Porous Microspheres Comprising CoSe2 Nanorods Coated with N-Doped Graphitic C and Polydopamine-Derived C as Anodes for Long-Lived Na-Ion Batteries

Metal–organic framework-templated nitrogen-doped graphitic carbon(NGC)and polydopaminederived carbon(PDA-derived C)-double coated one-dimensional CoSe_(2) nanorods supported highly porous threedimensional microspheres are introduced as anodes for excellent Na-ion batteries,particularly with long-lived cycle under carbonate-based electrolyte system.The microspheres uniformly composed of ZIF-67 polyhedrons and polystyrene nanobeads(φ=40 nm)are synthesized using the facile spray pyrolysis technique,followed by the selenization process(P-CoSe_(2)@NGC NR).Further,the PDA-derived C-coated microspheres are obtained using a solution-based coating approach and the subsequent carbonization process(P-CoSe_(2)@PDA-C NR).The rational synthesis approach benefited from the synergistic effects of dual carbon coating,resulting in a highly conductive and porous nanostructure that could facilitate rapid diffusion of charge species along with efficient electrolyte infiltration and effectively channelize the volume stress.Consequently,the prepared nanostructure exhibits extraordinary electrochemical performance,particularly the ultra-long cycle life stability.For instance,the advanced anode has a discharge capacity of 291(1000th cycle,average capacity decay of 0.017%)and 142 mAh g^(-1)(5000th cycle,average capacity decay of 0.011%)at a current density of 0.5 and 2.0 A g^(-1),respectively.

Bioinspired porous microspheres for sustained hypoxic exosomes release and vascularized bone regeneration

Exosomes derived from mesenchymal stem cells(MSCs)have demonstrated regenerative potential for cell-free bone tissue engineering,nevertheless,certain challenges,including the confined therapeutic potency of exosomes and ineffective delivery method,are still persisted.Here,we confirmed that hypoxic precondition could induce enhanced secretion of exosomes from stem cells from human exfoliated deciduous teeth(SHEDs)via comprehensive proteomics analysis,and the corresponding hypoxic exosomes(H-Exo)exhibited superior potential in promoting cellular angiogenesis and osteogenesis via the significant up-regulation in focal adhesion,VEGF signaling pathway,and thyroid hormone synthesis.Then,we developed a platform technology enabling the effective delivery of hypoxic exosomes with sustained release kinetics to irregular-shaped bone defects via injection.This platform is based on a simple adsorbing technique,where exosomes are adsorbed onto the surface of injectable porous poly(lactide-co-glycolide)(PLGA)microspheres with bioinspired polydopamine(PDA)coating(PMS-PDA microspheres).The PMS-PDA microspheres could effectively adsorb exosomes,show sustained release of H-Exo for 21 days with high bioactivity,and induce vascularized bone regeneration in 5-mm rat calvarial defect.These findings indicate that the hypoxic precondition and PMS-PDA porous microsphere-based exosome delivery are efficient in inducing tissue regeneration,hence facilitating the clinical translation of exosome-based therapy.

Surface Treatment and Biomimetic Mineralization of Porous Microspheres Fabricated by Calcium Gluconate-g-Poly(D,L-lactide)

Porous hybrid microspheres were fabricated by the synthesized calcium gluconate-g-poly（D,L-lactide） （CG-g- PDLLA） composites. These hybrid microspheres were treated with an alkaline solution for different period of time to control the amount of generated carboxylate groups and remained CG on the surface. The microspheres were then incubated in a supersaturated simulated body fluid （1.5 SBF） solution for different time to investigate their biomimetic mineralization behavior. The depositions were found to have a fine cluster morphology, a similar crystal structure and chemical structure to natural hydroxyapatite, and a medium Ca/P of approximately 1.30. The effect of surface treating time on the structure and mineralization behavior of these microspheres has been discussed in detail. The results indicate that the nucleation and growth of apatite on the surface are influenced by the induced carboxylate groups and the remained CG. The hybrid CG-g- PDLLA microspheres have the potential as a novel alternative in bone tissue engineering.

Hollow TiO2-x porous microspheres composed of wellcrystalline nanocrystals for high-performance lithiumion batteries

Hollow TiO2-x porous microspheres consisted of numerous well-crystalline nanocrystals with superior structural integrity and robust hollow interior were synthesized by a facile sol-gel template-assisted approach and two-step carbonprotected calcination method, together with hydrogenation treatment. They exhibit a uniform diameter of -470 nm with a thin porous wall shell of -50 nm in thickness. The Brunauer-Emmett-Teller （BET） surface area and pore volume are -19 m2/g and 0.07 crnB/g, respectively. These hollow TiOR_x porous microspheres demonstrated excellent lithium storage performance with stable capacity retention for over 300 cycles （a high capacity of 151 mAh/g can be obtained up to 300 cycles at I C, retaining 81.6% of the initial capacity of 185 mAh/g） and enhanced rate capability even up to 10 C （222, 192, 121, and 92.1 mAh/g at current rates of 0.5, 1, 5, and 10 C, respectively）. The intrinsic increased conductivity of the hydrogenated TiO2 microspheres and their robust hollow structure benefidal for lithium ion-electron diffusion and mitigating the structural strain synergistically contribute to the remarkable improvements in their cycling stability and rate 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 60-100μm 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(MgCO_(3))(PMg)were also prepared by the emulsion method.The results showed that the loading of MgO/MgCO_(3)resulted in the formation of a porous structure on the surface of the microspheres(PMg)and the dissolved Mg^(2+)could be released slowly during the degradation of microspheres.In vitro cellular experiments demonstrated the good biocompatibility of PM and PMg,while the released Mg^(2+)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.

Multispectral ErBO_(3)@ATO porous composite microspheres with laser and electromagnetic wave compatible absorption

The high-speed advances in electromagnetic(EM)wave and laser detection technology have accelerated the innovation of absorbing materials toward specific multi-band compatibility.It is difficult to achieve dual absorption of EM waves and near-infrared lasers by absorbing materials in a single frequency band;the design of high-performance laser-EM wave multi-band compatible absorbing materials is imminent.Herein,ErBO_(3)@ATO(erbium borate/antimony-doped tin oxide)porous composite microspheres with an average size of 15-20μm are produced solvothermal method and self-assembly,which exhibit excellent laser-EM wave compatible absorption.The porous structure on the surface of ErBO_(3)microspheres provides heterogeneous nucleation sites for ATO particle deposition.The minimum reflectivity of the composite for1.06 and 1.54μm lasers is 9.59%and 4.79%,which is0.57%and 3.78%lower than those of pure ATO particles,respectively.The composites containing 70 wt%porous ErBO_(3)@ATO reveal the minimum reflection loss(RL)value of-31.6 dB,and an effective absorption band width reaches 2.08 GHz at 2.5 mm thickness.The mechanism of near-infrared laser and EM wave compatible absorption is the synergistic effect of the energy level transition of ErBO_(3)and the dielectric loss of ATO,coupled with the large surface area and porous structure of the micro spheres.Therefore,the designed porous ErBO_(3)@ATO composite microspheres can be an attractive choice for lasers and EM wave high-quality compatible absorption.

MoSe_(2)/TiO_(2)heterostructure integrated in N-doped carbon nanosheets assembled porous core-shell microspheres for enhanced sodium storage

Engineering the structure and composition of electrode materials is one of the essential means for achieving excellent electrochemical performance.The rational design of Na+host materials is still a massive challenge for sodium ion batteries(SIBs).Herein,MoSe_(2)/TiO_(2)heterostructure is integrated with N-doped carbon nanosheets to assemble into hierarchical flowerlike porous core-shell microspheres(MoSe_(2)/TiO_(2)@N-C),which is firstly reported by room-temperature stirring coupled with vulcanization treatment.The cavity of the core-shell structure could provide enough storage space for Na+and alleviate the volume expansion during charge/discharge processes.The apertures between nanosheets provide a guarantee for the rapid penetration of electrolyte to enhance the utilization rate of electrode materials.Furthermore,building heterostructures by combining different phase structures can facilitate electron transfer and accelerate reaction kinetics.Benefiting from the synergistic contributions of structure and composition,MoSe_(2)/TiO_(2)@N-C as SIBs anode material shows better reversible capacities of 302.5 mAh·g^(-1)at 1 A·g^(-1)for 400 cycles and 217.4 mAh·g^(-1)at 4 A·g^(-1)for 900 cycles.Strikingly,the reversible capacities can be restored entirely to the initial level after a high current density cycle.

Fabrication of three-dimensional porous La-doped SrTiO3 microspheres with enhanced visible light catalytic activity for Cr（VI） reduction

In recent years, much effort has been focused on the development of the photocatalysts with high performance under visible light irradiation. In this paper, three-dimensional porous La-doped SrTiO3 （LST） micro- spheres were prepared by a modified sol-gel method, in which the agarose gel/SrCO3 microsphere and La2O3 were employed as the template and the La resource, respectively. The as-prepared LST microspheres exhibit a porous structure with a diameter of about 10 μm and a surface pore size of about 100 nm. The La element was doped into the crystal lattice of SrTiO3 by the substitution of La^3＋ for Sr^2＋. Therefore, the absorption edge of LST samples shifts toward the visible light region, and their photocatalytic activity for the Cr（VI） reduction is enhanced under visible light. Among all LST samples, LST-0.5 （the La^3＋ doping content is 0.5 wt-%） exhibited the highest visible-light photocatalytic activity, which can reduce 84% Cr（VI） within 100 rain. This LST materials may become a promising photocatalyst for the facile treatment of waste- water containing poisonous heavy metal ions.

Preparation of PLGA Microspheres with Different Porous Morphologies

Poly（D,L-lactide-co-glycolide）（PLGA） microspheres were prepared by emulsion solvent evaporation method. The influences of inner aqueous phase, organic solvent, PLGA concentration on the morphology of microspheres were studied. The results showed that addition of porogen or surfactants to the inner aqueous phase, types of organic solvents and polymer concentration affected greatly the microsphere morphology. When dichloromethane was adopted as organic solvent, microspheres with porous structure were produced. When ethyl acetate served as organic solvent, two different morphologies were obtained. One was hollow microspheres with thin porous shell under a lower PLGA concentration, another was erythrocyte-like microspheres under a higher PLGA concentration. Three types of microspheres including porous, hollow core with thin porous shell（denoted by hollow in brief） and solid structures were finally selected for in vitro drug release tests. Bovine serum albumin（BSA） was chosen as model drug and encapsulated within the microspheres. The BSA encapsulation efficiency of porous, hollow and solid microspheres was respectively 90.4%, 79.8% and 0. And the ultimate accumulative release was respectively 74.5%, 58.9% and 0. The release rate of porous microspheres was much slower than that of hollow microspheres. The experiment results indicated that microspheres with different porous structures showed great potentials in controlling drug release behavior.

Preparation of Porous Polylactide Microspheres and Their Application in Tissue Engineering

In this study, porous polylactide（PLA） microspheres with different structures were prepared through the multiple emulsion solvent evaporation method. By changing organic solvents（ethyl acetate and chloroform） and adding effervescent salt NH4 HCO3 in the inner water phase, microspheres with porous capsular, matrix, microcapsular and multivesicular structures were prepared. The protein encapsulation and release, and the cell growth behavior of porous microspheres were further explored. Under the same inner water phase, microspheres prepared with chloroform had higher protein encapsulation efficiency and less protein release rate as compared with those prepared with ethyl acetate. Cell experiments showed that the relatively rough surface of microspheres prepared with chloroform was more favorable for the cell growth in comparison with the smooth surface of microspheres prepared with ethyl acetate. This study shows a simple and effective method to control the protein release and cell growth behaviors of polymer microspheres by tuning their porous structure.

Preparation of porous polyimide microspheres by thermal degradation of block copolymers

A new preparation method has been developed for thermally stable porous polyimide microspheres. Porous polyimide microspheres were prepared using trib]ock copolymers that consisted of a thermally stable polyimide derived from pyromellitic dianhydride/4,4＇-oxydianiline as the continuous phase and a thermally labile polyether as the dispersed phase. Spheres of copolymers were generated in a nonaqueous emulsion and then gradually heated to complete the imidization to form a microphase-separated structure. Subsequently, thermal treatment at a slightly reduced pressure removed the labile blocks and produced pores. Under suitable decomposition conditions, the pore size of the porous polyimide was in the range of 200-400nm.

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.

Macroporous-mesoporous C-,S-,N-doped titania microspheres via the polyHIPE microspheres templates

Doping and increasing specific surface area by forming highly porous structures are two effective ways to enhance the photocatalytic performances of TiO_(2) particles.He re for the first time,we report a new facile method to prepare the macroporous-mesoporous C-,S-,N-doped TiO_(2)(C/S/N-TiO_(2))microspheres via polyHIPE microsphe res as templates.The chemical and crystalline structure s of these hierarchical porous TiO_(2) microspheres are analyzed with FTIR,XPS,EDS,and XRD.The macroporous-mesoporous structures are confirmed with SEM observation and BET analysis.UV-vis DRS spectra analysis shows that the band gaps of C doped TiO_(2),C/N doped TiO_(2),C/S doped TiO_(2) and C/S/N doped TiO_(2) are estimated to be 3.07,3.01,2.94 and 2.81 eV,respectively,which are significantly narrower than that of TiO_(2) nanoparticles(3.23 eV).Photoluminescence spectra demonstrate that the recombination of electrons and holes in these macroporous-mesoporous TiO_(2) microspheres is also suppressed.The hierarchical porous C/S/N-TiO_(2) microspheres show high visible-light catalytic efficiency and excellent cycling stability to degrade RhB dye.

Facile preparation of hierarchical porous polydopamine microspheres for rapid removal of chromate from the wastewater

Cr(Ⅵ)containing industrial wastewaters are highly toxic and carcinogenic,and severely threats living creatures and the environment.Therefore,it is highly desired yet challenging to develop an available and economical adsorbent for simultaneously detoxifying Cr(Ⅵ)anions to Cr(Ⅲ)ions and removing them from the wastewater.Here we propose a facile method for rapid removal of Cr(Ⅵ)ions from the wastewater by using a synthetic polydopamine microsphere(PPM)adsorbent with hierarchical porosity.The as-prepared PPM exhibits high Cr(Ⅵ)removal capacity of 307.7 mg/g and an outstanding removal efficiency.They can effectively decrease the Cr(Ⅵ)concentration to lower than 0.05 mg/L well below the limits for drinking water standard of WHO regulations in 60 s at pH 2.More importantly,PPMs can reduce the lethal Cr(Ⅵ)anions to Cr(Ⅲ)ions with low toxicity,and simultaneously immobilize them on the matrices of PPMs.

微液滴限域合成和调控空心多孔Ir基电解水催化剂及其传质促进作用

Maximally exploiting the active sites of iridium catalysts is essential for building low-cost proton exchange membrane(PEM)electrolyzers for green H_(2)production.Herein,we report a novel microdrop-confined fusion/blasting(MCFB)strategy for fabricating porous hollow IrO_(1-x)microspheres(IrO_(1-x)-PHM)by introducing explosive gas mediators from a NaNO_(3)/glucose mixture.Moreover,the developed MCFB strategy is demonstrated to be general for synthesizing a series of Ir-based composites,including Ir-Cu,Ir-Ru,Ir-Pt,Ir-Rh,Ir-Pd,and Ir-Cu-Pd and other noble metals such as Rh,Ru,and Pt.The hollow structures can be regulated using different organics with NaNO_(3).The assembled PEM electrolyzer with IrO_(1-x)-PHM as the anode catalyst(0.5 mg/cm^(2))displays an impressive polarization voltage of 1.593and 1.726 V at current densities of 1 and 2 A/cm^(2),respectively,outperforming commercial IrO_(x)catalysts and most of the ever-reported iridium catalysts with such low catalyst loading.More importantly,the breakdown of the polarization loss indicates that the improved performance is due to the facilitated mass transport induced by the hollowness.This study offers a versatile platform for fabricating efficient Irbased catalysts for PEM electrolyzers and beyond.

Tumor‑Anchoring Drug‑Loaded Fibrous Microspheres for MR Imaging‑Guided Local Chemotherapy and Metastasis Inhibition

Unobtrusive metastasis and invasion of malignant tumors are major causes for the death of cancer patients,and unfortunately the lack of specificity and abrupt release of anticancer drugs applied to the primary tumors are causing serious side effects in cancer management.Hence,the development of controlled local drug delivery systems that can effectively treat primary tumors and inhibit tumor metastasis is of critical importance for improved cancer therapeutics.Herein,we developed hyaluronic acid(HA)-modified porous fibrous microspheres as a drug delivery system with the functions of long-acting local chemotherapy,tumor metastasis inhibition and magnetic resonance(MR)imaging.Poly(lactic-co-glycolic acid)(PLGA)short fibers obtained by combined electrospinning and homogenization techniques were successfully modified with gadolinium(Gd^(3+))chelates and HA,which were subsequently mixed with doxorubicin(DOX)to obtain the multifunctional drug-loaded fibrous microspheres of DOX-PLGA-PEI-DTPA-Gd/HA(DOX−PGH)by electrospray and further crosslinking.The developed DOX−PGH microspheres with an average diameter of 118.8μm possess good structural stability and a high r1 relaxivity,and can achieve long-term DOX release.The cellular and animal experiments demonstrated that the DOX−PGH microspheres could facilitate targeted delivery of DOX to accelerate 4T1 cell death while reducing cancer cell metastasis due to the cooperative actions of long-term DOX-mediated chemotherapy and the fibrous microsphere-induced tumor anchoring to likely avoid primary tumor cell shedding,and render MR imaging of tumors during the treatment.The developed DOX−PGH microspheres may represent one of the updated local tumor chemotherapy formulations for improved tumor therapy with justified antitumor and anti-metastasis efficacy.