 100% removed to be deemed safe and getting to 100% removal will inevitably increase either fabrication time or cost.

Described earlier was single emulsion, where hydrophobic drugs would be used, but double emulsion has also been demonstrated, which allows the use of hydrophilic drugs as shown in Fig. 2.6,7,17–26,28 Double emulsion literally means two emulsions and consists of adding a small amount of water to the organic solvent before the organic solvent is added to the bulk water. Hydrophilic drugs are dissolved in the small amount of water added to the organic solvent. This is better than just adding hydrophilic drugs to the bulk water as the encapsulation efficiency is higher since more drug is near the PLGA when the nanoparticles are forming. If you add hydrophilic drugs to the bulk water, then there is a higher chance the drug never reaches any PLGA and, thus, is never encapsulated.

FIG. 2. Double emulsion process. Sonication again used as an example method to apply high shear force.

B. Precipitation (bottom-up)

Bottom-up manufacturing refers to the building up of a larger item from smaller pieces like building a house. For PLGA nanoparticle synthesis, bottom-up means forming nanoparticles from single polymer strands of PLGA. This has been done by adding an organic solvent to water just as before in a process called precipitation (nanoprecipitation for nanoparticle formation, except this organic solvent is miscible with water).4,29–40 With light magnetic stirring, the two phases mix readily and form nanoparticles immediately.

The organic phase used here needs to be miscible in water, so some examples are acetone,16,30,31,33,35,37,39,40 acetonitrile,16 dimethyl sulfoxide (DMSO),16 and tetrahydrofuran (THF).16,32 Again, the choice would be based on several factors including evaporation time and toxicity.

To manufacture a significant amount of nanoparticles for clinical and commercial applications, the scale-up of the process is necessary. These methods need to overcome several obstacles including reproducibility, toxicity, and surface chemistry.41,42 Existing solutions use membrane extrusion,43,44 supercritical fluid technology,45 and spinning disk processing46 each with its own advantages and disadvantages.

An adaptation to the previously mentioned bulk methods is the use of microfluidics and hydrodynamic flow focusing (HFF).47–52 In the HFF technique, the two phases are prepared the same but are then injected into a micro-/nano-scale polydimethylsiloxane (PDMS) device, which is manufactured by a combination of UV lithography and PDMS molding steps, where the two phases meet. In this type of device, the organic phase is pinched on both sides by the water phase. As soon as the phases meet, diffusion begins resulting in nanoparticle formation. To control the size and encapsulation efficiency, one can adjust several parameters including each phase's flow rate, the flow rate ratio, the channel length, all concentrations, and the materials are used. An additional material consideration with microfluidic methods is the interaction between PDMS and PLGA. Since normal PDMS is hydrophobic, it attracts PLGA and, by extension, the PLGA nanoparticles, leading to aggregation in the channels and eventually clogging. Methods have been developed to prevent this aggregation/clogging such as using oxygen plasma to oxidize the surface of the channels, which makes the surface hydrophilic and, thus, repels PLGA and the formed nanoparticles. Another challenge with microfluidics is the scale-up of the process as the working volume, though advantageous for size control and encapsulation efficiency, also limits the throughput.53,54 For microfluidic devices, scale-up is necessary to increase the naturally low throughput and can be achieved by employing parallelization and switching from PDMS to another material as PDMS cannot handle the higher flow rates required for increased throughput.55–57 Since many microfluidic scale-ups require making a more complex device, increases in the manufacturing cost and/or time can be expected.

After nanoparticles are produced by any method, they need to be stored properly to maintain their stability. The method (i.e., aqueous, freezing, and lyophilized storage) and type of cryoprotectant (i.e., sucrose, trehalose, or mannitol) greatly affect stability with notably the only US FDA approved COVID-19 mRNA vaccines, which are made from lipid nanoparticles, being stored in freezing conditions with sucrose.4,58,59

Both fabrication methods can benefit greatly from various PLGA nanoparticle manipulation techniques. Bulk methods tend to employ ultracentrifugation,15,60,61 ultrafiltration,15,62 size exclusion chromatography,15,63 precipitation,15,64 or immunoaffinity techniques,15,65 which are used to separate, purify, and concentrate the PLGA nanoparticles. Microfluidic methods can employ either active or passive techniques. Active techniques include acoustic,15,66 electric,15,67 magnetic,15,68 and optical controls,15,69 whereas passive techniques include inertial microfluidics,15,70 deterministic lateral displacement,15,71 microfluidic filtration,15,72 pinched flow fractionation,15,73 and viscoelastic microfluidics.15,74 Both active and passive techniques aim to control particles with active methods tending to be more precise but having lower throughput and passive methods tending to be less precise but having higher throughput.15,75

III. PLGA NP FUNCTIONALIZATION

A. NP loading

Nanoparticles can hold and deliver many different types of drugs and other substances including but not limited to doxorubicin (cancer),19 paclitaxel (cancer),9,12,39,76 Vascular endothelial growth factor (VEGF) (regenerative medicine),77 and various nucleic acids (whatever they code for, numerous applications).21,26,39,59,78 Drug/substance choice plays a major role in the determining fabrication method and based on whether the drug/substance is soluble in water or not. Doxorubicin and nucleic acids, for example, are water-soluble, whereas paclitaxel and VEGF are not.

The water-soluble drugs and substances must be dissolved in water, so for the emulsification-solvent evaporation method, double emulsion must be used.19,21,26,39,59,78 Water-soluble drugs are, thus, in the first water phase before adding to the organic solvent phase and then the bulk water phase. If you dissolve the drug in the bulk water phase, the encapsulation efficiency will be very low as most drug will never see any PLGA, so there is a lowered chance the drug is encapsulated whereas if the drug is dissolved in the first water phase, then all the drug has the potential to see PLGA as it is all added to the organic solvent phase first. For the precipitation method, since the organic solvent and water dissolve readily, it is important to keep the volume lower to increase the encapsulation efficiency. The larger the working volume, the higher chance the drug never sees PLGA, and increasing the amount of organic solvent phase creates a new problem as more nanoparticles will then end up forming with no drug, which is harder to separate out at the end as they should all roughly be the same size. Therefore, a technique like the microfluidic HFF, as shown in Fig. 3, will lead to higher encapsulation efficiency since the working volume is much smaller than bulk mixing and the ratio of organic solvent to water can be carefully managed.

FIG. 3. Microfluidic 3DHFF nanoparticle fabrication steps. shRNA is dissolved in the outer aqueous phase and mixed with the organic phase where the channels meet. The water and acetonitrile go through solvent exchange on the barrier of the phases. After solvent exchange, some PLGA is now in a water-rich environment and so it self-assembles into a nanoparticle. Solvent exchange continues over the length of the channel wherever the aqueous phase meets the organic phase with the nanoparticles growing over the length of the channel. Adjusting the speeds of the channels and the ratio of speeds can tune the final size of the nanoparticles.

Drugs like paclitaxel and the cytokine VEGF on the other hand cannot be dissolved in water and, therefore, are dissolved in the organic solvent.9,12,39,76,77 This means that the simpler single emulsion technique can be used for the emulsification-solvent evaporation method. Water-insoluble drugs are in the organic solvent phase, which is added to the bulk water phase, so all the drug has a chance to be encapsulated. Since the drugs are dissolved in the organic phase, simple bulk nanoprecipitation can be used for the precipitation method. If the microfluidic HFF technique is desired, the organic solvent phase should be switched with the water phase, so the organic solvent phase is in the middle channel and is squeezed by water phases on both sides. This would keep the drug, which is in the organic solvent phase, in the center of the channel and, thus, able to see PLGA. If you kept the organic solvent phase on the outside, then the formed nanoparticles on the water boundary would be more likely to contain no drug. The microfluidic method is still attractive compared to the bulk method due to its better experimental control, smaller working volume, and finer parameter tuning.

B. Surface modifications

PLGA nanoparticles themselves are simply a ball of PLGA and so they do not necessarily have control of where they are delivered, their surface charge, and the potential for collisions with other PLGA nanoparticles, resulting in aggregations or increased size. PLGA nanoparticles can have their surface modified with the addition of many different types of molecules including various targeting ligands, chitosan, lipids, polyethylene glycol (PEG), and surfactants as listed in Table II.

TABLE II. List of surface modifications. Additional secondary functions and examples in the text.

Surface modification	Main function(s)	Example(s)	Reference(s)	
Ligands	Cell targeting	Antibodies	9, 79–110	
Biotin	
Bisphosphonates	
Folic acid	
Lectins	
Mannan	
Aptamers	
Peptides	
Sialic acid	
Transferrin	
Chitosan	Adds positive charge to NP Improves cellular uptake	Chitosan	6, 14, 20, 31, 111	
Lipids	Increase encapsulation efficiency	Phospholipid	59, 78, 112–118	
Assist cellular uptake	Cationic lipid	
Encourage endosomal escape	Anionic lipid	
Can be charged	Cholesterol	
PEG	NP shielding	PEG	8–10, 32, 35, 36, 78, 119	
Surfactants	NP stabilization	PVA	5–9, 11–13, 17–19, 21–23, 26, 28–30, 34–36, 40, 120	
Can be charged	Pluronics	
Polysorbates	
Poloxamers	
DMAB	

For PLGA nanoparticles to be effective, they must be delivered to the right cells in the body. Adding cell-targeting ligands via physical association or chemical conjugation allows the PLGA nanoparticle to be internalized by receptor-mediated endocytosis after ligand–receptor binding. Ligands can be added by either electrostatic interactions where a positively charged group attached to the ligand is attracted to the negatively charged PLGA surface or through hydrophobic interactions where a ligand attached to a hydrophobic chain is attracted to the hydrophobic PLGA surface.79 Chemically, a ligand can be attached by carbodiimide (carboxyl–amine reaction), maleimide (maleimide–thiol reaction), or click chemistry (alkyne–azide reaction).121,122 The most common ligands are antibodies that only interact with their specific surface antigen including anti-CD133 (gastric carcinoma cells),9,79,80 anti-Prostate-specific membrane antigen (PSMA) (prostate cancer cells),79,81 and anti-HER2 (ovarian and human breast cancer cells).79,82–84 Other ligands include biotin (cancer),79,85 bisphosphonates (bone-related conditions),79,86–88 folic acid (brain, breast, cervical, colorectal, epithelial, kidney, lung, and ovarian tumors),79,89 lectins (cancer),79,90–93 mannan (macrophages and dendritic cells),79,94 aptamers (designed against any cancer-related biomarker),79,95–98 peptides (cancer and atherosclerotic plaques),79,99–108 sialic acid (cancer, leukocytes, platelets, and endothelial cells),79,109 and transferrin (breast cancer, pancreatic cancer, lung cancer, and brain gliomas).79,110

Chitosan is a polycationic polymer made from chitin that has been used for numerous biomedical applications including being added on to existing nanoparticles and serving as the base polymer for nanoparticles. For PLGA nanoparticles, it is used to add a positive charge to the surface of the nanoparticles.6,14,20,31,111 A positive surface charge on nanoparticles allows the nanoparticle to uptake into the cell more readily as charged nanoparticles (positive and negative) show preferential uptake in cells with positive charged nanoparticles showing the highest.111,123,124 Chitosan can be added to the surface of PLGA nanoparticles through simple bulk mixing as the PLGA gives the nanoparticle a negative charge, which will attract the positively charged chitosan. Since chitosan is positively charged, any negatively charged drug that is in the bulk when it is added will be attracted to it. This could result in a negatively charged drug being entrapped onto the surface of the nanoparticle, as opposed to within the ball of PLGA. The release profile could then be negatively impacted and result in incorrect encapsulation efficiency reporting as the drug on the surface would be counted as the entrapped drug. This issue can be avoided by adding chitosan after nanoparticle formation so that no drug is in the bulk phase when the chitosan is added.

Many types of lipids have been added to PLGA nanoparticles to enable monodisperse fabrication, improve stability, increase encapsulation efficiency of nucleic acids, assist cellular uptake, and encourage endosomal escape of nucleic acids.59,78,112–118 Phospholipids are types of lipids that are comprised of a hydrophilic “head” group containing a phosphate group, two hydrophobic “tails” that are derived from fatty acids, and a glycerol molecule to link them together. This amphiphilic nature causes phospholipids to self-arrange into a layer when in a solution containing water and organic solvent, as is the case when fabricating PLGA nanoparticles. The hydrophilic head will orient toward the water with the hydrophobic tails orienting toward the organic solvent. When surrounding a droplet of organic solvent, these phospholipids will self-arrange into a monolayer around the organic solvent forming a micelle. This will surround anything in that organic solvent droplet, which is the ball of PLGA for PLGA nanoparticles. The incorporation of phospholipids, therefore, increases stability and circulation time. The addition of cationic lipids has been shown to increase the encapsulation efficiency of nucleic acids due to the positive charge on the lipid attracting the negatively charged nucleic acids.59,78,113,117,118 Adding cholesterol maintains membrane integrity by matching the molar ratio to endogenous membranes as well as decreases the number of surface-bound proteins and improves circulation time.

PEG is a polyether compound that is commonly added to PLGA nanoparticle surfaces to help the nanoparticle avoid the mononuclear phagocytic system (functions as a shielding group). In short, this allows the PLGA nanoparticle to avoid phagocytosis and, thus, reach the intended target location. PEG is a common choice as a shielding group as it is electrically neutral, has high hydrophilicity, and shows high spatial repulsion.8–10,32,35,36,78,119 PEG can be added via physical absorption (as part of a hydrophobic or charged group), covalent coupling (as part of a reactive group), or self-assembly (as part of a hydrophobic copolymer including lipids).119 PEG has also been shown to improve the nanoparticle stability through steric repulsion, decrease the encapsulation efficiency of hydrophilic drugs, increase the encapsulation efficiency of hydrophobic drugs, and be susceptible to the accelerated blood clearance, which is a phenomenon where the circulating half-life of PEGylated nanoparticles is shortened after a second injection of nanoparticles is introduced, theorized to be the result of the spleen producing and releasing anti-PEG antibodies after the first injection.59,78,112–117,119,125

Surfactants are compounds that decrease surface tension between two materials, acting as a stabilizing compound. Examples include various pluronics,8,30,40,120 polysorbates,36,120 and poloxamers,29,35,36,120 as well as the commonly used polyvinyl alcohol (PVA).5–7,9,12,13,17–19,21–23,26,28,34,40,120 For PLGA nanoparticles, a surfactant is added to seal the nanoparticles, so they do not grow or aggregate. They consist of a hydrophilic head and a hydrophobic tail so when they interact with a nanoparticle, the tails orient toward the PLGA, and the heads orient toward the water. This results in the creation of a monolayer around the ball of PLGA. They can be further classified as nonionic and ionic depending on the charge of the head. Different surfactants also maintain different sizes of nanoparticles by changing the contact angle. Surfactants can also play a role in delivery as they can allow the surrounded PLGA core to avoid phagocytosis when attempting to reach the target area. The surfactant didodecyldimethylammonium bromide (DMAB) is unique as it has an inherent positive charge, thus removing the need for chitosan or other additions that add positive charge to the nanoparticle.11

IV. PLGA NP BIOLOGICAL CONSIDERATIONS

When PLGA nanoparticles enter the body, there are several major factors to consider. These being passive targeting, efficiency of cellular uptake, the release profile of any carried drugs, and the degradation/clearance/toxicity of the nanoparticle as seen in Table III. Accounting for all these factors will allow any nanoparticle to perform its function while not harming the body in any way.

TABLE III. List of biological considerations. Additional secondary factors and examples in text.

Biological considerations	Main factor(s)	Affect(s)	
Passive targeting	Size	Where in the body NP uptake occurs	
Cellular uptake	Size	Whether or not cellular uptake occurs	
Shape	Rate pathway of cellular uptake	
Surface modifications	
Release profile	Attached vs entrapped drug size	Drug release pathway and timing	
Degradation and clearance	Shape	Circulation time, toxicity, and environmental effects	
Surface modifications	

Targeting can be controlled by adding surface modifications as mentioned above (active targeting), but targeting can also be done by controlling the size of the PLGA nanoparticle (passive targeting). There are cases where active targeting is undesirable such as to avoid creating a binding site barrier effect and to reduce toxicity.126–128 In these cases, size control becomes very important in determining where the nanoparticles will uptake. Generally, nanoparticles must be within the 10–200 nm range as nanoparticles less than 10 nm in diameter are rapidly eliminated by the kidneys and nanoparticles greater than 200 nm in diameter cause inflammation and phagocytic activity.129–132 Examples for specific cells are that sizes of 30–50 nm are desired when targeting pancreatic cancer cells, sizes of 40–60 nm are better for targeting breast cancer cells, sizes around 100 nm are optimal for targeting the gastrointestinal tract, and sizes around 120 for respiratory epithelium.129,133–135

Cellular uptake of PLGA nanoparticles can occur in a few ways depending on the size, shape, and surface modifications (including charge). Five common pathways for cellular uptake are phagocytosis, caveolin-mediated endocytosis, clathrin-mediated endocytosis, independent endocytosis, and macropinocytosis each being more likely for certain nanoparticle conformations.129,136 Phagocytosis of nanoparticles occurs for larger particles like those greater than 200 nm and is initiated by opsonization (adsorption of antibodies onto the nanoparticle surface), which is then recognized by phagocytes and internalized.132,137 Surface modification by adding PEG can act as a shield, essentially preventing opsonization and, therefore, phagocytosis.137 Caveolin-mediated endocytosis happens where caveolin is located on the cell membrane. Uptake forms a 50–80 nm size vesicle, which can escape lysosomal degradation.138 Clathrin-mediated endocytosis takes place where clathrin is located on the plasma membrane and creates vesicles with diameters of 100–150 nm but are more susceptible to lysosomal degradation.139,140

Independent endocytosis occurs in cells without clathrin and caveolae, and an example is folate-modified nanoparticles, which also might escape trafficking into lysosomes.141,142 Macropinocytosis is for large nanoparticles that are too big for caveolae- or clathrin-mediated endocytosis and consists of bulk fluid uptake of all particles and dissolved molecules in the extracellular fluid.143 Nanoparticle shape affects uptake at certain sizes. For nanoparticles greater than 100 nm in diameter, the order of highest uptake to lowest was rods, spheres, cylinders, and then cubes.144 For nanoparticles less than 100 nm in diameter, spheres showed the highest uptake.145,146 Using needle-shaped PLGA nanoparticles was attempted and showed increased uptake but with the increased risk of lysosome disruption leading to cell apoptosis.147 Although the size dictates the pathway, MacCuaig et al. have shown that active targeting (surface modification) has a much larger impact on uptake than passive targeting (size/shape control).134 As mentioned above, adding certain surface modifications improves cellular uptake like the addition of antibodies or peptides when targeting cancers or certain lipids when targeting specific areas of the body.134,148 Also from above, positively charged nanoparticles (through surface addition of chitosan) show preferential uptake as the cell membrane possesses a slight negative charge and, thus, there are some electrostatic attractions influencing cellular uptake.123,124,149,150

PLGA nanoparticles for delivery must consider the release profile after uptake into a cell. The desired speed at which the delivered drug is released is disease-dependent and so the nanoparticle should be tailored to each case. Generally for PLGA nanoparticles, the burst release of the drug is followed by a prolonged release as there is drug adsorbed on the surface, which releases quickly, and drug entrapped inside the core, which releases slowly.151–156 Smaller nanoparticles intuitively degrade faster and, thus, deliver their drug faster.157,158

After the PLGA nanoparticle delivers its drug, it must then degrade or otherwise clear from the body to limit its toxicity. PLGA can be rapidly cleared by the mononuclear phagocyte system (MPS) as PLGA nanoparticles can diffuse across the permeable vasculature in this system.159 Complete removal of PLGA nanoparticles has been shown to occur within 10 min of administration.160,161 Based on this, if you are targeting rapid release to a location that does not take too long to reach, then this time constraint is of no concern. If you are targeting a location that takes more time, then you will need to employ techniques, some described above, to avoid this rapid clearance. Another way to avoid the MPS while also improving circulation time is to incorporate a hydrophilic shell to your nanoparticle, although the trade-off is increased risk of aggregation and liposome destruction.119 Non-spherical nanoparticles show reduced immune clearance and improved blood circulation time compared to spherical nanoparticles.162,163 The use of certain lipids or PEG can activate the host immune response or be cleared quickly after first administration due to the production of anti-PEG antibodies in a phenomenon known as the accelerated blood clearance effect.117,119,164,165 To avoid this, biodegradable lipids can be used.166–170 Nanoparticles with charged lipids can avoid clearance by the MPS but are susceptible to aggregation in solutions of high ionic strength like blood, which can result in rapid removal from the blood stream.171,172 Nanoparticles made with stabilizing agents such as chitosan, PVA, and Poloxamer 188 showed limited toxicity.173 Additions of nonionic surfactants like Poloxamer 188 also embrace the stealth effect by which opsonization and, thus, phagocytosis is avoided.120

The use and disposal of PLGA nanoparticles inevitably releases some of them into the environment, leading to potentially negative effects if in a high enough concentration.174,175 They can enter the environment by photochemical transformation, oxidation and reduction, dissolution and precipitation, adsorption and desorption, combustion, biotransformation, and abrasion.176 Material flow analysis and environmental fate modeling detail when PLGA nanoparticle emissions are produced, where they are ultimately deposited, and what happens to them once they are released to the environment.175,177,178 Negative effects of environmental release include nuclei damage and oxidative stress in microorganisms, DNA folding, chromosomal aberrations, and oxidative stress in plants, liver inflammation, reproductive toxicity, and oxidative stress in animals, and shape-based toxicity and oxidative stress in humans.179–186

V. CONCLUSION

PLGA nanoparticle applications grow constantly due to its flexibility in adapting the original bare PLGA nanoparticle by considering new drugs, surface modifications, and biology, as well as the fabrication methods to make those adaptations possible. Continued efforts to expand the field to treat numerous diseases by delivering many new drugs maintain the relevance of research in this field.

The use of nucleic acids as the loaded drug opens the applications of these nanoparticles to almost anything as the design of the nucleic acid can target almost anything. Some challenges remain like the ability to load drugs efficiently and evenly into PLGA nanoparticles with high throughput, the potential to scale up the high throughput processes like microfluidics that have been shown to raise the encapsulation efficiency ceiling, and the means to properly target the nanoparticles so they only go to the target region and nowhere else. As researchers look toward these and other new applications, PLGA nanoparticle fabrication, functionalization, and biological considerations are necessary starting points.

ACKNOWLEDGMENTS

This study was supported by grants from the National Institutes of Health under Grant Nos. R01HL151498 (P. R.K. and B. A.D.) and R41AI149954 (B.A.D., Hilliard Kutscher, and Jonathan F. Lovell).

AUTHOR DECLARATIONS

Conflict of Interest

The authors have no conflicts to disclose.

Author Contributions

Eric K. Marecki: Conceptualization (equal); Writing – original draft (equal); Writing – review & editing (equal). Kwang W. Oh: Supervision (equal); Writing – review & editing (equal). Paul R. Knight: Supervision (equal); Writing – review & editing (equal). Bruce A. Davidson: Supervision (equal); Writing – review & editing (equal).

DATA AVAILABILITY

Data sharing is not applicable to this article as no new data were created or analyzed in this study.
==== Refs
REFERENCES

1. Y. Wang, B. Qin, G. Xia, and S. H. Choi, “FDA’s poly(lactic-co-glycolic acid) research program and regulatory outcomes,” AAPS J. 23 (4 ), 92 (2021). 10.1208/s12248-021-00611-y 34189655
2. J. M. Lü et al. , “Current advances in research and clinical applications of PLGA-based nanotechnology,” Expert Rev. Mol. Diagn. 9 (4 ), 325–341 (2009) (in English). 10.1586/erm.09.15 19435455
3. M. Alvi, A. Yaqoob, K. Rehman, S. M. Shoaib, and M. S. H. Akash, “PLGA-based nanoparticles for the treatment of cancer: Current strategies and perspectives,” AAPS Open 8 (1 ), 12 (2022). 10.1186/s41120-022-00060-7
4. K. Y. Hernández-Giottonini et al. , “PLGA nanoparticle preparations by emulsification and nanoprecipitation techniques: Effects of formulation parameters,” RSC Adv. 10 (8 ), 4218–4231 (2020). 10.1039/C9RA10857B 35495261
5. C. T. S. Turk, U. C. Oz, T. M. Serim, and C. Hascicek, “Formulation and optimization of nonionic surfactants emulsified nimesulide-loaded PLGA-based nanoparticles by design of experiments,” AAPS PharmSciTech. 15 (1 ), 161–176 (2014). 10.1208/s12249-013-0048-9 24222270
6. M. Wang et al. , “Preparation, characterization, and in vitro and in vivo investigation of chitosan-coated poly (d,l-lactide-co-glycolide) nanoparticles for intestinal delivery of exendin-4,” Int. J. Nanomed. 8 , 1141–1154 (2013) (in English). 10.2147/ijn.S41457
7. M. Chaturvedi, Y. Molino, B. Sreedhar, M. Khrestchatisky, and L. Kaczmarek, “Tissue inhibitor of matrix metalloproteinases-1 loaded poly(lactic-co-glycolic acid) nanoparticles for delivery across the blood-brain barrier,” Int. J. Nanomed. 9 , 575–588 (2014) (in English). 10.2147/IJN.S54750
8. P. Yin et al. , “Bufalin-loaded mPEG-PLGA-PLL-cRGD nanoparticles: Preparation, cellular uptake, tissue distribution, and anticancer activity,” Int. J. Nanomed. 7 , 3961–3969 (2012) (in English). 10.2147/ijn.S32063
9. S. K. Swaminathan, E. Roger, U. Toti, L. Niu, J. R. Ohlfest, and J. Panyam, “CD133-targeted paclitaxel delivery inhibits local tumor recurrence in a mouse model of breast cancer,” J. Controlled Release 171 (3 ), 280–287 (2013). 10.1016/j.jconrel.2013.07.014
10. P. Liu, Y. Sun, Q. Wang, Y. Sun, H. Li, and Y. Duan, “Intracellular trafficking and cellular uptake mechanism of mPEG-PLGA-PLL and mPEG-PLGA-PLL-Gal nanoparticles for targeted delivery to hepatomas,” Biomaterials 35 (2 ), 760–770 (2014). 10.1016/j.biomaterials.2013.10.020 24148242
11. A. Xu et al. , “A physical model for the size-dependent cellular uptake of nanoparticles modified with cationic surfactants,” Int. J. Nanomed. 7 , 3547–3554 (2012) (in English). 10.2147/ijn.S32188
12. C. Jin, L. Bai, H. Wu, W. Song, G. Guo, and K. Dou, “Cytotoxicity of paclitaxel incorporated in PLGA nanoparticles on hypoxic human tumor cells,” Pharm. Res. 26 (7 ), 1776–1784 (2009). 10.1007/s11095-009-9889-z 19384463
13. R. M. Mainardes and R. C. Evangelista, “PLGA nanoparticles containing praziquantel: Effect of formulation variables on size distribution,” Int. J. Pharm. 290 (1 ), 137–144 (2005). 10.1016/j.ijpharm.2004.11.027 15664139
14. T.-W. Chung, S.-S. Wang, and W.-J. Tsai, “Accelerating thrombolysis with chitosan-coated plasminogen activators encapsulated in poly-(lactide-co-glycolide) (PLGA) nanoparticles,” Biomaterials 29 (2 ), 228–237 (2008). 10.1016/j.biomaterials.2007.09.027 17953984
15. S. Hettiarachchi et al. , “Recent microfluidic advances in submicron to nanoparticle manipulation and separation,” Lab Chip 23 (5 ), 982–1010 (2023). 10.1039/D2LC00793B 36367456
16. See https://organicchemistrydata.org/solvents/ for “Common solvents used in organic chemistry: table of properties,” ACS Division of Organic Chemistry (accessed 2023).
17. S. J. Fairley et al. , “Chlamydia trachomatis recombinant MOMP encapsulated in PLGA nanoparticles triggers primarily T helper 1 cellular and antibody immune responses in mice: A desirable candidate nanovaccine,” Int. J. Nanomed. 8 , 2085–2099 (2013) (in English). 10.2147/ijn.S44155
18. N. Samadi et al. , “The effect of lauryl capping group on protein release and degradation of poly(d,l-lactic-co-glycolic acid) particles,” J. Controlled Release 172 (2 ), 436–443 (2013). 10.1016/j.jconrel.2013.05.034
19. F. Li, J. Sun, H. Zhu, X. Wen, C. Lin, and D. Shi, “Preparation and characterization novel polymer-coated magnetic nanoparticles as carriers for doxorubicin,” Colloids Surf., B 88 (1 ), 58–62 (2011). 10.1016/j.colsurfb.2011.06.003
20. Y. Wang, P. Li, and L. Kong, “Chitosan-modified PLGA nanoparticles with versatile surface for improved drug delivery,” AAPS PharmSciTech 14 (2 ), 585–592 (2013). 10.1208/s12249-013-9943-3 23463262
21. D. Cun, C. Foged, M. Yang, S. Frøkjær, and H. M. Nielsen, “Preparation and characterization of poly(dl-lactide-co-glycolide) nanoparticles for siRNA delivery,” Int. J. Pharm. 390 (1 ), 70–75 (2010). 10.1016/j.ijpharm.2009.10.023 19836438
22. M. Zaric et al. , “Skin dendritic cell targeting via microneedle arrays laden with antigen-encapsulated poly-d,l-lactide-co-glycolide nanoparticles induces efficient antitumor and antiviral immune responses,” ACS Nano 7 (3 ), 2042–2055 (2013). 10.1021/nn304235j 23373658
23. S. Sunoqrot, J. W. Bae, S.-E. Jin, R. M. Pearson, Y. Liu, and S. Hong, “Kinetically controlled cellular interactions of polymer−polymer and polymer−liposome nanohybrid systems,” Bioconjugate Chem. 22 (3 ), 466–474 (2011). 10.1021/bc100484t
24. S. Ribeiro, N. Hussain, and A. T. Florence, “Release of DNA from dendriplexes encapsulated in PLGA nanoparticles,” Int. J. Pharm. 298 (2 ), 354–360 (2005). 10.1016/j.ijpharm.2005.03.036 15979263
25. N. Rescignano et al. , “Protein encapsulation in biodegradable polymeric nanoparticles: Morphology, fluorescence behaviour and stem cell uptake,” Macromol. Biosci. 13 (9 ), 1204–1212 (2013). 10.1002/mabi.201300140 23776101
26. H. Cohen et al. , “Sustained delivery and expression of DNA encapsulated in polymeric nanoparticles,” Gene Ther. 7 (22 ), 1896–1905 (2000). 10.1038/sj.gt.3301318 11127577
27. See http://www.stenutz.eu/chem/evaporation.php?s=3 for “Evaporation rates” (accessed 2023).
28. C. Colonna, R. Dorati, B. Conti, P. Caliceti, and I. Genta, “Sub-unit vaccine against S. aureus-mediated infections: Set-up of nano-sized polymeric adjuvant,” Int. J. Pharm. 452 (1 ), 390–401 (2013). 10.1016/j.ijpharm.2013.05.037 23707885
29. C. P. Reis, N. Martinho, C. Rosado, A. S. Fernandes, and A. Roberto, “Design of polymeric nanoparticles and its applications as drug delivery systems for acne treatment,” Drug Dev. Ind. Pharm. 40 (3 ), 409–417 (2014). 10.3109/03639045.2013.767826 23480566
30. A. Paul, S. Das, J. Das, A. Samadder, and A. R. Khuda-Bukhsh, “Cytotoxicity and apoptotic signalling cascade induced by chelidonine-loaded PLGA nanoparticles in HepG2 cells in vitro and bioavailability of nano-chelidonine in mice in vivo,” Toxicol. Lett. 222 (1 ), 10–22 (2013). 10.1016/j.toxlet.2013.07.006 23850776
31. Z. H. Wang, Z. Y. Wang, C. S. Sun, C. Y. Wang, T. Y. Jiang, and S. L. Wang, “Trimethylated chitosan-conjugated PLGA nanoparticles for the delivery of drugs to the brain,” Biomaterials 31 (5 ), 908–915 (2010). 10.1016/j.biomaterials.2009.09.104 19853292
32. H. Shen, X. Hu, M. Szymusiak, Z. J. Wang, and Y. Liu, “Orally administered nanocurcumin to attenuate morphine tolerance: Comparison between negatively charged PLGA and partially and fully PEGylated nanoparticles,” Mol. Pharm. 10 (12 ), 4546–4551 (2013). 10.1021/mp400358z 24195658
33. W. Tao et al. , “Docetaxel-loaded nanoparticles based on star-shaped mannitol-core PLGA-TPGS diblock copolymer for breast cancer therapy,” Acta Biomater. 9 (11 ), 8910–8920 (2013). 10.1016/j.actbio.2013.06.034 23816645
34. H.-Y. Kwon, J.-Y. Lee, S.-W. Choi, Y. Jang, and J.-H. Kim, “Preparation of PLGA nanoparticles containing estrogen by emulsification–diffusion method,” Colloids Surf., A 182 (1 ), 123–130 (2001). 10.1016/S0927-7757(00)00825-6
35. E. Vega, M. A. Egea, A. C. Calpena, M. Espina, and M. L. García, “Role of hydroxypropyl-β-cyclodextrin on freeze-dried and gamma-irradiated PLGA and PLGA-PEG diblock copolymer nanospheres for ophthalmic flurbiprofen delivery,” Int. J. Nanomed. 7 , 1357–1371 (2012) (in English). 10.2147/IJN.S28481
36. Y.-C. Chen, W.-Y. Hsieh, W.-F. Lee, and D.-T. Zeng, “Effects of surface modification of PLGA-PEG-PLGA nanoparticles on loperamide delivery efficiency across the blood–brain barrier,” J. Biomater. Appl. 27 (7 ), 909–922 (2011). 10.1177/0885328211429495 22207601
37. S. S. Bhattacharyya et al. , “Poly (lactide-co-glycolide) acid nanoencapsulation of a synthetic coumarin: Cytotoxicity and bio-distribution in mice, in cancer cell line and interaction with calf thymus DNA as target,” Toxicol. Appl. Pharmacol. 253 (3 ), 270–281 (2011). 10.1016/j.taap.2011.04.010 21549736
38. H.-J. Jeon, Y.-I. Jeong, M.-K. Jang, Y.-H. Park, and J.-W. Nah, “Effect of solvent on the preparation of surfactant-free poly(dl-lactide-co-glycolide) nanoparticles and norfloxacin release characteristics,” Int. J. Pharm. 207 (1 ), 99–108 (2000). 10.1016/S0378-5173(00)00537-8 11036235
39. W. P. Su, F. Y. Cheng, D. B. Shieh, C. S. Yeh, and W. C. Su, “PLGA nanoparticles codeliver paclitaxel and Stat3 siRNA to overcome cellular resistance in lung cancer cells,” Int. J. Nanomed. 7 , 4269–4283 (2012) (in English). 10.2147/IJN.S33666
40. A. M. Paiva et al. , “Development of noncytotoxic PLGA nanoparticles to improve the effect of a new inhibitor of p53–MDM2 interaction,” Int. J. Pharm. 454 (1 ), 394–402 (2013). 10.1016/j.ijpharm.2013.07.017 23856033
41. Y. Herdiana, N. Wathoni, S. Shamsuddin, and M. Muchtaridi, “Scale-up polymeric-based nanoparticles drug delivery systems: Development and challenges,” OpenNano 7 , 100048 (2022). 10.1016/j.onano.2022.100048
42. X. Liu and H. Meng, “Consideration for the scale-up manufacture of nanotherapeutics—A critical step for technology transfer,” View 2 (5 ), 20200190 (2021). 10.1002/VIW.20200190
43. P. Guo, J. Huang, Y. Zhao, C. R. Martin, R. N. Zare, and M. A. Moses, “Nanomaterial preparation by extrusion through nanoporous membranes,” Small 14 (18 ), 1703493 (2018). 10.1002/smll.201703493
44. W. Xu et al. , “Generation of polymer nanocapsules via a membrane-extrusion emulsification approach,” Mater. Lett. 77 , 96–99 (2012). 10.1016/j.matlet.2012.03.004
45. P. Pathak, M. J. Meziani, T. Desai, and Y.-P. Sun, “Formation and stabilization of ibuprofen nanoparticles in supercritical fluid processing,” J. Supercrit. Fluids 37 (3 ), 279–286 (2006). 10.1016/j.supflu.2005.09.005
46. V. Hakke, S. Sonawane, S. Anandan, S. Sonawane, and M. Ashokkumar, “Process intensification approach using microreactors for synthesizing nanomaterials—A critical review,” Nanomaterials 11 (1 ), 98 (2021). 10.3390/nano11010098 33406661
47. M. Ghasemi Toudeshkchouei, P. Zahedi, and A. Shavandi, “Microfluidic-assisted preparation of 5-fluorouracil-loaded PLGA nanoparticles as a potential system for colorectal cancer therapy,” Materials 13 (7 ), 1483 (2020). 10.3390/ma13071483 32218241
48. A. Fabozzi et al. , “Design of functional nanoparticles by microfluidic platforms as advanced drug delivery systems for cancer therapy,” Lab Chip 23 (5 ), 1389–1409 (2023). 10.1039/D2LC00933A 36647782
49. N. Lababidi, V. Sigal, A. Koenneke, K. Schwarzkopf, A. Manz, and M. Schneider, “Microfluidics as tool to prepare size-tunable PLGA nanoparticles with high curcumin encapsulation for efficient mucus penetration,” Beilstein J. Nanotechnol. 10 , 2280–2293 (2019) (in English). 10.3762/bjnano.10.220 31807413
50. R. Donno et al. , “Nanomanufacturing through microfluidic-assisted nanoprecipitation: Advanced analytics and structure-activity relationships,” Int. J. Pharm. 534 (1 ), 97–107 (2017). 10.1016/j.ijpharm.2017.10.006 29017804
51. S. Rezvantalab and M. K. Moraveji, “Microfluidic assisted synthesis of PLGA drug delivery systems,” RSC Adv. 9 (4 ), 2055–2072 (2019). 10.1039/C8RA08972H 35516107
52. S. Gimondi et al. , “Microfluidic mixing system for precise PLGA-PEG nanoparticles size control,” Nanomed.: Nanotechnol. Biol. Med. 40 , 102482 (2022). 10.1016/j.nano.2021.102482
53. F. Danhier, E. Ansorena, J. M. Silva, R. Coco, A. L. Breton, and V. Préat, “PLGA-based nanoparticles: An overview of biomedical applications,” J. Controlled Release 161 (2 ), 505–522 (2012). 10.1016/j.jconrel.2012.01.043
54. E. Sah and H. Sah, “Recent trends in preparation of poly(lactide-co-glycolide) nanoparticles by mixing polymeric organic solution with antisolvent,” J. Nanomater. 2015 , 794601 (2015). 10.1155/2015/794601
55. l.-J. Pan et al. , “Controllable synthesis of nanocrystals in droplet reactors,” Lab Chip 18 (1 ), 41–56 (2018). 10.1039/C7LC00800G
56. H.-H. Jeong, V. R. Yelleswarapu, S. Yadavali, D. Issadore, and D. Lee, “Kilo-scale droplet generation in three-dimensional monolithic elastomer device (3D MED),” Lab Chip 15 (23 ), 4387–4392 (2015). 10.1039/C5LC01025J 26428950
57. A. M. Nightingale et al. , “A stable droplet reactor for high temperature nanocrystal synthesis,” Lab Chip 11 (7 ), 1221–1227 (2011). 10.1039/C0LC00507J 21180744
58. P. Zhao et al. , “Long-term storage of lipid-like nanoparticles for mRNA delivery,” Bioactive Mater. 5 (2 ), 358–363 (2020). 10.1016/j.bioactmat.2020.03.001
59. J. Kim, Y. Eygeris, M. Gupta, and G. Sahay, “Self-assembled mRNA vaccines,” Adv. Drug Delivery Rev. 170 , 83–112 (2021). 10.1016/j.addr.2020.12.014
60. P. Arosio, T. Müller, L. Mahadevan, and T. P. J. Knowles, “Density-gradient-free microfluidic centrifugation for analytical and preparative separation of nanoparticles,” Nano Lett. 14 (5 ), 2365–2371 (2014). 10.1021/nl404771g 24611748
61. M. A. Livshits et al. , “Isolation of exosomes by differential centrifugation: Theoretical analysis of a commonly used protocol,” Sci. Rep. 5 (1 ), 17319 (2015). 10.1038/srep17319 26616523
62. J. Lohwacharin and S. Takizawa, “Effects of nanoparticles on the ultrafiltration of surface water,” J. Membr. Sci. 326 (2 ), 354–362 (2009). 10.1016/j.memsci.2008.10.006
63. G.-T. Wei and F.-K. Liu, “Separation of nanometer gold particles by size exclusion chromatography,” J. Chromatogr., A 836 (2 ), 253–260 (1999). 10.1016/S0021-9673(99)00069-2
64. K. Y. Chung, J. M. Quek, S. H. Neo, and H. P. Too, “Polymer-based precipitation of extracellular vesicular miRNAs from serum improve gastric cancer miRNA biomarker performance,” J. Mol. Diagn. 22 (5 ), 610–618 (2020). 10.1016/j.jmoldx.2020.01.016 32151712
65. D. Brambilla et al. , “EV separation: Release of intact extracellular vesicles immunocaptured on magnetic particles,” Anal. Chem. 93 (13 ), 5476–5483 (2021) (in English). 10.1021/acs.analchem.0c05194 33769802
66. S. Zhao et al. , “A disposable acoustofluidic chip for nano/microparticle separation using unidirectional acoustic transducers,” Lab Chip 20 (7 ), 1298–1308 (2020). 10.1039/D0LC00106F 32195522
67. M. Dimaki, M. H. Olsen, N. Rozlosnik, and W. E. Svendsen, “Sub-100 nm nanoparticle upconcentration in flow by dielectrophoretic forces,” Micromachines 13 (6 ), 866 (2022) (in English). 10.3390/mi13060866 35744480
68. S. Khizar, H. Ben Halima, N. M. Ahmad, N. Zine, A. Errachid, and A. Elaissari, “Magnetic nanoparticles in microfluidic and sensing: From transport to detection,” Electrophoresis 41 (13–14 ), 1206–1224 (2020) (in English). 10.1002/elps.201900377 32347555
69. H. Zhao et al. , “Continuous optical sorting of nanoscale biomolecules in integrated microfluidic-nanophotonic chips,” Sens. Actuators, B 331 , 129428 (2021). 10.1016/j.snb.2020.129428
70. Q. Zhao, D. Yuan, J. Zhang, and W. Li, “A review of secondary flow in inertial microfluidics,” Micromachines 11 (5 ), 461 (2020). 10.3390/mi11050461 32354106
71. M. Al-Fandi, M. Al-Rousan, M. A. K. Jaradat, and L. Al-Ebbini, “New design for the separation of microorganisms using microfluidic deterministic lateral displacement,” Rob. Comput. Integ. Manuf. 27 (2 ), 237–244 (2011). 10.1016/j.rcim.2010.06.003
72. Y. Cheng, Y. Wang, Z. Ma, W. Wang, and X. Ye, “A bubble- and clogging-free microfluidic particle separation platform with multi-filtration,” Lab Chip 16 (23 ), 4517–4526 (2016). 10.1039/C6LC01113F 27792227
73. A. L. Vig and A. Kristensen, “Separation enhancement in pinched flow fractionation,” Appl. Phys. Lett. 93 (20 ), 203507 (2008). 10.1063/1.3028652
74. G. Romeo, G. D’Avino, F. Greco, P. A. Netti, and P. L. Maffettone, “Viscoelastic flow-focusing in microchannels: Scaling properties of the particle radial distributions,” Lab Chip 13 (14 ), 2802–2807 (2013). 10.1039/c3lc50257k 23670133
75. S. Yan et al. , “An integrated dielectrophoresis-active hydrophoretic microchip for continuous particle filtration and separation,” J. Micromech. Microeng. 25 (8 ), 084010 (2015). 10.1088/0960-1317/25/8/084010
76. A. M. Barbuti and Z. S. Chen, “Paclitaxel through the ages of anticancer therapy: Exploring its role in chemoresistance and radiation therapy,” Cancers 7 (4 ), 2360–2371 (2015) (in English). 10.3390/cancers7040897 26633515
77. Y. Oduk et al. , “VEGF nanoparticles repair the heart after myocardial infarction,” Am. J. Physiol. Heart Circ. Physiol. 314 (2 ), H278–H284 (2017). 10.1152/ajpheart.00471.2017 29101176
78. X. Hou, T. Zaks, R. Langer, and Y. Dong, “Lipid nanoparticles for mRNA delivery,” Nat. Rev. Mater. 6 (12 ), 1078–1094 (2021) (in English). 10.1038/s41578-021-00358-0 34394960
79. M. M. El-Hammadi and J. L. Arias, “Recent advances in the surface functionalization of PLGA-based nanomedicines,” Nanomaterials 12 (3 ), 354 (2022) (in English). 10.3390/nano12030354 35159698
80. l. Xin, H.-T. Zhang, W.-F. Yang, Y.-F. Li, and C. Liu, “Evaluation of METase-pemetrexed-loaded PEG–PLGA nanoparticles modified with anti-CD133–scFV for treatment of gastric carcinoma,” Biosci. Rep. 38 (1 ), BSR20171001 (2018). 10.1042/BSR20171001 29229675
81. W. Hariri, T. Sudha, D. J. Bharali, H. Cui, and S. A. Mousa, “Nano-targeted delivery of toremifene, an estrogen receptor-α blocker in prostate cancer,” Pharm. Res. 32 , 2764–2774 (2015). 10.1007/s11095-015-1662-x 25762087
82. R. Domínguez-Ríos et al. , “Cisplatin-loaded PLGA nanoparticles for HER2 targeted ovarian cancer therapy,” Colloids Surf., B 178 , 199–207 (2019). 10.1016/j.colsurfb.2019.03.011
83. X. Zhang et al. , “Trastuzumab-coated nanoparticles loaded with docetaxel for breast cancer therapy,” Dose-Response 17 (3 ), 1559325819872583 (2019). 10.1177/1559325819872583 31523204
84. Z. Zhou, A. Badkas, M. Stevenson, J.-Y. Lee, and Y.-K. Leung, “Herceptin conjugated PLGA-PHis-PEG pH sensitive nanoparticles for targeted and controlled drug delivery,” Int. J. Pharm. 487 (1–2 ), 81–90 (2015). 10.1016/j.ijpharm.2015.03.081 25865568
85. M. Mehdizadeh et al. , “Biotin decorated PLGA nanoparticles containing SN-38 designed for cancer therapy,” Artif. Cells, Nanomed., Biotechnol. 45 (3 ), 495–504 (2017). 10.1080/21691401.2016.1178130 27137460
86. E. Cenni et al. , “The effect of poly (d, l-lactide-co-glycolide)-alendronate conjugate nanoparticles on human osteoclast precursors,” J. Biomater. Sci., Polym. Ed. 23 (10 ), 1285–1300 (2012). 10.1163/092050611X580373 21781381
87. K. R. Chaudhari et al. , “Bone metastasis targeting: A novel approach to reach bone using zoledronate anchored PLGA nanoparticle as carrier system loaded with Docetaxel,” J. Controlled Release 158 (3 ), 470–478 (2012). 10.1016/j.jconrel.2011.11.020
88. J. Zhang et al. , “Development of drug loaded nanoparticles binding to hydroxyapatite based on a bisphosphonate modified nonionic surfactant,” J. Nanomater. 2015 (1 ), 393968 (2015). 10.1155/2015/393968
89. R. Pieroth, S. Paver, S. Day, and C. Lammersfeld, “Folate and its impact on cancer risk,” Curr. Nutr. Rep. 7 , 70–84 (2018). 10.1007/s13668-018-0237-y 30099693
90. M. L. Bruschi, “Lectins and nanostructured drug delivery systems,” Curr. Drug Delivery 16 (3 ), 268–269 (2019). 10.2174/1567201816666181122105548
91. J. Chen et al. , “Solanum tuberosum lectin-conjugated PLGA nanoparticles for nose-to-brain delivery: In vivo and in vitro evaluations,” J. Drug Targeting 20 (2 ), 174–184 (2012). 10.3109/1061186X.2011.622396
92. S. K. Jain, T. Haider, A. Kumar, and A. Jain, “Lectin-conjugated clarithromycin and acetohydroxamic acid-loaded PLGA nanoparticles: A novel approach for effective treatment of H. pylori,” AAPS PharmSciTech 17 , 1131–1140 (2016). 10.1208/s12249-015-0443-5 26566630
93. Z. Wen et al. , “Odorranalectin-conjugated nanoparticles: Preparation, brain delivery and pharmacodynamic study on Parkinson's disease following intranasal administration,” J. Controlled Release 151 (2 ), 131–138 (2011). 10.1016/j.jconrel.2011.02.022
94. G. Wu, F. Zhou, L. Ge, X. Liu, and F. Kong, “Novel mannan-PEG-PE modified bioadhesive PLGA nanoparticles for targeted gene delivery,” J. Nanomater., 2012, 1 , p. 981670, 2012. 10.1155/2012/981670
95. J. Kaur and K. Tikoo, “Ets1 identified as a novel molecular target of RNA aptamer selected against metastatic cells for targeted delivery of nano-formulation,” Oncogene 34 (41 ), 5216–5228 (2015). 10.1038/onc.2014.447 25639877
96. I. Monaco et al. , “Aptamer functionalization of nanosystems for glioblastoma targeting through the blood–brain barrier,” J. Med. Chem. 60 (10 ), 4510–4516 (2017). 10.1021/acs.jmedchem.7b00527 28471660
97. M. Ni et al. , “Poly (lactic-co-glycolic acid) nanoparticles conjugated with CD133 aptamers for targeted salinomycin delivery to CD133+ osteosarcoma cancer stem cells,” Int. J. Nanomed. 10 (1 ), 2537–2554 (2015).
98. G. Ravichandran and A. K. Rengan, “Aptamer-mediated nanotheranostics for cancer treatment: A review,” ACS Appl. Nano Mater. 3 (10 ), 9542–9559 (2020). 10.1021/acsanm.0c01785
99. M. Alipour et al. , “Recent progress in biomedical applications of RGD-based ligand: From precise cancer theranostics to biomaterial engineering: A systematic review,” J. Biomed. Mater. Res. A 108 (4 ), 839–850 (2020). 10.1002/jbm.a.36862 31854488
100. Y. Cui et al. , “Dual-target peptide-modified erythrocyte membrane-enveloped PLGA nanoparticles for the treatment of glioma,” Front. Oncol. 10 , 563938 (2020). 10.3389/fonc.2020.563938 33194638
101. N. Feiner-Gracia, A. Dols-Pérez, M. Royo, C. Solans, M. Garcia-Celma, and C. Fornaguera, “Cell penetrating peptide grafting of PLGA nanoparticles to enhance cell uptake,” Eur. Polym. J. 108 , 429–438 (2018). 10.1016/j.eurpolymj.2018.09.026
102. I. Gessner and I. Neundorf, “Nanoparticles modified with cell-penetrating peptides: Conjugation mechanisms, physicochemical properties, and application in cancer diagnosis and therapy,” Int. J. Mol. Sci. 21 (7 ), 2536 (2020). 10.3390/ijms21072536 32268473
103. R. Gonzalez-Pizarro et al. , “Ocular penetration of fluorometholone-loaded PEG-PLGA nanoparticles functionalized with cell-penetrating peptides,” Nanomedicine 14 (23 ), 3089–3104 (2019). 10.2217/nnm-2019-0201 31769335
104. G. P. Hoyos-Ceballos et al. , “PLGA-PEG-ANG-2 nanoparticles for blood–brain barrier crossing: Proof-of-concept study,” Pharmaceutics 12 (1 ), 72 (2020). 10.3390/pharmaceutics12010072 31963430
105. R. L. Manthe and S. Muro, “ICAM-1-targeted nanocarriers attenuate endothelial release of soluble ICAM-1, an inflammatory regulator,” Bioeng. Transl. Med. 2 (1 ), 109–119 (2017). 10.1002/btm2.10050 28713860
106. N. Mehrotra, S. Kharbanda, and H. Singh, “Peptide-based combination nanoformulations for cancer therapy,” Nanomedicine 15 (22 ), 2201–2217 (2020). 10.2217/nnm-2020-0220 32914691
107. X. Nie et al. , “SP94 peptide-functionalized PEG-PLGA nanoparticle loading with cryptotanshinone for targeting therapy of hepatocellular carcinoma,” AAPS PharmSciTech 21 , 1–11 (2020). 10.1208/s12249-019-1542-5
108. J. M. Rios De L. Rosa et al. , “Microfluidic-assisted preparation of RGD-decorated nanoparticles: Exploring integrin-facilitated uptake in cancer cell lines,” Sci. Rep. 10 (1 ), 14505 (2020). 10.1038/s41598-020-71396-x 32879363
109. C. Chittasupho, S.-X. Xie, A. Baoum, T. Yakovleva, T. J. Siahaan, and C. J. Berkland, “ICAM-1 targeting of doxorubicin-loaded PLGA nanoparticles to lung epithelial cells,” Eur. J. Pharm. Sci. 37 (2 ), 141–150 (2009). 10.1016/j.ejps.2009.02.008 19429421
110. H. Choudhury et al. , “Transferrin receptors-targeting nanocarriers for efficient targeted delivery and transcytosis of drugs into the brain tumors: A review of recent advancements and emerging trends,” Drug Delivery Transl. Res. 8 , 1545–1563 (2018). 10.1007/s13346-018-0552-2
111. I. Aranaz et al. , “Chitosan: An overview of Its properties and applications,” Polymers 13 (19 ), 3256 (2021). 10.3390/polym13193256 34641071
112. R. J. C. Bose, S.-H. Lee, and H. Park, “Lipid-based surface engineering of PLGA nanoparticles for drug and gene delivery applications,” Biomater. Res. 20 (1 ), 34 (2016). 10.1186/s40824-016-0081-3 27807476
113. B. Mandal et al., “Core–shell-type lipid–polymer hybrid nanoparticles as a drug delivery platform,” Nanomed. Nanotechnol. Biol. Med. 9 (4 ), 474–491 (2013). 10.1016/j.nano.2012.11.010
114. Q. Zhong et al. , “Optimization of DNA delivery by three classes of hybrid nanoparticle/DNA complexes,” J. Nanobiotechnol. 8 (1 ), 6 (2010). 10.1186/1477-3155-8-6
115. K. Hadinoto, A. Sundaresan, and W. S. Cheow, “Lipid–polymer hybrid nanoparticles as a new generation therapeutic delivery platform: A review,” Eur. J. Pharm. Biopharm. 85 (3 ), 427–443 (2013). 10.1016/j.ejpb.2013.07.002 23872180
116. C. Clawson, L. Ton, S. Aryal, V. Fu, S. Esener, and L. Zhang, “Synthesis and characterization of lipid–polymer hybrid nanoparticles with pH-triggered poly(ethylene glycol) shedding,” Langmuir 27 (17 ), 10556–10561 (2011). 10.1021/la202123e 21806013
117. C. Hald Albertsen, J. A. Kulkarni, D. Witzigmann, M. Lind, K. Petersson, and J. B. Simonsen, “The role of lipid components in lipid nanoparticles for vaccines and gene therapy,” Adv. Drug Delivery Rev. 188 , 114416 (2022). 10.1016/j.addr.2022.114416
118. E. Fröhlich, “The role of surface charge in cellular uptake and cytotoxicity of medical nanoparticles,” Int. J. Nanomed. 7 , 5577–5591 (2012) (in English). 10.2147/IJN.S36111
119. l. Shi et al. , “Effects of polyethylene glycol on the surface of nanoparticles for targeted drug delivery,” Nanoscale 13 (24 ), 10748–10764 (2021). 10.1039/D1NR02065J 34132312
120. T. Miyazawa, M. Itaya, G. C. Burdeos, K. Nakagawa, and T. Miyazawa, “A critical review of the use of surfactant-coated nanoparticles in nanomedicine and food nanotechnology,” Int. J. Nanomed. 16 , 3937–3999 (2021) (in English). 10.2147/IJN.S298606
121. A. Pucci, E. Locatelli, J. Ponti, C. Uboldi, V. Molinari, and M. Comes Franchini, “Click chemistry on the surface of PLGA-b-PEG polymeric nanoparticles: A novel targetable fluorescent imaging nanocarrier,” J. Nanopart. Res. 15 , 1–6 (2013). 10.1007/s11051-013-1818-8
122. M. Esfandyari-Manesh, M. Abdi, A. H. Talasaz, S. M. Ebrahimi, F. Atyabi, and R. Dinarvand, “S2P peptide-conjugated PLGA-Maleimide-PEG nanoparticles containing Imatinib for targeting drug delivery to atherosclerotic plaques,” Daru, J. Pharm. Sci. 28 , 131–138 (2020). 10.1007/s40199-019-00324-w
123. I. Slowing, B. G. Trewyn, and V. S. Y. Lin, “Effect of surface functionalization of MCM-41-type mesoporous silica nanoparticles on the endocytosis by human cancer cells,” J. Am. Chem. Soc. 128 (46 ), 14792–14793 (2006). 10.1021/ja0645943 17105274
124. D. L. J. Thorek and A. Tsourkas, “Size, charge and concentration dependent uptake of iron oxide particles by non-phagocytic cells,” Biomaterials 29 (26 ), 3583–3590 (2008). 10.1016/j.biomaterials.2008.05.015 18533252
125. J. V. Jokerst, T. Lobovkina, R. N. Zare, and S. S. Gambhir, “Nanoparticle PEGylation for imaging and therapy,” Nanomedicine 6 (4 ), 715–728 (2011). 10.2217/nnm.11.19 21718180
126. H. Lee, H. Fonge, B. Hoang, R. M. Reilly, and C. Allen, “The effects of particle size and molecular targeting on the intratumoral and subcellular distribution of polymeric nanoparticles,” Mol. Pharm. 7 (4 ), 1195–1208 (2010). 10.1021/mp100038h 20476759
127. H. Shmeeda, D. Tzemach, L. Mak, and A. Gabizon, “Her2-targeted pegylated liposomal doxorubicin: Retention of target-specific binding and cytotoxicity after in vivo passage,” J. Controlled Release 136 (2 ), 155–160 (2009). 10.1016/j.jconrel.2009.02.002
128. M. Wang and M. Thanou, “Targeting nanoparticles to cancer,” Pharmacol. Res. 62 (2 ), 90–99 (2010). 10.1016/j.phrs.2010.03.005 20380880
129. M. J. Mitchell, M. M. Billingsley, R. M. Haley, M. E. Wechsler, N. A. Peppas, and R. Langer, “Engineering precision nanoparticles for drug delivery,” Nat. Rev. Drug Discovery 20 (2 ), 101–124 (2021). 10.1038/s41573-020-0090-8 33277608
130. N. Hoshyar, S. Gray, H. Han, and G. Bao, “The effect of nanoparticle size on in vivo pharmacokinetics and cellular interaction,” Nanomedicine 11 (6 ), 673–692 (2016). 10.2217/nnm.16.5 27003448
131. G. Adamo, S. Campora, and G. Ghersi, “Functionalization of nanoparticles in specific targeting and mechanism release,” in Nanostructures for Novel Therapy, edited by D. Ficai and A. M. Grumezescu (Elsevier, 2017), Chap. III, pp. 57–80.
132. V. Schäfer et al. , “Phagocytosis of nanoparticles by human immunodeficiency virus (HlV)-infected macrophages: A possibility for antiviral drug targeting,” Pharm. Res. 9 (4 ), 541–546 (1992). 10.1023/A:1015852732512 1495900
133. H. Cabral et al. , “Accumulation of sub-100 nm polymeric micelles in poorly permeable tumours depends on size,” Nat. Nanotechnol. 6 (12 ), 815–823 (2011). 10.1038/nnano.2011.166 22020122
134. W. M. MacCuaig et al. , “Active targeting significantly outperforms nanoparticle size in facilitating tumor-specific uptake in orthotopic pancreatic cancer,” ACS Appl. Mater. Interfaces 13 (42 ), 49614–49630 (2021) (in English). 10.1021/acsami.1c09379 34653338
135. W. Jiang, B. Y. S. Kim, J. T. Rutka, and W. C. W. Chan, “Nanoparticle-mediated cellular response is size-dependent,” Nat. Nanotechnol. 3 (3 ), 145–150 (2008). 10.1038/nnano.2008.30 18654486
136. E. Blanco, H. Shen, and M. Ferrari, “Principles of nanoparticle design for overcoming biological barriers to drug delivery,” Nat. Biotechnol. 33 (9 ), 941–951 (2015). 10.1038/nbt.3330 26348965
137. A. Aderem and D. M. Underhill, “Mechanisms of phagocytosis in macrophages,” Annu. Rev. Immunol. 17 (1 ), 593–623 (1999). 10.1146/annurev.immunol.17.1.593 10358769
138. l. A. Carver and J. E. Schnitzer, “Caveolae: Mining little caves for new cancer targets,” Nat. Rev. Cancer 3 (8 ), 571–581 (2003). 10.1038/nrc1146 12894245
139. G. J. Doherty and H. T. McMahon, “Mechanisms of endocytosis,” Annu. Rev. Biochem. 78 (1 ), 857–902 (2009). 10.1146/annurev.biochem.78.081307.110540 19317650
140. M. Ehrlich et al. , “Endocytosis by random initiation and stabilization of clathrin-coated pits,” Cell 118 (5 ), 591–605 (2004). 10.1016/j.cell.2004.08.017 15339664
141. l. E. Kelemen, “The role of folate receptor α in cancer development, progression and treatment: Cause, consequence or innocent bystander?,” Int. J. Cancer 119 (2 ), 243–250 (2006). 10.1002/ijc.21712 16453285
142. Y. Lu and P. S. Low, “Folate-mediated delivery of macromolecular anticancer therapeutic agents,” Adv. Drug Delivery Rev. 64 , 342–352 (2012). 10.1016/j.addr.2012.09.020
143. J. P. Lim and P. A. Gleeson, “Macropinocytosis: An endocytic pathway for internalising large gulps,” Immunol. Cell Biol. 89 (8 ), 836–843 (2011). 10.1038/icb.2011.20 21423264
144. S. E. A. Gratton et al. , “The effect of particle design on cellular internalization pathways,” Proc. Natl. Acad. Sci. U.S.A. 105 (33 ), 11613–11618 (2008). 10.1073/pnas.0801763105 18697944
145. B. D. Chithrani, A. A. Ghazani, and W. C. W. Chan, “Determining the size and shape dependence of gold nanoparticle uptake into mammalian cells,” Nano Lett. 6 (4 ), 662–668 (2006). 10.1021/nl052396o 16608261
146. Y. Qiu et al. , “Surface chemistry and aspect ratio mediated cellular uptake of Au nanorods,” Biomaterials 31 (30 ), 7606–7619 (2010). 10.1016/j.biomaterials.2010.06.051 20656344
147. B. Zhang, P. Sai Lung, S. Zhao, Z. Chu, W. Chrzanowski, and Q. Li, “Shape dependent cytotoxicity of PLGA-PEG nanoparticles on human cells,” Sci. Rep. 7 (1 ), 7315 (2017). 10.1038/s41598-017-07588-9 28779154
148. C. Y. Hsu, P. W. Wang, A. Alalaiwe, Z. C. Lin, and J. Y. Fang, “Use of lipid nanocarriers to improve oral delivery of vitamins,” Nutrients 11 (1 ), 68 (2019) (in English). 10.3390/nu11010068 30609658
149. H. Jin, D. A. Heller, R. Sharma, and M. S. Strano, “Size-dependent cellular uptake and expulsion of single-walled carbon nanotubes: Single particle tracking and a generic uptake model for nanoparticles,” ACS Nano 3 (1 ), 149–158 (2009). 10.1021/nn800532m 19206261
150. J. Wang, S. Tian, R. A. Petros, M. E. Napier, and J. M. DeSimone, “The complex role of multivalency in nanoparticles targeting the transferrin receptor for cancer therapies,” J. Am. Chem. Soc. 132 (32 ), 11306–11313 (2010). 10.1021/ja1043177 20698697
151. C. J. Martínez Rivas et al. , “Nanoprecipitation process: From encapsulation to drug delivery,” Int. J. Pharm. 532 (1 ), 66–81 (2017). 10.1016/j.ijpharm.2017.08.064 28801107
152. S. Kumar, N. Dilbaghi, R. Rani, and G. Bhanjana, “Nanotechnology as emerging tool for enhancing solubility of poorly water-soluble drugs,” BioNanoScience 2 , 227 (2012). 10.1007/s12668-012-0060-7
153. M. T. Peracchia, R. Gref, Y. Minamitake, A. Domb, N. Lotan, and R. Langer, “PEG-coated nanospheres from amphiphilic diblock and multiblock copolymers: Investigation of their drug encapsulation and release characteristics,” J. Controlled Release 46 (3 ), 223–231 (1997). 10.1016/S0168-3659(96)01597-0
154. G. Yurtdaş Kırımlıoğlu, “Drug loading methods and drug release mechanisms of PLGA nanoparticles,” in Poly(Lactic-co-Glycolic Acid) (PLGA) Nanoparticles for Drug Delivery, edited by P. Kesharwani (Elsevier, 2023), Chap. III, pp. 55–86.
155. H. Safari, M. L. Felder, N. Kaczorowski, and O. Eniola-Adefeso, “Effect of the emulsion solvent evaporation technique cosolvent choice on the loading efficiency and release profile of anti-CD47 from PLGA nanospheres,” J. Pharm. Sci. 111 (9 ), 2525–2530 (2022). 10.1016/j.xphs.2022.04.007 35447106
156. M. Jelvehgari and S. H. Montazam, “Comparison of microencapsulation by emulsion-solvent extraction/evaporation technique using derivatives cellulose and acrylate-methacrylate copolymer as carriers,” Jundishapur J. Nat. Pharm. Prod. 7 (4 ), 144–152 (2012) (in English).24624173
157. Y. Xu, C. S. Kim, D. M. Saylor, and D. Koo, “Polymer degradation and drug delivery in PLGA-based drug–polymer applications: A review of experiments and theories,” J. Biomed. Mater. Res. B 105 (6 ), 1692–1716 (2017). 10.1002/jbm.b.33648
158. S. M. Bennett et al. , “The effect of particle size on the in vivo degradation of poly (d, l-lactide-co-glycolide)/α-tricalcium phosphate micro- and nanocomposites,” Acta Biomater. 45 , 340–348 (2016). 10.1016/j.actbio.2016.08.046 27567963
159. T. Bourguignon, A. A. Torrano, L. Houel-Renault, A. Machelart, P. Brodin, and R. Gref, “An original methodology to study polymeric nanoparticle-macrophage interactions: Nanoparticle tracking analysis in cell culture media and quantification of the internalized objects,” Int. J. Pharm. 610 , 121202 (2021). 10.1016/j.ijpharm.2021.121202 34666144
160. F. Esmaeili, M. H. Ghahremani, B. Esmaeili, M. R. Khoshayand, F. Atyabi, and R. Dinarvand, “PLGA nanoparticles of different surface properties: Preparation and evaluation of their body distribution,” Int. J. Pharm. 349 (1–2 ), 249–255 (2008). 10.1016/j.ijpharm.2007.07.038 17875373
161. J.-W. Yoo, E. Chambers, and S. Mitragotri, “Factors that control the circulation time of nanoparticles in blood: Challenges, solutions and future prospects,” Curr. Pharm. Des. 16 (21 ), 2298–2307 (2010). 10.2174/138161210791920496 20618151
162. M. Arnida, A. Ray, C. Peterson, and H. Ghandehari, “Geometry and surface characteristics of gold nanoparticles influence their biodistribution and uptake by macrophages,” Eur. J. Pharm. Biopharm. 77 (3 ), 417–423 (2011). 10.1016/j.ejpb.2010.11.010 21093587
163. A. Albanese, P. S. Tang, and W. C. Chan, “The effect of nanoparticle size, shape, and surface chemistry on biological systems,” Annu. Rev. Biomed. Eng. 14 , 1–16 (2012). 10.1146/annurev-bioeng-071811-150124 22524388
164. K. Knop, R. Hoogenboom, D. Fischer, and U. S. Schubert, “Poly(ethylene glycol) in drug delivery: Pros and cons as well as potential alternatives,” Angew. Chem., Int. Ed. 49 (36 ), 6288–6308 (2010). 10.1002/anie.200902672
165. A. S. Abu Lila, H. Kiwada, and T. Ishida, “The accelerated blood clearance (ABC) phenomenon: Clinical challenge and approaches to manage,” J. Controlled Release 172 (1 ), 38–47 (2013). 10.1016/j.jconrel.2013.07.026
166. M. A. Maier et al. , “Biodegradable lipids enabling rapidly eliminated lipid nanoparticles for systemic delivery of RNAi therapeutics,” Mol. Ther. 21 (8 ), 1570–1578 (2013). 10.1038/mt.2013.124 23799535
167. S. Sabnis et al. , “A novel amino lipid series for mRNA delivery: Improved endosomal escape and sustained pharmacology and safety in non-human primates,” Mol. Ther. 26 (6 ), 1509–1519 (2018). 10.1016/j.ymthe.2018.03.010 29653760
168. K. J. Hassett et al. , “Optimization of lipid nanoparticles for intramuscular administration of mRNA vaccines,” Mol. Ther. Nucl. Acids 15 , 1–11 (2019). 10.1016/j.omtn.2019.01.013
169. X. Zhang et al. , “Functionalized lipid-like nanoparticles for in vivo mRNA delivery and base editing,” Sci. Adv. 6 (34 ), eabc2315 (2020). 10.1126/sciadv.abc2315 32937374
170. X. Zhang et al. , “Biodegradable amino-ester nanomaterials for Cas9 mRNA delivery in vitro and in vivo,” ACS Appl. Mater. Interfaces 9 (30 ), 25481–25487 (2017). 10.1021/acsami.7b08163 28685575
171. J. S. Suk, Q. Xu, N. Kim, J. Hanes, and L. M. Ensign, “PEGylation as a strategy for improving nanoparticle-based drug and gene delivery,” Adv. Drug Delivery Rev. 99 , 28–51 (2016). 10.1016/j.addr.2015.09.012
172. J. Kim, H. J. Vaughan, C. G. Zamboni, J. C. Sunshine, and J. J. Green, “High-throughput evaluation of polymeric nanoparticles for tissue-targeted gene expression using barcoded plasmid DNA,” J. Controlled Release 337 , 105–116 (2021). 10.1016/j.jconrel.2021.05.047
173. S. Mura et al. , “Influence of surface charge on the potential toxicity of PLGA nanoparticles towards Calu-3 cells,” Int. J. Nanomed. 6 (null ), 2591–2605 (2011). 10.2147/IJN.S24552
174. G. Martínez et al. , “Environmental impact of nanoparticles’ application as an emerging technology: A review,” Materials 14 (1 ), 166 (2020) (in English). 10.3390/ma14010166 33396469
175. S. Rajkovic, N. A. Bornhöft, R. van der Weijden, B. Nowack, and V. Adam, “Dynamic probabilistic material flow analysis of engineered nanomaterials in European waste treatment systems,” Waste Manage. 113 , 118–131 (2020). 10.1016/j.wasman.2020.05.032
176. B. Nowack et al. , “Potential scenarios for nanomaterial release and subsequent alteration in the environment,” Environ. Toxicol. Chem. 31 (1 ), 50–59 (2012). 10.1002/etc.726 22038832
177. A. L. Dale, E. A. Casman, G. V. Lowry, J. R. Lead, E. Viparelli, and M. Baalousha, “Modeling nanomaterial environmental fate in aquatic systems,” Environ. Sci. Technol. 49 (5 ), 2587–2593 (2015). 10.1021/es505076w 25611674
178. B. Nowack, “Evaluation of environmental exposure models for engineered nanomaterials in a regulatory context,” NanoImpact 8 , 38–47 (2017). 10.1016/j.impact.2017.06.005
179. A. Elsaesser and C. V. Howard, “Toxicology of nanoparticles,” Adv. Drug Delivery Rev. 64 (2 ), 129–137 (2012). 10.1016/j.addr.2011.09.001
180. J. Lojk, J. Repas, P. Veranič, V. B. Bregar, and M. Pavlin, “Toxicity mechanisms of selected engineered nanoparticles on human neural cells in vitro,” Toxicology 432 , 152364 (2020). 10.1016/j.tox.2020.152364 31927068
181. M. J. Akhtar, M. Ahamed, H. Alhadlaq, and S. Alrokayan, “Toxicity mechanism of gadolinium oxide nanoparticles and gadolinium ions in human breast cancer cells,” Curr. Drug Metab. 20 (11 ), 907–917 (2019). 10.2174/1389200220666191105113754 31702485
182. M. Ghosh, M. Bandyopadhyay, and A. Mukherjee, “Genotoxicity of titanium dioxide (TiO2) nanoparticles at two trophic levels: Plant and human lymphocytes,” Chemosphere 81 (10 ), 1253–1262 (2010). 10.1016/j.chemosphere.2010.09.022 20884039
183. R. Lehner, C. Weder, A. Petri-Fink, and B. Rothen-Rutishauser, “Emergence of nanoplastic in the environment and possible impact on human health,” Environ. Sci. Technol. 53 (4 ), 1748–1765 (2019). 10.1021/acs.est.8b05512 30629421
184. J. Wang et al. , “Disruption of zebrafish (Danio rerio) reproduction upon chronic exposure to TiO2 nanoparticles,” Chemosphere 83 (4 ), 461–467 (2011). 10.1016/j.chemosphere.2010.12.069 21239038
185. K. P. Steckiewicz et al. , “Impact of gold nanoparticles shape on their cytotoxicity against human osteoblast and osteosarcoma in in vitro model. Evaluation of the safety of use and anti-cancer potential,” J. Mater. Sci.: Mater. Med. 30 (2 ), 22 (2019). 10.1007/s10856-019-6221-2 30747353
186. C. J. Labrador-Rached, R. T. Browning, L. K. Braydich-Stolle, and K. K. Comfort, “Toxicological implications of platinum nanoparticle exposure: Stimulation of intracellular stress, inflammatory response, and Akt signaling in vitro,” J. Toxicol. 2018 , 1367801 (2018). 10.1155/2018/1367801 30364051
