Porous Copolymers of 3-(Trimethoxysilyl)propyl Methacrylate with Trimethylpropane Trimethacrylate Preparation: Structural Characterization and Thermal Degradation.

Porous polymeric microspheres are among the most effective adsorbents. They can be synthesized from numerous monomers using different kinds of polymerization techniques with a broad selection of synthesis factors. The main goal of this study was to prepare copolymeric microspheres and establish the relationship between copolymerization parameters and the porosity and thermal stability of the newly synthesized materials. Porous microspheres were obtained via heterogenous radical copolymerization using 3-(trimethoxysilyl)propyl methacrylate (TMPSM) as functional monomers and trimethylolpropane trimethacrylate (TRIM) as the crosslinker. In the course of the copolymerization, toluene or chlorobenzene was used as the pore-forming diluent. Consequently, highly porous microspheres were produced. Their specific surface area was established by a nitrogen adsorption/desorption method and it was in the range of 382 m2/g to 457 m2/g for toluene and 357-500 m2/g in the case of chlorobenzene. The thermal degradation process was monitored by thermogravimetry and differential scanning calorimetry methods in inert and oxidative conditions. The copolymers were stable up to 269-283 °C in a helium atmosphere, whereas in synthetic air the range was 266-298 °C, as determined by the temperature of 5% mass loss. Thermal stability of the investigated copolymers increased along with an increasing TMPSM amount in the copolymerization mixture. In addition, the poly(TMSPM-co-TRIM) copolymers were effectively used as the stationary phase in GC analyses.

Development of Resorbable Phosphate-Based Glass Microspheres as MRI Contrast Media Agents.

In this research, resorbable phosphate-based glass (PBG) compositions were developed using varying modifier oxides including iron (Fe2O3), copper (CuO), and manganese (MnO2), and then processed via a rapid single-stage flame spheroidisation process to manufacture dense (i.e., solid) and highly porous microspheres. Solid (63-200 µm) and porous (100-200 µm) microspheres were produced and characterised via SEM, XRD, and EDX to investigate their surface topography, structural properties, and elemental distribution. Complementary NMR investigations revealed the formation of Q2, Q1, and Q0 phosphate species within the porous and solid microspheres, and degradation studies performed to evaluate mass loss, particle size, and pH changes over 28 days showed no significant differences among the microspheres (63-71 µm) investigated. The microspheres produced were then investigated using clinical (1.5 T) and preclinical (7 T) MRI systems to determine the R1 and R2 relaxation rates. Among the compositions investigated, manganese-based porous and solid microspheres revealed enhanced levels of R2 (9.7-10.5 s-1 for 1.5 T; 17.1-18.9 s-1 for 7 T) and R1 (3.4-3.9 s-1 for 1.5 T; 2.2-2.3 s-1 for 7 T) when compared to the copper and iron-based microsphere samples. This was suggested to be due to paramagnetic ions present in the Mn-based microspheres. It is also suggested that the porosity in the resorbable PBG porous microspheres could be further explored for loading with drugs or other biologics. This would further advance these materials as MRI theranostic agents and generate new opportunities for MRI contrast-enhancement oral-delivery applications.

Dexamethasone Long-Term Controlled Release from Injectable Dual-Network Hydrogels with Porous Microspheres Immunomodulation Promotes Bone Regeneration.

Long-lasting, controlled-release, and minimally invasive injectable platforms that provide a stable blood concentration to promote bone regeneration are less well developed. Using hexagonal mesoporous silica (HMS) loaded with dexamethasone (DEX) and poly(lactic-co-glycolic acid) (PLGA), we prepared porous DEX/HMS/PLGA microspheres (PDHP). In contrast to HMS/PLGA microspheres (HP), porous HMS/PLGA microspheres (PHP), DEX/PLGA microspheres (DP), and DEX/HMS/PLGA microspheres (DHP), PDHP showed notable immuno-coordinated osteogenic capabilities and were best at promoting bone mesenchymal stem cell proliferation and osteogenic differentiation. PDHP were combined with methacrylated silk (SilMA) and sodium alginate (SA) to form an injectable photocurable dual-network hydrogel platform that could continuously release the drug for more than 4 months. By adjusting the content of the microspheres in the hydrogel, a zero-order release hydrogel platform was obtained in vitro for 48 days. When the microsphere content was 1%, the hydrogel platform exhibited the best biocompatibility and osteogenic effects. The expression levels of the osteogenic gene alkaline phosphatases, BMP-2 and OPN were 10 to 15 times higher in the 1% group than in the 0% group, respectively. In addition, the 1% microsphere hydrogel strongly stimulated macrophage polarization to the M2 phenotype, establishing an immunological milieu that supports bone regrowth. The aforementioned outcomes were also observed in vivo. The most successful method for correcting cranial bone abnormalities in SD rats was to use a hydrogel called SilMA/SA containing 1% drug-loaded porous microspheres (PDHP/SS). The angiogenic and osteogenic effects of this treatment were also noticeably greater in the PDHP/SS group than in the control and blank groups. In addition, PDHP/SS polarized M2 macrophages and suppressed M1 macrophages in vivo, which reduced the local immune-inflammatory response, promoted angiogenesis, and cooperatively aided in situ bone healing. This work highlights the potential application of an advanced hydrogel platform for long-term, on-demand, controlled release for bone tissue engineering.

In vitro and in vivo degradation profile, biocompatibility of poly-L-lactic acid porous microspheres.

The objective of this study is to evaluate the in vitro and in vivo degradation profile and biocompatibility of poly-L-lactic acid (PLLA) porous microspheres (PMs) for their potential application as injectable microcarrier or micro-scaffolds materials in the research and clinical use of craniofacial cartilage repair. In this study, PLLA PMs prepared exhibited spherical shape and uniform surface pores followed by 24-week evaluations for degradation behavior and biocompatibility. In vitro degradation analysis encompassed morphological examination, pH monitoring, molecular weight analysis, thermodynamic assessment, and chemical structure analysis. After 12 weeks of in vitro degradation, PMs maintained a regular porous spherical structure. Molecular weight and glass transition temperature of PLLA PMs decreased over time, accompanying with an initial increase and subsequent decrease in crystallinity. Enzymatic degradation caused morphological changes and accelerated degradation in the in vitro studies. Finally, in vivo evaluations involved subcutaneous implantation of PLLA PMs in rats, demonstrating biocompatibility by enhancing type I and type III collagen regeneration as observed in histological analysis. The results demonstrated that PLLA PMs were able to maintain their spherical structure for 12 weeks, promoting the generation of collagen at the implantation site, meeting the time requirements for craniofacial cartilage repair.

A composite of AgNPs and lignin porous microspheres via in-situ reduction of Ag+ and its catalytic performance.

Despite the widespread utilization of nano silver composites in the domain of catalytic hydrogenation of aromatic pollutants in wastewater, certain challenges persist, including the excessive consumption of chemical reagents during the preparation process and the difficulty in recycling. In this study, silver ions were reduced in-situ by taking advantage of the adsorptive and reducing capacities of hydroxyls and amino groups on lignin porous microspheres (LPMs) under mild ultrasonic conditions, and lignin porous microspheres loaded with silver nanoparticles (Ag@LPMs) were conveniently prepared. Ag@LPMs had excellent catalytic and cycling performances for p-nitrophenol (4-NP), methylene blue (MB) and methyl orange (MO). The 4-NP could be completely reduced to 4-AP within 155 s under the catalysis of Ag@LPMs, with a pseudo-first-order kinetic constant of 1.28 min-1. Furthermore, Ag@LPMs could still complete the catalytic reduction of 4-NP within 10 min after five cycles. Ag@LPMs with the particle size ranging from 100 to 200 µm conferred ease of recycling, and the porous structure effectively resolved the issue of sluggish mass transfer encountered during the catalytic process. At the same time, the binding force of nano silver and LPMs obtained by ultrasonic was stronger than that of heating, so the materials prepared by ultrasonic had better cycling performance. Silver ions concentration and pH value in the preparation process affected the catalytic performance of Ag@LPMs, 50 mmol/L Ag+ and pH value of 7 turned out to be the optimization conditions.

Doped Porous Carbon Spheres with Controllable Vesicle Structure: Preparation and the Effects of Pore Size on Electromagnetic Wave Absorption Properties.

This work reports on the preparation of uniform vesicle-structural carbon spheres doped with heteroatoms of N, P, and S, with the pore sizes strictly controlled by the hard templates of monodisperse submicron SiO2 spheres. The uniformly doped vesicular carbon microspheres are obtained in three steps: Stöber hydrolysis for the SiO2; in situ polymerization for the immobilization; and alkaline etching after carbonization. The size of the vesicles can be easily adjusted by regulating the particle size of the submicron SiO2 spheres, which has a significant effect on its electromagnetic wave (EMW) absorption performance. Compared with microspheres with pore sizes of 180 and 480 nm, when the vesicle aperture is 327 nm, with only 5.5 wt.% filling load and 1.9 mm thickness, the material shows the best EMW absorption behavior with the effective absorption bandwidth (EAB) covers the entire Ku band (6.32 GHz) and the minimum reflection loss (RLmin) of -36.10 dB, suggesting the optimized pore size of the microspheres can significantly improve the overall impedance matching of the material and achieve broadband wave absorption. This work paves the way for the enhancement of EMW absorption properties of porous material by optimizing the pore size of uniform apertures while maintaining their composition.

Adipose-derived mesenchymal stem cell-incorporated PLLA porous microspheres for cartilage regeneration.

BACKGROUND: In facial plastic surgery, patients with nasal deformity are often treated by rib cartilage transplantation. In recent years, cartilage tissue engineering has developed as an alternative to complex surgery for patients with minor nasal defects via injection of nasal filler material. In this study, we prepared an injectable nasal filler material containing poly-L-lactic acid (PLLA) porous microspheres (PMs), hyaluronic acid (HA) and adipose-derived mesenchymal stem cells (ADMSCs). METHODS: We seeded ADMSCs into as-prepared PLLA PMs using our newly invented centrifugation perfusion technique. Then, HA was mixed with ADMSC-incorporated PLLA PMs to form a hydrophilic and injectable cell delivery system (ADMSC-incorporated PMH). RESULTS: We evaluated the biocompatibility of PMH in vitro and in vivo. PMH has good injectability and provides a favorable environment for the proliferation and chondrogenic differentiation of ADMSCs. In vivo experiments, we observed that PMH has good biocompatibility and cartilage regeneration ability. CONCLUSION: In this study, a injectable cell delivery system was successfully constructed. We believe that PMH has potential application in cartilage tissue engineering, especially in nasal cartilage regeneration.

Preparation and mechanism study of hydrogen bond induced enhanced composited gelatin microsphere probe.

Fluorescent probes offer rapid and efficient detection of metal ions. However, their properties, including high biotoxicity and low detection limits, often limit their utility in biological systems. In this study, we used a microfluidic approach to fabricate photocrosslinked gelatin microspheres with a micropore, providing a straightforward method for loading fluorescent probes into these microspheres based on the adsorption effect and hydrogen bonding interaction. The gelatin microsphere loaded probes, GelMA/TPA-DAP and GelMA/TPA-ISO-HNO were designed and obtained. The results show that these probes exhibit obviously low biotoxicity compared to the original molecular probes TPA-DAP and TPA-ISO-HNO. Simultaneously, it is found that GelMA/TPA-DAP and GelMA/TPA-ISO-HNO have better detection sensitivity, the detection limits are 35.4 nM for Cu2+, 16.5 nM for Co2+ and 20.5 nM for Ni2+ for GelMA/TPA-DAP probe. Compared to the original TPA-DAP they are improved by 37.2 %, 26.3 % and 22.6 % respectively. The corresponding coordination constants were 10.8 × 105, 4.11×105 and 6.04×105, which is larger than homologous TPA-DAP. Similar results were also verified in the GelMA/TPA-ISO-HNO probe. The mechanism was investigated in detail by theoretical simulations and advanced spectral analysis. The density functional theory (DFT) simulations show that the probes are anchored inside the microspheres and the molecular structure is modified due to the hydrogen bonding interaction between the microsphere and the molecular probe, which makes GelMA/TPA-DAP exhibit stronger coordination capacity with metal ions than homologous TPA-DAP. In addition, the adsorption effect also provided some synergistic enhancement contribution. Meanwhile, cellular experiments have also shown that the composite microspheres can improve the biocompatibility of the probe and will provide a wider range of applications towards bioassay. This simple and effective method will provide a convenient way to improve the performance of fluorescent probes and their biological applications.

Mi-BMSCs alleviate inflammation and fibrosis in CCl4-and TAA-induced liver cirrhosis by inhibiting TGF-ß/Smad signaling.

Cirrhosis is an aggressive disease, and over 80 % of liver cancer patients are complicated by cirrhosis, which lacks effective therapies. Transplantation of mesenchymal stem cells (MSCs) is a promising option for treating liver cirrhosis. However, this therapeutic approach is often challenged by the low homing ability and short survival time of transplanted MSCs in vivo. Therefore, a novel and efficient cell delivery system for MSCs is urgently required. This new system can effectively extend the persistence and duration of MSCs in vivo. In this study, we present novel porous microspheres with microfluidic electrospray technology for the encapsulation of bone marrow-derived MSCs (BMSCs) in the treatment of liver cirrhosis. Porous microspheres loaded with BMSCs (Mi-BMSCs) exhibit good biocompatibility and demonstrate better anti-inflammatory properties than BMSCs alone. Mi-BMSCs significantly increase the duration of BMSCs and exert potent anti-inflammatory and anti-fibrosis effects against CCl4 and TAA-induced liver cirrhosis by targeting the TGF-ß/Smad signaling pathway to ameliorate cirrhosis, which highlight the potential of Mi-BMSCs as a promising therapeutic approach for early liver cirrhosis.

Mechanistic Study of the Formation of Multicomponent Oxide Porous Microspheres (MICROSCAFS®) by Cryo-Scanning Electron Microscopy.

Multicomponent oxide microspheres with interconnected macroporosity (MICROSCAFS®) are new materials with great potential as support materials for photocatalysis, optimized for real life applications and for other uses that are still being explored. They are obtained from an adapted sol-gel process combined with phase separation phenomena that occur within the water droplets of an emulsion. We present here a methodology based on cryogenic scanning electron microscopy (cryo-SEM) that allows, with minimal specimen preparation, the direct and in situ visualization of 'wet' alkoxide-derived microstructures, for the mechanistic study of the complex process of MICROSCAFS® generation. It is simultaneously combined with energy dispersive X-ray spectroscopy (EDS) to visualize phase separation phenomena and study the chemical elemental composition at specific regions of the sample and reaction times.

Preparation of MoS2/MXene/NC Porous Composite Microspheres with Wrinkled Surface and Their Microwave Absorption Performances.

In this paper, a MoS2/MXene/N-doped carbon (NC) porous composite microsphere with a wrinkled surface was designed and constructed. Lithium fluoride exfoliation and lithium-ion etching fabricated two types of 2D assembly elements, MXene (Ti3C2Tx) and MoS2 nanosheets. The two nanosheets were self-assembled by an ultrasonic spray technique with high-temperature reduction, and MoS2/MXene microspheres with 3Dwrinkled shapes were obtained. The coating of the surface NC layer was achieved by the carbonization of a polydopamine (PDA) precursor formed by the self-polymerization of dopamine. The amount of PDA coating and raw material ratio significantly affect the microstructure and electromagnetic wave absorption performance. The optimal MXene to MoS2 mass ratio is 5:1, and the optimal coating time and filler amount are 8 h and 40%. MoS2/MXene/NC composite microspheres exhibit excellent absorption performance with low reflection losses (RLmin) of -52.9 dB at 6.4 GHz and high adequate absorption bandwidths of 5.2 GHz. By adjusting the thickness of the absorber, the full coverage of the C-Ku band (4-18 GHz) can be achieved. As a new composite absorber, it has significant potential applications.

CGRP-Loaded Porous Microspheres Protect BMSCs for Alveolar Bone Regeneration in the Periodontitis Microenvironment.

Periodontitis is a prevalent dental disease marked by progressive destruction of tooth-supporting tissues, and the recovery of bone defects after periodontitis remains challenging. Although stem cell-based therapy is a promising treatment for periodontal tissue regeneration, the function of mesenchymal stem cells is constantly impaired by the inflammatory microenvironment, leading to compromised treatment outcomes. Herein, calcitonin gene-related peptide (CGRP)-loaded porous microspheres (PMs) are prepared to protect bone marrow mesenchymal stem cells (BMSCs) against inflammatory mediators in periodontitis. The released CGRP can effectively ameliorate the inflammation-induced dysfunction of BMSCs, which may involve suppressing the ROS (reactive oxygen species)/NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3)/Caspase-1 (CASP1) pathway. Moreover, the porous architecture of PMs provides effective cell-carrying capacity and physical protection for BMSCs during transplantation. In vivo experiments demonstrate that CGRP/BMSC-loaded PMs can effectively inhibit inflammation and improve osteogenic activity, resulting in better periodontal bone regeneration. This study focuses on the protection of stem cell function in the inflammatory microenvironment, which is important for stem cell-mediated tissue regeneration and repair under inflammatory conditions.

Encapsulating lithium at the microscale: selective deposition in carbon-doped graphitic carbon nitride spheres.

For stable lithium deposition without dendrites, three-dimensional (3D) porous structure has been intensively investigated. Here, we report the use of carbon-doped graphitic carbon nitride (C-doped g-C3N4) microspheres as a 3D host for lithium to suppress dendrite formation, which is crucial for stable lithium deposition. The C-doped g-C3N4microspheres have a high surface area and porosity, allowing for efficient lithium accommodation with high accessibility. The carbon-doping of the g-C3N4microspheres confers lithiophilic properties, which facilitate the regulation of Li+flux and dense filling of cavities with nucleated lithium, thereby preventing volume expansion and promoting dendrite-free Li deposition. The electrochemical performance was improved with cyclic stability and high Coulombic efficiency over 260 cycles at 1.0 mA cm-2for 1.0 mAh cm-2, and even over 70 cycles at 5.0 mA cm-2for 3.0 mAh cm-2. The use of C-doped g-C3N4microspheres as a 3D Li host shows promising results for stable lithium deposition without dendrite formation.

Adipose-derived stem cell/FGF19-loaded microfluidic hydrogel microspheres for synergistic restoration of critical ischemic limb.

The efficacy of stem cell therapy is substantially compromised due to low cell survival rate and poor local retention post-delivery. These issues drastically limit the application of stem cells for ischemic limb therapy, which requires effective blood perfusion and skeletal muscle regeneration. Herein, based on microfluidic technology, an integrated stem cell and cytokine co-delivery system designed for functional ischemic limb salvage was constructed by first incorporating the myogenic cytokine, fibroblast growth factor 19 (FGF19), into microspheres composed of methacrylate gelatin (GelMA). Then adipose-derived stem cells (ADSCs) were highly absorbed into the porous structure of the microspheres, overcoming the insufficient loading efficiency and activities by conventional encapsulation strategy. The fabricated ADSCs/FGF19@µsphere system demonstrated a uniform size of about 180 µm and a highly porous structure with pore sizes between 20 and 40 µm. The resultant system allowed high doses of ADSCs to be precisely engrafted in the lesion and to survive, and achieved sustained FGF19 release in the ischemic region to facilitate myoblast recruitment and differentiation and myofibrils growth. Furthermore, the combination of ADSCs and FGF19 exhibited a positive synergistic effect which substantially improved the therapeutic benefit of angiogenesis and myogenesis, both in vitro and in vivo. In summary, a stem cell and cytokine co-delivery system with the properties of easy preparation and minimal invasiveness was designed to ensure highly efficient cell delivery, sustained cytokine release, and ultimately realizes effective treatment of ischemic limb regeneration.

Optimisation of the Flame Spheroidisation Process for the Rapid Manufacture of Fe3O4-Based Porous and Dense Microspheres.

The rapid, single-stage, flame-spheroidisation process, as applied to varying Fe3O4:CaCO3 powder combinations, provides for the rapid production of a mixture of dense and porous ferromagnetic microspheres with homogeneous composition, high levels of interconnected porosity and microsphere size control. This study describes the production of dense (35-80 µm) and highly porous (125-180 µm) Ca2Fe2O5 ferromagnetic microspheres. Correlated backscattered electron imaging and mineral liberation analysis investigations provide insight into the microsphere formation mechanisms, as a function of Fe3O4/porogen mass ratios and gas flow settings. Optimised conditions for the processing of highly homogeneous Ca2Fe2O5 porous and dense microspheres are identified. Induction heating studies of the materials produced delivered a controlled temperature increase to 43.7 °C, indicating that these flame-spheroidised Ca2Fe2O5 ferromagnetic microspheres could be highly promising candidates for magnetic induced hyperthermia and other biomedical applications.

Colorimetric porous microspheres of natural sodium alginate for chilled pork visual monitoring.

Chilled meat is subject to deterioration by various factors during storage and distribution. Therefore, it is very important to monitor the quality of meat in real time. This study aims at preparing a natural, low-cost indicating microsphere to visualize the freshness of meat by the combination of sodium alginate (SA) and chitosan with 0-10 wt% anthocyanins derived from chokeberry as a colorant using ionic gelation method. Size-controlled porous SA microspheres with were further constructed by freeze-drying and their physicochemical properties were characterized by SEM, FTIR, DSC, and XRD. Results showed that microspheres with 1 wt% anthocyanin showed good responsiveness to different concentrations of ammonia and were able to effectively identify the freshness of chilled meat by color change. Principal component analysis showed that the color difference of the porous microspheres was highly significantly correlated with pH, TVB-N, total plate count and thiobarbituric acid active substance (p < 0.01), suggesting a visible satisfactory capability of the microspheres to identify the spoilage in pork. Principal component analysis showed that the color difference of the porous microspheres was highly significantly correlated with pH, TVB-N, total plate count and thiobarbituric acid active substance (P < 0.01), suggesting a visible satisfactory capability of the microspheres to identify the spoilage in pork.

Development of a porous layer-by-layer microsphere with branched aliphatic hydrocarbon porogens.

Porous polymer microspheres are employed in biotherapeutics, tissue engineering, and regenerative medicine. Porosity dictates cargo carriage and release that are aligned with the polymer physicochemical properties. These include material tuning, biodegradation, and cargo encapsulation. How uniformity of pore size affects therapeutic delivery remains an area of active investigation. Herein, we characterize six branched aliphatic hydrocarbon-based porogen(s) produced to create pores in single and multilayered microspheres. The porogens are composed of biocompatible polycaprolactone, poly(lactic-co-glycolic acid), and polylactic acid polymers within porous multilayered microspheres. These serve as controlled effective drug and vaccine delivery platforms.

Fabrication of Graphdiyne/Graphene Composite Microsphere with Wrinkled Surface via Ultrasonic Spray Compounding and its Microwave Absorption Properties.

Advanced carbon materials are constantly being used in the field of microwave absorption. Herein, in order to enrich the variety and expand the application fields of graphdiyne (GDY), the wrinkled graphene (RGO) nanosheet coated and embedded with GDY porous microspheres (RGO/GDY) are prepared by GDY synthesis, ultrasonic spray, and pyrolysis. The study finds that RGO and GDY have effective synergistic effects. The suitable pores and composition, conductive network formed by overlapping 0D and 2D materials, special surface and internal morphology design, and high-temperature activation process make RGO/GDY exhibit excellent impedance matching and attenuation capabilities. Under the best amount of GDY (20 mg), the particle sizes of the microspheres (≈6 µm), and filler content (27.5%), the minimum reflection loss (RLmin ) is -58 dB@8.3 GHz, and the corresponding matching thickness is 2.7 mm. The effective absorption bandwidth is 4.3 GHz as the thickness is 1.9 mm. By adjusting the thickness, the absorber can completely absorb microwaves of all the C, X, and Ku bands. The microwave absorbing mechanisms are elucidated. GDY materials are first applied to the field of microwave absorption, enhancing the absorption performance of RGO/GDY. It provides a new way to manufacture electromagnetic wave absorbers with satisfactory performance.

Fabrication of magnesium-doped porous polylactic acid microsphere for bone regeneration.

Biodegradable polymer microspheres that can be used as drug carriers are of great importance in biomedical applications, however, there are still challenges in controllable preparation of microsphere surface morphology and improvement of bioactivity. In this paper, firstly, poly(L-lactic acid) (PLLA) was synthesised by ring-opening polymerisation under anhydrous anaerobic conditions and further combined with the emulsion method, biodegradable PLLA microspheres (PM) with sizes ranging from 60-100 µm and with good sphericity were prepared. In addition, to further improve the surface morphology of PLLA microspheres and enhance their bioactivity, functionalised porous PLLA microspheres loaded with magnesium oxide (MgO)/magnesium carbonate (MgCO3) (PMg) were also prepared by the emulsion method. The results showed that the loading of MgO/MgCO3 resulted in the formation of a porous structure on the surface of the microspheres (PMg) and the dissolved Mg2+ could be released slowly during the degradation of microspheres. In vitro cellular experiments demonstrated the good biocompatibility of PM and PMg, while the released Mg2+ further enhanced the anti-inflammatory effect and osteogenic activity of PMg. Functionalised PMg not only show promise for controlled preparation of drug carriers, but also have translational potential for bone regeneration.

Monodisperse Porous Silica/Polymer Nanocomposite Microspheres with Tunable Silica Loading, Morphology and Porosity.

Hybrid organic/inorganic nanocomposites combine the distinct properties of the organic polymer and the inorganic filler, resulting in overall improved system properties. Monodisperse porous hybrid beads consisting of tetraethylene pentamine functionalized poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) particles and silica nanoparticles (SNPs) were synthesized under Stoeber sol-gel process conditions. A wide range of hybrid organic/silica nanocomposite materials with different material properties was generated. The effects of n(H2O)/n(TEOS) and c(NH3) on the hybrid bead properties particle size, SiO2 content, median pore size, specific surface area, pore volume and size of the SNPs were studied. Quantitative models with a high robustness and predictive power were established using a statistical and systematic approach based on response surface methodology. It was shown that the material properties depend in a complex way on the process factor settings and exhibit non-linear behaviors as well as partly synergistic interactions between the process factors. Thus, the silica content, median pore size, specific surface area, pore volume and size of the SNPs are non-linearly dependent on the water-to-precursor ratio. This is attributed to the effect of the water-to-precursor ratio on the hydrolysis and condensation rates of TEOS. A possible mechanism of SNP incorporation into the porous polymer network is discussed.