Fabrication Of Microparticles Research Articles

Design and batch fabrication of anisotropic microparticles toward small-scale robots using microfluidics: recent advances.

Small-scale robots with shape anisotropy have garnered significant scientific interest due to their enhanced mobility and precise control in recent years. Traditionally, these miniature robots are manufactured using established techniques such as molding, 3D printing, and microfabrication. However, the advent of microfluidics in recent years has emerged as a promising manufacturing technology, capitalizing on the precise and dynamic manipulation of fluids at the microscale to fabricate various complex-shaped anisotropic particles. This offers a versatile and controlled platform, enabling the efficient fabrication of small-scale robots with tailored morphologies and advanced functionalities from the microfluidic-derived anisotropic microparticles at high throughput. This review highlights the recent advances in the microfluidic fabrication of anisotropic microparticles and their potential applications in small-scale robots. In this review, the term 'small-scale robots' broadly encompasses micromotors endowed with capabilities for locomotion and manipulation. Firstly, the fundamental strategies for liquid template formation and the methodologies for generating anisotropic microparticles within the microfluidic system are briefly introduced. Subsequently, the functionality of shape-anisotropic particles in forming components for small-scale robots and actuation mechanisms are emphasized. Attention is then directed towards the diverse applications of these microparticle-derived microrobots in a variety of fields, including pollution remediation, cell microcarriers, drug delivery, and biofilm eradication. Finally, we discuss future directions for the fabrication and development of miniature robots from microfluidics, shedding light on the evolving landscape of this field.

High-yield fabrication of monodisperse multilayer nanofibrous microparticles for advanced oral drug delivery applications

Recent advances in the use of nano- and microparticles in drug delivery, cell therapy, and tissue engineering have led to increasing attention towards nanostructured microparticulate formulations for maximum benefit from both nano- and micron sized features. Scalable manufacturing of monodisperse nanostructured microparticles with tunable size, shape, content, and release rate remains a big challenge. Current technology, mainly comprises complex multi-step chemical procedures with limited control over these aspects. Here, we demonstrate a novel technique for high-yield fabrication of monodisperse monolayer and multilayer nanofibrous microparticles (MoNami and MuNaMi respectively). The fabrication procedure includes sequential electrospinning followed by micro-cutting at room temperature and transfer of particles for collection. The big advantage of the introduced technique is the potential to apply several polymer-drug combinations forming multilayer microparticles enjoying extracellular matrix (ECM)-mimicking architecture with tunable release profile. We demonstrate the fabrication and study the factors affecting the final three-dimensional structure. A model drug is encapsulated into a three-layer sheet (PLGA-pullulan-PLGA), and we demonstrate how the release profile changes from burst to sustain by simply cutting particles out of the electrospun sheet. We believe our fabrication method offers a unique and facile platform for realizing advanced microparticles for oral drug delivery applications.

Abstract 5745: Electrosprayed minocycline and temozolomide-loaded PLGA microparticles for the treatment of glioblastoma

Abstract Glioblastoma multiforme (GBM), the most common and aggressive form of malignant brain tumor, leads to poor prognoses with high rates of reoccurrence and low survival rates, therefore, it is vital to explore alternative treatments for GBM. Minocycline, a commonly used antibiotic and tetracycline derivative, has proven anti-angiogenic effects and the ability to inhibit tumor growth, making it an effective GBM treatment. Temozolomide is an alkylating antineoplastic agent and the current first-choice chemotherapy agent for GBM. Poly(lactic-co-glycolic acid) (PLGA) is widely used as a biomaterial for drug delivery due to its inert properties, great biocompatibility and versatility and has been approved by the FDA. Therefore, the objective of this project is to fabricate electrosprayed minocycline- and temozolomide-loaded PLGA microparticles with optimal morphology, drug loading, loading efficiency, and drug release kinetics for the treatment of GBM. The microparticles were fabricated by electrospraying vertically with a 2ml/hr flow rate, 14kV voltage, 20 cm distance for minocycline and a 10ml/hr flow rate, 10kV voltage, 10 cm distance for temozolomide with both collected on a copper/glass plate. The parameters that were investigated were the chamber humidity, duration of spraying, and the addition of polyethylene glycol (PEG), a hydrophilic polymer. To determine the microparticles’ morphology, bright-field microscopy and scanning electron microscopy (SEM) were used. The absorbance measurements at 350 and 327 nm were used to determine drug loading, loading efficiency, and release kinetics for minocycline and temozolomide, respectively. Microparticles with low chamber humidity and duration of spraying were more spherical, less aggregated and easier to collect for both drugs. The addition of PEG to minocycline-loaded microparticles led to higher drug loading and loading efficiency (4.02% ± 0.34, 64.30% ± 5.47 vs. 3.23% ± 0.29, 49.40% ± 4.49) as the PEG helps the solubilization of minocycline. Using acetonitrile instead of dichloromethane as the solvent, increased drug loading and loading efficiency (4.72% ± 0.76, 70.77 ± 11.43 vs. 2.37% ± 0.27, 35.62% ± 4.09) for temozolomide-loaded microparticles as more temozolomide can be solubilized in acetonitrile. Drug release kinetics demonstrated a burst release of minocycline in the first hour (65.46%). To decrease the burst release, the microparticles can be incorporated into a scaffold or depot. Overall, electrospraying is a promising method to fabricate drug loaded PLGA microparticles with high drug loading, loading efficiency, and right morphology and we determined optimal parameters to successfully fabricate electrosprayed drug loaded PLGA microparticles in the micron size range with high drug loading and loading efficiency compared to the often-used emulsion solvent extraction/evaporation for microparticle fabrication. Citation Format: Alma Rodriguez, Jaqueline Quintanilla, Juan Amieva, Marco A. Arriaga, Sean Nievera, Ivan Davila, Karen S. Martirosyan, Sue Anne Chew. Electrosprayed minocycline and temozolomide-loaded PLGA microparticles for the treatment of glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5745.

Magnetic field directed assembly of magnetic non-spherical microparticles

This study reports on the fabrication and assembly of anisotropic microparticles as versatile building blocks for directed magnetic assemblies. Although spherical microparticles have received extensive attention, the assembly of non-spherical magnetic microparticles remains underexplored. Herein, we present a fabrication approach that utilizes photolithography and soft lithography to create prism-shaped magnetic microparticles. In order to investigate their assembly, a switching rotating magnetic field was employed. To support our experimental findings, a numerical model which takes into account the magnetic dipole moments induced by the field of other particles was developed. This model helps in understanding the forces and torques governing particle behavior during assembly. Simulations were conducted using the numerical model to complement our experimental findings. In the two particle experiments, attractive magnetic interactions led to various configurations depending on initial positions. For three particles, a tip-to-tip configuration suggested closed or stable ring-like structures. Our work highlights the feasibility of producing highly responsive, non-spherical magnetic microparticles and their potential for assemblies. The versatile fabrication method, coupled with the added degree of freedom conferred by prismatic shapes, opens promising avenues for applications in biology and material science.

Solvent-Free Fabrication of Anisotropic Microparticles with Precise 3D Shape Control Using Dipping-Based Micromolding.

We present an innovative solvent-free micromolding technique for rapidly fabricating complex polymer microparticles with three-dimensional (3D) shapes utilizing a surface tension-induced dipping process. Our fabrication process involves loading a photocurable solution into micromolds through mold dipping. The loaded solution, induced by surface tension, undergoes spatial deformation upon mold removal caused by surface forces, ultimately acquiring an anisotropic shape before photopolymerization. Results show that the amount of photocurable solution loaded depends on the degree of capillary penetration, which can be adjusted by varying the dipping time and mold height. It enables the production of polymer particles with precisely controlled 3D shapes without diluting them with volatile organic solvents. Sequential micromolding enables the spatial stacking of the polymer domain through a bottom-up approach, facilitating the creation of complex multicompartmental microparticles with independently controlled compartments. Finally, we demonstrated the successful simultaneous conjugation of multiple model-fluorescent proteins through the biofunctionalization of microparticles, indicating functional stability and effective conjugation of hydrophilic molecules such as proteins. We also extend our capacity to create bicompartmental microparticles with distinct functionalities in each compartment, revealing spatially controlled functional structures. In summary, these findings demonstrate a straightforward, rapid, and reliable method for producing highly uniform complex particles with precise control over the 3D shape and compartmentalization, all accomplished without the use of organic solvents.

A Simple Non-Embedded Single Capillary Device for On-Demand Complex Emulsion Formation.

This study includes an examination of the design, fabrication, and experimentation of a rudimentary droplet generator. The device has potential applications in on-demand double and higher-order emulsions as well as tailored emulsions with numerous cores. The phenomenon of a pendant double droplet creation is observed when an inner phase is transported through a capillary, while a middle phase envelops the external surface of the capillary. This leads to the occurrence of a pinching-off process at the tip of the pulled capillary. Following this, the double droplet is introduced into a container that is filled with the outer phase. The present study examines the force equilibrium throughout the droplet break-up process and aims to forecast the final morphology of the droplets within the container by considering the impact of interfacial tension ratios. The shell thickness in a core-shell formation can be calculated based on the inner and middle phase flow rates as well as the middle droplet formation period. The present platform, which enables the simple production of double and higher emulsions, exhibits promising prospects for the controlled manufacturing of complex emulsions. This technology holds potential for various applications, including the experimental exploration of collision behavior or electro-hydrodynamics in emulsions as well as millimeter-size engineered microparticle fabrication.

Comparison of emulsion and spray methods for fabrication of rapamycin-loaded acetalated dextran microparticles

A comprehensive comparison between emulsion and spray methods for the fabrication of rapamycin-loaded Ace-DEX MPs, investigating physiochemical parameters, in vitro immunosuppressive efficacy, and in vivo trafficking.

Fabrication of Drug-Loaded Torus-Shaped Alginate Microparticles and Kinetic Analysis of Their Drug Release.

We fabricated drug-loaded, microsized, and torus-shaped alginate microparticles (TSMs) by vortex-ring freezing (VRF), utilizing vortex ring formation and ionic cross-linking. The equivalent outer diameter of the TSMs was ca. 200 μm. Several model drugs, such as doxorubicin, heparin, lysozyme, and several dextran derivatives, have been successfully loaded into TSMs. Because the TSMs were fragile due to the limitation of the process conditions of the VRF, drug-loaded TSMs were subsequently cross-linked via "post-cross-linking" with CaCl2, SrCl2, or BaCl2 to increase the cross-linking density of the alginate matrix, thereby enhancing the stability of dextran (Dex)-loaded TSMs (Dex-TSMs) and enabling the sustained release of natural Dex of 10, 70, or 150 kDa and cationic or anionic Dex at a physiological pH. The release kinetics of Dexs showed molecular weight and charge dependence; a relatively dense network of the alginate matrix of post-cross-linked TSMs resulted in the sustained release of Dexs with high molecular weights, heparin, and lysozyme for up to 7 days in the release test. Furthermore, the solute diffusivities of the dextran derivatives in the bulk alginate matrix were measured by using fluorescence correlation spectroscopy, which supported the release kinetics of TSMs. Drug-loaded TSMs have potential as drug carriers for biopharmaceuticals, such as proteins.

Scalable processing parameters to fabricate silicon elastomer microparticles using a blade-free planetary mixer with a thixotropic medium

The development of biomedical devices and soft robotics has spurred the utilization of silicone elastomers. Converting these polymers into particulates is increasingly important for their application to advanced materials and processes. However, the highly viscous nature of silicone resins, resulting from their long polymer chains, makes it challenging to fabricate them as particulates. Recently, a blade-free planetary mixer has been used to effectively emulsify viscous resins in a thixotropic medium. However, the particle fabrication process has not yet been examined to gain full control over the produced microparticles. This study presents key processing parameters for the fabrication of silicone elastomer microparticles in a sodium alginate medium using a blade-free planetary mixer. The experimental results show that stirring speed, stirring time, and medium concentration are the determining factors for controlling the particle size distribution. The variation in particle size by parameters exhibits differences depending on the viscous-to-elastic transition of the medium.

Fabrication and Characterization of Antibody-Loaded Cationic Porous PLGA Microparticles for Sustained Antibody Release.

Poly lactic-co-glycolic acid (PLGA) microparticles have been formulated to allow the sustained release of numerous drugs, including antibodies. It is well-known that antibodies are susceptible to chemical and physical stress; therefore, it is necessary to be loaded on PLGA microparticles under mild conditions. In the present study, we constructed cationic porous PLGA microparticles that could be electrostatically adsorbed with infliximab as a model antibody. Cationic porous PLGA microparticles were prepared using the double emulsion method by adding polyethyleneimine and ammonium bicarbonate. After antibody loading, surface pores closure was achieved by mild heating. The size of the optimized formulation was approximately 5 μm, exhibiting a positive charge. The loaded antibody was gradually released from the formulation over 56 days. Based on a tumor necrosis factor (TNF)-α inhibition assay, the released infliximab maintained its pharmacological activity. Collectively, we successfully loaded antibodies into PLGA microparticles while maintaining activity and demonstrating long-acting properties.

Fabrication of PEG-PLGA Microparticles with Tunable Sizes for Controlled Drug Release Application.

Polymeric microparticles of polyethyleneglycol-polylactic acid-co-glycolic acid (PEG-PLGA) are widely used as drug carriers for a variety of applications due to their unique characteristics. Although existing techniques for producing polymeric drug carriers offer the possibility of achieving greater production yield across a wide range of sizes, these methods are improbable to precisely tune particle size while upholding uniformity of particle size and morphology, ensuring consistent production yield, maintaining batch-to-batch reproducibility, and improving drug loading capacity. Herein, we developed a novel scalable method for the synthesis of tunable-sized microparticles with improved monodispersity and batch-to-batch reproducibility via the coaxial flow-phase separation technique. The study evaluated the effect of various process parameters on microparticle size and polydispersity, including polymer concentration, stirring rate, surfactant concentration, and the organic/aqueous phase flow rate and volume ratio. The results demonstrated that stirring rate and polymer concentration had the most significant impact on the mean particle size and distribution, whereas surfactant concentration had the most substantial impact on the morphology of particles. In addition to synthesizing microparticles of spherical morphology yielding particle sizes in the range of 5-50 µm across different formulations, we were able to also synthesize several microparticles exhibiting different morphologies and particle concentrations as a demonstration of the tunability and scalability of this method. Notably, by adjusting key determining process parameters, it was possible to achieve microparticle sizes in a comparable range (5-7 µm) for different formulations despite varying the concentration of polymer and volume of polymer solution in the organic phase by an order of magnitude. Finally, by the incorporation of fluorescent dyes as model hydrophilic and hydrophobic drugs, we further demonstrated how polymer amount influences drug loading capacity, encapsulation efficiency, and release kinetics of these microparticles of comparable sizes. Our study provides a framework for fabricating both hydrophobic and hydrophilic drug-loaded microparticles and elucidates the interplay between fabrication parameters and the physicochemical properties of microparticles, thereby offering an itinerary for expanding the applicability of this method for producing polymeric microparticles with desirable characteristics for specific drug delivery applications.

Fabrication of Versatile Janus Microparticles through Geometry and Surface Chemistry Control.

Amphiphilic Janus particles typically comprise two distinct hemispheres with spatially dispersed physicochemical properties. The anisotropic structure and physicochemical properties of Janus particles can be exploited for various applications. However, their preparation typically requires complex and sophisticated processes and expensive equipment to control the formation of different structures and chemical compositions. Herein, a simple synthetic approach for the facile fabrication of versatile Janus particles with efficient control of the Janus ratio and wettability based on particle fixation at a three-phase interface and photopolymerization is reported. Agarose gel and surfactant are used to control the surface-coated boundaries of the Janus particles through the equilibrium of a floating microparticle at the fluid interface. poly(propylene glycol) diacrylate or poly(N-isopropylacrylamide) coating on polystyrene-based microparticles allows easy control of the chemical functionality of the particle surfaces. Depending on the particle morphology and wettability, the interfacial behavior between two immiscible liquids can be adjusted, which allows the stabilization of Pickering emulsions that encapsulate independent oil droplets in water or vice versa. This facile approach has the potential to enable more efficient mass production of Janus particles and their use in various applications, such as biomedical and environmental engineering.

Recent Advances in Microfluidic Technologies for the Construction of Artificial Cells

AbstractArtificial cells are synthetic constructs that emulate natural cells, with potential applications in areas of energy science, environmental treatment, and the study of life's origins. Nevertheless, the construction of artificial cells is a formidable undertaking, given the intricate nature of natural cells in structures, functions, and working mechanisms. With precise control, high automation, and excellent uniformity, microfluidics has emerged as a promising approach for the construction of artificial cells. This review summarizes the latest microfluidic techniques utilized to construct artificial cells, ranging from simple droplets to sophisticated cell‐inspired systems. These include the generation of droplets, the production of vesicles (lipid‐based and polymer‐based vesicles), the fabrication of polymeric microparticles with various compartments, shapes, and microstructures, as well as the manufacture of sophisticated cell‐inspired systems. The characteristics of different methods for the construction of artificial cells are discussed in detail. Furthermore, the wide‐ranging applications of artificial cells are also showcased. Finally, contemporary obstacles and forthcoming advancements are discussed in the field of microfluidic‐based artificial cells. This review is supposed to stimulate research in the construction of more functional and natural‐like artificial cells, as well as works in the fields of material, biology, environment, medicine, and energy.

Microfluidic Platform for Microparticle Fabrication and Release of a Cathepsin Inhibitor.

Cathepsins are a family of cysteine proteases responsible for a variety of homeostatic functions throughout the body, including extracellular matrix remodeling, and have been implicated in a variety of degenerative diseases. However, clinical trials using systemic administration of cathepsin inhibitors have been abandoned due to side effects, so local delivery of cathepsin inhibitors may be advantageous. In these experiments, a novel microfluidic device platform was developed that can synthesize uniform, hydrolytically degradable microparticles from a combination of poly(ethylene glycol) diacrylate (PEGDA) and dithiothreitol (DTT). Of the formulations examined, the 10-polymer weight percentage 10 mM DTT formulation degraded after 77 days in vitro. A modified assay using the DQ Gelatin Fluorogenic Substrate was used to demonstrate sustained release and bioactivity of a cathepsin inhibitor (E-64) released from hydrogel microparticles over 2 weeks in vitro (up to ∼13 μg/mL released with up to ∼40% original level of inhibition remaining at day 14). Altogether, the technologies developed in this study will allow a small-molecule, broad cathepsin inhibitor E-64 to be released in a sustained manner for localized inhibition of cathepsins for a wide variety of diseases.

Controllable Monodisperse Amphiphilic Janus Microparticles

A facile microfluidic strategy has been successfully developed in this paper for the controllable fabrication of monodisperse amphiphilic Janus microparticles. The fabrication of such amphiphilic Janus microparticles is simply achieved by online UV curing of monodisperse Janus droplet templates that are prepared from microfluidics together with initial fast phase separation induced by co-solvent diffusion and sequential dewetting triggered by interfacial energy. Benefitting from the superiorities of droplet microfluidics, the morphologies of Janus microparticles can be flexibly and precisely controlled by adjusting the flowrates of fluids and the compositions of dispersed phase. Meanwhile, the functionalization of Janus microparticles can be easily realized by introducing certain elements into the dispersed phase to rationally design the bulbs with diverse advanced functions. We also demonstrate the universality of the proposed strategy through the fabrication of monodisperse Janus microparticles with one bulb consisting of hydrophobic poly(ethoxylated trimethylolpropane triacrylate) and another bulb consisting of a hydrophilic hydrogel such as poly(N-isopropyl acrylamide), poly(N-vinylcaprolactam), or polyacrylamide. The thermoresponsive hydrophilic/hydrophobic phase transition property of the poly(N-isopropyl acrylamide) bulb enables the Janus microparticles to be used as functional colloidal surfactants for adjusting the stability/instability of oil–water interface. Our strategy provides a versatile and efficient way to fabricate monodisperse amphiphilic Janus microparticles with controlled structures and diverse functions, which show great application potentials in plenty of fields.

Fabrication of heat-stable composite microparticles from egg and whey proteins and their application in emulsion stabilization

This study investigated the feasibility of egg and whey proteins (WPI-EGG) mixture in developing heat-stable O/W emulsions at high concentrations of proteins (10%). Different pHs of 3, 4, 5, 6, and 7 were applied to fabricate heat-stable protein particles. The composite microparticles of WPI-EGG were prepared by heating at 95 °C for 10 min, followed by homogenization under sonication. Moderate pHs of 4–6 were appropriate for aggregate formation and particles whose size varies from 215 to 1333 nm. According to the results, particles generated at pH 5 and 6 showed the viscosity less than 1000 cp due to spherical morphology contrast to the mix of linear and spherical particles fabricated at pH 4 exhibiting viscosity higher than 2000 cp. The particles were characterized with hydrogen bonds and hydrophobic interactions. The lowest surface hydrophobicity was observed for particles prepared at pH 5. Although the greatest denaturation enthalpy and temperature were observed for particles of pH 6, those obtained at pH 5 were capable to form heat-stable emulsions with appropriate viscosity following thermal pasteurization. The increase of disordered random coil structures in the particles (pH 6) was found as main reason of the increased thermal stability at pH 6.

Droplet-based fabrication of alginate hydrogel microparticles in presence of surfactants

Droplet-based fabrication of alginate hydrogel microparticles in presence of surfactants

Fabrication of oxygen-carrying microparticles functionalized with liver ECM-proteins to improve phenotypic three-dimensional in vitro liver assembly, function, and responses.

Oxygen and extracellular matrix (ECM)-derived biopolymers play vital roles in regulating many cellular functions in both the healthy and diseased liver. This study highlights the significance of synergistically tuning the internal microenvironment of three-dimensional (3D) cell aggregates composed of hepatocyte-like cells from the HepG2 human hepatocellular carcinoma cell line and hepatic stellate cells (HSCs) from the LX-2 cell line to enhance oxygen availability and phenotypic ECM ligand presentation for promoting the native metabolic functions of the human liver. First, fluorinated (PFC) chitosan microparticles (MPs) were generated with a microfluidic chip, then their oxygen transport properties were studied using a custom ruthenium-based oxygen sensing approach. Next, to allow for integrin engagements the surfaces of these MPs were functionalized using liver ECM proteins including fibronectin, laminin-111, laminin-511, and laminin-521, then they were used to assemble composite spheriods along with HepG2 cells and HSCs. After in vitro culture, liver-specific functions and cell adhesion patterns were compared between groups and cells showed enhanced liver phenotypic responses to laminin-511 and 521 as evidenced via enhanced E-cadherin and vinculin expression, as well as albumin and urea secretion. Furthermore, hepatocytes and HSCs exhibited more pronounced phenotypic arrangements when cocultured with laminin-511 and 521 modified MPs providing clear evidence that specific ECM proteins have distinctive roles in the phenotypic regulation of liver cells in engineering 3D spheroids. This study advances efforts to create more physiologically relevant organ models allowing for well-defined conditions and phenotypic cell signaling which together improve the relevance of 3D spheroid and organoid models.

Numerical Simulation of the Production of Core-Shell Microparticles

Conventional methods that are commonly used for the preparation of microbubble delivery systems include sonication, high-shear emulsification, and membrane emulsification. However, these methods present significant disadvantages, namely, poor control over the particle size and distribution. To date, engineering core-shell microparticles remains a challenging task. Thus, there is a demand for new techniques that can enable control over the size, composition, stability, and uniformity of microparticles. Microfluidic techniques offer great advantages in the fabrication of microparticles over the conventional processes because they require mild and inert processing conditions. In this work, we present a numerical study based on the finite volume method, for the development of capsules by considering the rheological properties of three phases, air, a perfluorohexane (C6 F14) and a polymeric solution constituted of a solution of 0.25% w/v alginate. This methodology allows studying the stability and behavior of microparticles under different processing conditions.

Red blood cell membrane-camouflaged poly(lactic-co-glycolic acid) microparticles as a potential controlled release drug delivery system for local stellate ganglion microinjection.

The stellate ganglion (SG) is a part of the sympathetic nervous system that has important regulatory effects on several human tissues and organs in the upper body. SG block and intervention have been clinically and preclinically implemented to manage chronic pain in the upper extremities, neck, head, and upper chest as well as chronic heart failure. However, there has been very limited effort to develop and investigate polymer-based drug delivery systems for local delivery to the SG. In this study, we fabricated red blood cell (RBC) membrane-camouflaged poly(lactic-co-glycolic acid) (PLGA) (PLGAM) microparticles for use as a potential long-term controlled release system for local drug delivery. The structure, size, and surface zeta potential results indicated that the spherical PLGAM microparticles were successfully fabricated. Both PLGA and PLGAM microparticles exhibited biocompatibility with human adipose mesenchymal stem cells (ADMSC) and satellite glial cells and showed hemocompatibility. In addition, both PLGA and PLGAM displayed no significant effects on the secretion of proinflammatory cytokines by human monocyte derived macrophages in vitro. We microinjected microparticles into rat SGs and evaluated the retention time of microparticles and the effects of the microparticles on inflammation in vivo over 21 days. Subsequently, we fabricated drug-loaded PLGAM microparticles by using GW2580, a colony stimulating factor-1 receptor inhibitor, as a model drug and assessed its encapsulation efficiency, drug release profiles, biocompatibility, and anti-inflammatory effects in vitro. Our results demonstrated the potential of PLGAM microparticles for long-term controlled local drug release in the SG. STATEMENT OF SIGNIFICANCE: SG block by locally injecting therapeutics to inhibit the activity of the sympathetic nerves provides a valuable benefit to manage chronic pain and chronic heart failure. We describe the fabrication of RBC membrane-camouflaged PLGA microparticles with cytocompatibility, hemocompatibility, and low immunogenicity, and demonstrate that they can be successfully and safely microinjected into rat SGs. The microparticle retention time within SG is over 21 days without eliciting detectable inflammation. Furthermore, we incorporate a CSF-1R inhibitor as a model drug and demonstrate the capacities of long-term drug release and regulation of macrophage functions. The strategies demonstrate the feasibility to locally microinject therapeutics loaded microparticles into SGs and pave the way for further efficacy and disease treatment evaluation.