Preparation Of Microparticles Research Articles

Preparation and Characterization of Polymeric Microparticles Based on Poly(ethylene brassylate-co-squaric Acid) Loaded with Norfloxacin.

In recent years, increasing interest has been accorded to polyester-based polymer microstructures, driven by their promising potential as advanced drug delivery systems. This study presents the preparation and characterization of new polymeric microparticles based on poly(ethylene brassylate-co-squaric acid) loaded with norfloxacin, a broad-spectrum antibiotic. Polymacrolactone was synthesised in mild conditions through the emulsion polymerization of bio-based and renewable monomers, ethylene brassylate, and squaric acid. The microparticles were obtained using the precipitation technique and subsequently subjected to comprehensive characterization. The impact of the copolymer/drug ratio on various properties of the new system was systematically evaluated, confirming the structure of the copolymer and the encapsulation of norfloxacin. The microspheres are approximately spherical and predominantly homogeneously distributed. The average hydrodynamic diameter of the microparticles falls between 400 and 2000 nm, a decrease that is observed with the increase in norfloxacin content. All samples showed good encapsulation efficiency and drug loading capacity, with the highest values obtained for microparticles synthesised using an equal ratio of copolymer and drug. In vitro drug release results disclose that norfloxacin molecules are released in a sustained biphasic manner for up to 24 h. Antimicrobial activity was also studied, with samples showing very good activity against E. coli and moderate activity against S. aureus and E. faecalis. In addition, HDFA human fibroblast cell cultures demonstrated the cytocompatibility of the microparticles.

Reactive Polymer Composite Microparticles Based on Glycidyl Methacrylate and Magnetite Nanoparticles

The modified suspension polymerization technique has been used for the preparation of composite microparticles from the mixture of glycidyl methacrylate (GMA), styrene (S), and divinylbenzene (DVB) in the presence of hydrophobized Fe3O4 nanoparticles. The obtained polymer microspheres were characterized using different instrumental and physicochemical techniques, modified with a zero-order PAMAM dendrimer, and impregnated with palladium(II) acetate solutions to immobilize palladium(II) ions. The resulting materials were preliminarily examined as catalysts in the Suzuki reaction between 4-bromotoluene and phenylboronic acid. It was found that the addition of magnetite particles to the composition of monomers provided polymer microparticles with embedded magnetic nanoparticles. The composite microparticles obtained showed a complex, multi-hollow, or raspberry-like morphology. After their modification, they could serve as recyclable catalysts for reactions that include both 4-bromotoluene and several other aryl bromides.

Stabilization of Black Locust Flower Extract via Encapsulation Using Alginate and Alginate-Chitosan Microparticles.

Black locust flower extract contains various polyphenols and their glucosides contribute to the potential health benefits. After intake of these bioactive compounds and passage through the gastrointestinal tract, their degradation can occur and lead to a loss of biological activity. To overcome this problem, the bioactive compounds should be protected from environmental conditions. This study aimed to encapsulate the black flower extract in the microparticles based on biodegradable polysaccharides, alginate, and chitosan. In the extract, the total antioxidant content was found to be 3.18 ± 0.01 g gallic acid equivalent per 100 g of dry weight. Also, the presence of lipids (16), phenolics (27), organic acids (4), L-aspartic acid derivative, questinol, gibberellic acid, sterol, and saponins (2) was confirmed using the UHPLC-ESI-MS analysis. In vitro assays showed that the extract has weak anti-α-glucosidase activity and moderate antioxidant and cytotoxic activity against the HeLa cell line. The extrusion method with secondary air flow enabled the preparation of microparticles (about 270 μm) encapsulated with extract. An encapsulation efficiency of over 92% was achieved in the alginate and alginate-chitosan microparticles. The swelling study confirmed a lower permeability of alginate-chitosan microparticles compared with alginate microparticles. For both types of microparticles, the release profile of antioxidants in the simulated gastrointestinal fluids at 37 °C followed the Korsmeyer-Peppas model. A lower diffusion coefficient than 0.5 indicated the simple Fick diffusion of antioxidants. The alginate-chitosan microparticles enabled a more sustained release of antioxidants from extract compared to the alginate microparticles. The obtained results indicated an improvement in the antioxidant activity of bioactive compounds from the extract and their protection from degradation in the simulated gastric conditions via encapsulation in the polymer matrixes. Alginate-chitosan showed slightly slower cumulative antioxidant release from microparticles and better antioxidant activity of the extract compared to the alginate system. According to these results, alginate-chitosan microparticles are more suitable for further application in the encapsulation of black locust flower extract. Also, the proposed polymer matrix as a drug delivery system is safe for human use due to its biodegradability and non-toxicity.

Porous Microparticle Preparation via Tuning Electrostatic Breakup Characteristics of a Non-Newtonian Fluid for High-Performance Uranium Extraction

Porous Microparticle Preparation via Tuning Electrostatic Breakup Characteristics of a Non-Newtonian Fluid for High-Performance Uranium Extraction

Preparation of preceramic ferrocene-modified microparticles for the development of uniform porous iron oxide particles and their sustainable recycling

The design of (poly)ferrocene-based microparticle precursors for the preparation of tailored iron oxide microceramics is described. These preceramic materials can be adjusted for various electrochemical applications and separation technologies.

Preparation, physicochemical characterization and swelling properties of composite hydrogel microparticles based on gelatin and pectins with different structure

Composite hydrogel microparticles based on pectins with different structures (callus culture pectin (SVC) and apple pectin (AU)) and gelatin were developed. Hydrogel microparticles were formed by the ionotropic gelation and electrostatic interaction of COO− groups of pectin and NH3+ groups of gelatin, which was confirmed by FTIR spectroscopy. The addition of gelatin to pectin-based gel formulations resulted in a decrease in gel strength, whereas increasing gelatin concentration enhanced this effect. The microparticle gel strength increased in proportion to the increase in the pectin concentration. The DSC and TGA analyzes showed that pectin-gelatin gels had the higher thermal stability than individual pectins. The gel strength, Ca2+ content and thermal stability of the microparticles based on gelatin and SVC pectin with a lower degree of methylesterification (DM) (14.8 %) were higher compared to that of microparticles based on gelatin and AU pectin with a higher DM (40 %). An increase in the SVC concentration, Ca2+ content and gel strength of SVC-gelatin microparticles led to a decrease in the swelling degree in simulated gastrointestinal fluids. The addition of 0.5 % gelatin to gels based on AU pectin resulted in increased stability of the microparticles in gastrointestinal fluids, while the microparticles from AU without gelatin were destroyed.

The potential of starch-chitosan blends with poloxamer for the preparation of microparticles by spray-drying

Using biopolymers as wall materials in spray drying poses challenges, particularly in attaining flowability and thermal stability among their physicochemical properties. This paper addresses these challenges by preparing microparticles using a blend of starch–chitosan and a poloxamer, commercially named Pluronic® F127. We aimed to elucidate the effects of varying poloxamer concentrations on the resulting particles through the spray drying technique. Blends with a poloxamer concentration of 3% (w/v) demonstrated a notably higher yield, especially when compared to those with 0% and 1% concentrations. Microparticles with 3% and 5% (w/v) poloxamer displayed a narrower particle size distribution, with the 3% blend showing a superior yield attributed to arrangements of blend components that improve flowability. X-ray diffraction analysis showcased the characteristic peaks of A-type starch form, with shifts suggesting enhanced interactions between components. Microparticles with increased poloxamer content showed elevated thermal degradation temperatures, with the 3% blend registering a significant rise, opening avenues for encapsulating heat-sensitive bioactive. This study primarily focuses on the preparation and basic characterization of microparticles. It underscores the potential of blends with optimal poloxamer concentrations in microencapsulation, emphasizing further research to harness their capabilities thoroughly.

Ultrasound-assisted preparation of uniform BiInSn phase change microparticles for enhanced thermal interface materials through in-situ low-temperature soldering

Micro/nano scale metallic phase change materials (mPCM) have attracted interested for constructing thermal interface materials (TIM), which can rapidly transfer heat away and store the latent heat and buffer the temperature on the course of the high-power operation. However, it is still a great challenge to prepare mPCM particles in micro/nano scale with uniform size and morphology. Here, we successfully prepared a series of BiInSn spherical particles with adjustable size in the range of 1.21–5.45 μm through an ultrasonic-assisted bath method. Especially, the BiInSn spherical particles with the uniform size of ∼5 μm are prepared under the condition of 450 W, 70 °C and 40 min. The prepared BiInSn particles maintain the characteristics of low melting point (∼61 °C) and high latent heat (∼29.95 J g−1) of bulk BiInSn, which are further compounded with Al particles to construct a TIM, and a high thermal conductivity (3.24 W m−1K−1) is reached by adding BiInSn spheres (5 μm, 5 wt%) as functional fillers. The SEM reveals BiInSn microparticles can melt and bridge the adjacent Al particles to build an efficient heat-conducting network. The mPCM particles will be increasingly used in other fields including 3D printing, sensing, smart materials and so on.

Application of low-, and medium-molecular weight chitosan for preparation of spray-dried microparticles loaded with Ferulago angulata essential oil: Physicochemical, antioxidant, antibacterial and in-vitro release properties

The present work aimed at spray-drying encapsulation of Chavir (Ferulago angulata) essential oil (EO) using low-, and medium-molecular weight chitosan. The obtained EO was observed to be mainly composed of β-ocimene, α-pinene, and bornyl acetate with antioxidant, and antimicrobial activity. The results indicated that stable emulsions with uniform particle size distribution and encapsulation efficiencies higher than 93 % could be prepared using chitosan as feed for spray-drying. In addition, spray-drying resulted in fabricating stable microspheres with yields higher than 50 %, uniform particle size, and encapsulation efficiency exceeding 70 %. The microspheres were fairly soluble and hygroscopic, and exhibited antioxidant and bacteriostatic activities with a biphasic release pattern. FTIR characterisation confirmed successful encapsulation of EO and thermal properties of microspheres indicated enhanced stability of EO after microencapsulation. Overall, it was revealed that molecular weight of chitosan and EO:chitosan ratio affects some physicochemical properties of obtained chitosan microspheres.

Preparation of magnetic Janus microparticles for the rapid removal of microplastics from water

The continuous spread of microplastics in aquatic environments poses a growing concern and a potential risk to human health. To address this concern, this paper presents a novel approach using magnetic Janus microparticles (MJMs) synthesized via a modified Pickering emulsion method with aminated Fe3O4@SiO2 as the raw material. The effectiveness of these MJMs in removing polystyrene (PS) and polyethylene (PE) microplastics from water was investigated. Paraffin was employed as the masking agent, while N-Octadecylphosphosphonic acid (PAC18) was used as the graft material for MJM preparation. The resulting particles exhibited a distinctive asymmetric flower-shaped structure on the surface, which was confirmed through various analytical techniques including FTIR, TGA, SEM, and water phase contact angle analysis. The MJMs demonstrated exceptional efficiency in adsorbing microplastics. With a microplastic suspension concentration of 2 mg/mL and an adsorbent dosage of 1 mg/mL, the MJMs can attain removal efficiencies of 92.08 % for PS and 60.67 % for PE in just 20 min of contact time. The effectiveness of the adsorption process was attributed to several factors, including hydrophobic interactions, cation-π interactions, electrostatic attraction, and the efficient dispersion of particles in water, as revealed by size distribution and zeta potential analysis. Additionally, kinetic and thermodynamic studies confirmed the remarkable adsorption rate and capacity of the MJMs (0.759 min−1 and 2.72 mg/mg for PS, 0.539 min−1 and 2.42 mg/mg for PE), highlighting their potential as a promising method for rapidly removing microplastics from water. This work provides valuable insights into the development of effective strategies for addressing microplastic pollution in aquatic environments.

A general dispersion solution to prepare spherical microparticles of indium-based liquid metals by shear force

The optimized dispersion solution for preparing well-dispersed In-based liquid metal (LM) microparticles via shear force was a glycerol solution containing 20 vol% polyethylene glycol and 0.2 wt% citric acid. The study demonstrated that the mean curvature obtained from volume of fluid (VOF) simulations can be considered as a significant reference index for optimizing solutions and technical parameters for the fabrication of In-based LM powders. Additionally, the results showed that molten In-based LM microparticles fuse as a whole as the oxide film is removed and the neighboring microparticles coalesce. Furthermore, the average diameter of In-Bi-Sn microparticles was the biggest, followed by that of In-Bi, In, and In-Sn microparticles, which was just opposite with the trend of mean curvature of the microparticles obtained from simulation. These findings provide new insights into the preparation and properties of LM microparticles, which are of great interest to the electronics industry.

Recent Progress of Droplet Microfluidic Emulsification Based Synthesis of Functional Microparticles.

The remarkable control function over the functional material formation process enabled by droplet microfluidic emulsification approaches can lead to the efficient and one-step encapsulation of active substances in microparticles, with the microparticle characteristics well regulated. In comparison to the conventional fabrication methods, droplet microfluidic technology can not only construct microparticles with various shapes, but also provide excellent templates, which enrich and expand the application fields of microparticles. For instance, intersection with disciplines in pharmacy, life sciences, and others, modifying the structure of microspheres and appending functional materials can be completed in the preparation of microparticles. The as-prepared polymer particles have great potential in a wide range of applications for chemical analysis, heavy metal adsorption, and detection. This review systematically introduces the devices and basic principles of particle preparation using droplet microfluidic technology and discusses the research of functional microparticle formation with high monodispersity, involving a plethora of types including spherical, nonspherical, and Janus type, as well as core-shell, hole-shell, and controllable multicompartment particles. Moreover, this review paper also exhibits a critical analysis of the current status and existing challenges, and outlook of the future development in the emerging fields has been discussed.

Preliminary assessment of influence of calcium alginate beads on the dissolution of meloxicam

The purpose of the study was to evaluate the preparation of alginate-based microparticles with meloxicam (MLX). A poorly soluble substance classified to BCS class II, it was chosen as a model substance. The ionotropic gelation was the process used for the formation of microparticles. The impact of the carrier on the dissolution of MLX from this formulation was also investigated. Study was realized in few steps: preparation of polymer particles containing suspended MLX in their structure; drying them in various conditions (room temperature, freeze drying); morphology characterization and then assessment of impact of polymer on dissolution of the model substance. Also, DDSolver software was used for checking the similarity of release profiles. Validated UV-Vis spectrophotometric method was used for MLX determination on different steps of work. As it showed, calcium alginate particles were successfully prepared with ionotropic gelation. The drying method of prepared particles has a substantial impact on the release profiles of meloxicam, and these formulations significantly improve the MLX release from this form of the delivery system.

Preparation and Evaluation of Inhalable Amifostine Microparticles Using Wet Ball Milling.

The conventional dosage form of Ethyol® (amifostine), a sterile lyophilized powder, involves reconstituting it with 9.7 mL of sterile 0.9% sodium chloride in accordance with the United States Pharmacopeia specifications for intravenous infusion. The purpose of this study was to develop inhalable microparticles of amifostine (AMF) and compare the physicochemical properties and inhalation efficiency of AMF microparticles prepared by different methods (jet milling and wet ball milling) and different solvents (methanol, ethanol, chloroform, and toluene). Inhalable microparticles of AMF dry powder were prepared using a wet ball-milling process with polar and non-polar solvents to improve their efficacy when delivered through the pulmonary route. The wet ball-milling process was performed as follows: AMF (10 g), zirconia balls (50 g), and solvent (20 mL) were mixed and placed in a cylindrical stainless-steel jar. Wet ball milling was performed at 400 rpm for 15 min. The physicochemical properties and aerodynamic characteristics of the prepared samples were evaluated. The physicochemical properties of wet-ball-milled microparticles (WBM-M and WBM-E) using polar solvents were confirmed. Aerodynamic characterization was not used to measure the % fine particle fraction (% FPF) value in the raw AMF. The % FPF value of JM was 26.9 ± 5.8%. The % FPF values of the wet-ball-milled microparticles WBM-M and WBM-E prepared using polar solvents were 34.5 ± 0.2% and 27.9 ± 0.7%, respectively; while the % FPF values of the wet-ball-milled microparticles WBM-C and WBM-T prepared using non-polar solvents were 45.5 ± 0.6% and 44.7 ± 0.3%, respectively. Using a non-polar solvent in the wet ball-milling process resulted in a more homogeneous and stable crystal form of the fine AMF powder than using a polar solvent.

Rationalized design to explore the full potential of PLGA microspheres as drug delivery systems

Polymeric microparticles are widely used as drug delivery platforms either alone or embedded in more complex structures for regenerative medicine. Emulsion-solvent evaporation is the most extensively used technique for microparticles preparation. Despite the apparent simplicity of this method, there is no general procedure for producing microparticles of predictable characteristics (particle size, size distribution, encapsulation efficiency, and drug loading). Hybrid systems such as neurofuzzy logic allow identifying relationships between inputs and outputs, expressing the generated mathematical models through rules in linguistic format. In this work, the relationships between the variables involved in the emulsion-solvent evaporation process and the quality parameters of PLGA microparticles as drug delivery systems were established. Neurofuzzy logic software was able to generate models of high predictability (> 85%) for the microspheres properties namely particle size, size distribution, encapsulation efficiency and drug loading. Moreover, the generated sets of IF-THEN rules allowed to dictate general guidelines to better select the PLGA microparticles formulation parameters. This approach would be of great interest as a starting point to set-up protocols for the development of PLGA microparticles obtained by emulsion-solvent evaporation for many applications.

Preparation, characterization and biocompatibility of calcium peroxide-loaded polycaprolactone microparticles.

To explore the physicochemical characteristics and biocompatibility of calcium peroxide (CPO)-loaded polycaprolactone (PCL) microparticle. The CPO/PCL particles were prepared. The morphology and elemental distribution of CPO, PCL and CPO/PCL particles were observed with scanning electron microscopy and energy dispersive spectroscopy, respectively. Rat adipose mesenchymal stem cells were isolated and treated with different concentrations (0.10%, 0.25%, 0.50%, 1.00%) of CPO or CPO/PCL particles. The mesenchymal stem cells were cultured in normal media or osteogenic differentiation media under the hypoxia/normoxia conditions, and the amount of released O2 and H2O2 after CPO/PCL treatment were detected. The gene expressions of alkaline phosphatase (ALP), Runt-associated transcription factor 2 (RUNX2), osteopontin (OPN) and osteocalcin (OCN) were detected by realtime RT-PCR. SD rats were subcutaneously injected with 1.00% CPO/PCL particles and the pathological changes and infiltration of immune cells were observed with HE staining and immunohistochemistry at day 7 and day 14 after injection. Scanning electron microscope showed that CPO particles had a polygonal structure, PCL particles were in a small spherical plastic particle state, and CPO/PCL particles had a block-like crystal structure. Energy dispersive spectroscopy revealed that PCL particles showed no calcium mapping, while CPO/PCL particles showed obvious and uniform calcium mapping. The concentrations of O2 and H2O2 released by CPO/PCL particles were lower than those of CPO group, and the oxygen release time was longer. The expressions of Alp, Runx2, Ocn and Opn increased with the higher content of CPO/PCL particles under hypoxia in osteogenic differentiation culture and normal culture, and the induction was more obvious under osteogenic differentiation conditions (all P<0.05). HE staining results showed that the muscle tissue fibers around the injection site were scattered and disorderly distributed, with varying sizes and thicknesses at day 7 after particle injection. Significant vascular congestion, widened gaps, mild interstitial congestion, local edema, inflammatory cell infiltration, and large area vacuolization were observed in some tissues of rats. At day 14 after microparticle injection, the muscle tissue around the injection site and the tissue fibers at the microparticle implantation site were arranged neatly, and the gap size was not thickened, the vascular congestion, local inflammatory cell infiltration, and vacuolization were significantly improved compared with those at day 7. The immunohistochemical staining results showed that the expressions of CD3 and CD68 positive cells significantly increased in the surrounding muscle tissue, and were densely distributed in a large area at day 7 after particle injection. At day 14 of microparticle injection, the numbers of CD3 and CD68 positive cells in peripheral muscle tissue and tissue at the site of particle implantation were lower than those at day 7 (all P<0.01). CPO/PCL particles have good oxygen release activity, low damage to tissue, and excellent biocompatibility.

Effects of different drying methods on the properties, stability, and controlled release of Cornus officinalis flavonoids microparticles.

To improve the stability and solubility of Cornus officinalis flavonoid (COF), spray drying (SD), freeze-drying (FD), and microwave freeze drying (MFD) were used to encapsulate COF using whey isolate protein (WPI) and gum arabic as wall materials. The characterization of COF microparticles was performed with encapsulation efficiency (EE), particle size, morphology, antioxidant activity, structure, thermal stability, color, stability during storage, and in vitro solubility. The results showed that COF was successfully encapsulated in the wall material with an EE between 78.86% and 91.11%. The freeze-dried microparticles had the highest EE (91.11%) and the lowest particle size (12.42±16.73µm). However, the particle size of COF microparticles of SD and MFD was relatively large. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging capacity of the microparticles obtained from SD (89.36mgVc /g) was higher than that of MFD (85.67mgVc /g), but the drying time and energy consumption of microparticles dried by SD and MFD were lower than those of FD. Furthermore, the spray-dried COF microparticles had higher stability compared to FD and MFD when stored at 4°C for 30 days. In addition, the dissolution of COF microparticles prepared by SD and MFD was 55.64% and 57.35%, respectively, in simulated intestinal fluids, which was lower than that of FD (64.47%). Therefore, the application of microencapsulation technology showed significant advantages in improving the stability and solubility of COF, and the SD can be used for the preparation of microparticles considering energy cost and quality. PRACTICAL APPLICATION: COF is an important bioactive ingredient, but its poor stability and water solubility decreases its pharmacological value. COF microparticles can improve the stability of COF, enhance the slow-release effect, and expand its application in the food field. The drying method will affect the properties of COF microparticles. Thus, the structures and properties analysis of COF microparticles by different drying methods can provide a reference basis for the preparation and application of COF microparticles.

Polysaccharide-Based Carriers for Pulmonary Insulin Delivery: The Potential of Coffee as an Unconventional Source.

Non-invasive routes for insulin delivery are emerging as alternatives to currently painful subcutaneous injections. For pulmonary delivery, formulations may be in powdered particle form, using carriers such as polysaccharides to stabilise the active principle. Roasted coffee beans and spent coffee grounds (SCG) are rich in polysaccharides, namely galactomannans and arabinogalactans. In this work, the polysaccharides were obtained from roasted coffee and SCG for the preparation of insulin-loaded microparticles. The galactomannan and arabinogalactan-rich fractions of coffee beverages were purified by ultrafiltration and separated by graded ethanol precipitations at 50% and 75%, respectively. For SCG, galactomannan-rich and arabinogalactan-rich fractions were recovered by microwave-assisted extraction at 150 °C and at 180 °C, followed by ultrafiltration. Each extract was spray-dried with insulin 10% (w/w). All microparticles had a raisin-like morphology and average diameters of 1-5 µm, which are appropriate for pulmonary delivery. Galactomannan-based microparticles, independently of their source, released insulin in a gradual manner, while arabinogalactan-based ones presented a burst release. The microparticles were seen to be non-cytotoxic for cells representative of the lung, specifically lung epithelial cells (A549) and macrophages (Raw 264.7) up to 1 mg/mL. This work shows how coffee can be a sustainable source of polysaccharide carriers for insulin delivery via the pulmonary route.

Preparation of microparticles and nanoparticles using membrane-assisted dispersion, micromixing, and evaporation processes

Synthetic microporous membranes are increasingly used for energy-efficient and controlled production of micro- and nanoparticles and micro- and nanoemulsions with tuneable morphology and physicochemical properties through various micromixing, emulsification, and evaporation processes. In emulsification processes, the membrane pores are used for dispersed phase injection and size-controlled generation of droplets and droplet-templated particles. In micromixing processes, membrane is utilised as a micromixer for mixing two miscible liquids, usually solvent and antisolvent-rich solutions, which leads to the creation of supersaturation and subsequent nanoprecipitation or crystallisation. In membrane evaporation processes, membrane is used to prevent phase dispersion while allowing efficient molecular diffusion of solvent and/or antisolvent vapour through gas-filled pores. Membrane dispersion processes can be operated continuously by decoupling shear stress on the membrane surface from cross flow using tube insets, flow pulsations, swirling flow, membrane oscillations or membrane rotations. Droplet generation and solidification can be performed continuously in a single pass by connecting membrane module with a downstream reactor. Membrane dispersion processes can be used for production of nanoparticles such as nanovesicles (liposomes, micelles, ethosomes, and niosomes), nanogels, polymeric, lipid and metallic nanoparticles, and nanocrystals. The main advantages of membrane-assisted particle generation are in low energy consumption, controlled geometry and hydrodynamic conditions at the microscale level, flexible throughput due to modular and scalable design of membrane devices, and a wide choice of available microporous membranes with various wall porosities, wettabilities, pore sizes, and pore morphologies to suit different applications.

LCST-mediated phase separation strategy for preparation of poly(amino alcohol ethers) microparticle-gelatin hydrogel composites

In this study, we report a facile two-step strategy to aid the preparation of microparticle-hydrogel composites. By leveraging amine-epoxy “click” chemistry, in combination with lower critical solution temperature (LCST)-mediated phase separation phenomenon of the in situ formed poly(amino alcohol ethers) (TP) prepolymer in water, as well as integration of gelatin, a series of poly(amino alcohol ethers) microparticle-gelatin hydrogel (TGP) composites can be readily prepared through the simultaneous preparation of bulk hydrogel network and microparticles. Our strategy allows easy tuning of microstructures and mechanics, as well as degradation properties of the obtained TGP composites through varying the volume ratio of TP prepolymer solution and gelatin solution. Moreover, applicability of such TGP composites to modulate cell response was demonstrated in vitro with NIH3T3 fibroblasts and chicken primary neurons. Furthermore, with hydrophobic domains in microparticles, such TGP composites are also feasible to tailor anti-inflammatory effect via curcumin encapsulation. Altogether, this study provides new insights into the design strategy to achieve microparticle-hydrogel composites to warrant consideration for drug delivery and tissue engineering applications.