Synthesis of Macro-Mesostructured γ-Al_2O_3 with Large Pore Volume and High Surface Area by a Facile Secondary Reforming Method

Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the reaction temperature, the first aging temperature and the second aging temperature, were investigated. The textural properties of γ-Al2O3 were characterized by means of N2 adsorption-desorption isotherms, X-ray powder diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FTIR） spectroscopy and thermogravimetry （TG）. The experimental results indicated that AACH and amorphous A1OOH were the precursors of alumina, which were formed via precipitation from solutions after reaction of aluminum sulphate with ammonium hydrogen carbonate. The precursor nanocrystallites grew and re-assembled during the secondary reforming process, which resulted in an increased pore size and pore volume and a decreased bulk density. The as-synthesized γ-Al2O3 materials featured meso/macroporosity, large pore volume （2.175 cm^3/g）, high surface area （237.8 m^2/g）, and low bulk density （0.284 g/mL）.

The self-assembly of gold nanoparticles in large-pore ordered mesoporous carbons

Simple encapsulation of 3 nm gold nanoparticles in ordered mesoporous carbon with large pores of 17 nm and thick pore walls of 16 nm was achieved by a metal–ligand coordination assisted-selfassembly approach.Polystyrene-block-polyethylene-oxide(PS-b-PEO)diblock copolymer with a large molecular weight of the PS chain and mercaptopropyltrimethoxysilane were used as the template and the metal ligand,respectively.Small-angle X-ray scattering,X-ray diffraction,transmission electron microscopy,and X-ray photoelectron spectroscopy showed that monodispersed aggregation-free gold nanoparticles approximately 3 nm in size were partially embedded in the large open pore structure of the ordered mesoporous carbon.The strong coordination between the gold species and the mercapto groups and the thick porous walls increased the dispersion of the gold nanoparticles and essentially inhibited particle aggregation at 600℃.The gold nanoparticles in the ordered mesoporous carbon are active and stable in the reduction of nitroarenes involving bulky molecules using sodium borohydride as a reducing agent under ambient conditions(30℃)in water.The large interconnected pore structure facilitates the mass transfer of bulky molecules.

Monodisperse Ultra-Large-Pore Silica Coated Polystyrene Core-Shell Microbeads via Layer-by-Layer Assembly for Nano-Micro Composite

Polystyrene （PS） @SiO2 core-shell microbeads with large pore and large particle size were prepared via layer-by-layer（LBL）assembly technique for potential applications in nano-micro composites. Negative silica nanoparticles synthesized via modified St6ber method and cationic poly （diallyldimethylammonium chloride） were alternately adsorbed on the surface of microbeads. Zeta potential, size, and morphology of the microbeads were monitored during LBL assembly process to ensure the successful deposition of silica nanoparticles. The porous shell was characterized using nitrogen adsorption and desorption analyses, and the surface area, volume and diame- ter of the pores were derived. It is found that the porous shell thickness and the pore size can be tuned by changing the coating times of silica nanoparticles. Finally, PS@SiO2 core-shell microbeads with 5 grn PS solid core and 350 nm mesoporous shell （mean BJH pore diameter is ~27 nm） were used to load CdSe/ZnS quantum dots （QDs）. The fluorescence microscopic image and the optical amplification of the QDs-embedded microbeads （QDBs） indicate that the as-prepared core-shell microbeads can provide adequate space for QDs and may be useful for further application of nano-micro composites.

A novel synthesis of highly active and highly stable non-noble-nickel-modified persulfated Al_(2)O_(3)@ZrO_(2) core-shell catalysts for n-pentane isomerization

The non-noble metal modified sulfated zirconia was found easy to deactivate.Herein,highly active and highly stable non-noble core-shell Ni-S_(2)O_(8)^(2−)/Al_(2)O_(3)@ZrO_(2) catalysts(Ni-SA@Z-x,x=Al content in wt%)have been successfully prepared and investigated for n-pentane isomerization.The results showed that the core-shell Ni-SA@Z-30 provided a sustained high isopentane yield(63.1%)with little or no deactivation within 5000 min at a mild reaction pressure of 2.0 MPa,which can be attributed to the following factors:(i)carbon deposition was greatly suppressed by the large pore size and huge pore volume;(ii)the loss of sulfur entities was suppressed because the small and highly dispersed tetragonal ZrO_(2) particles can bond with the S species strongly;(iii)strong Brønsted acidity can be maintained well after the isomerization.The pore structures and acid nature of the core-shell Ni-SA@Z-x are entirely different from those of the normal structure Ni-S_(2)O_(8)^(2−)/ZrO_(2)-Al_(2)O_(3),even though the Al content and the compositions of the individual components are the same.The Al_(2)O_(3)cores endow the catalysts with high internal surface area and high mechanical strength.Meanwhile,the ZrO_(2) shell,which consists of more and smaller tetragonal ZrO_(2) particles because of the large surface area of the Al_(2)O_(3)core,promotes the formation of more stable sulfur species and stronger binding sites.

Leukocyte/platelet hybrid membrane-camouflaged dendritic large pore mesoporous silica nanoparticles co-loaded with photo/chemotherapeutic agents for triple negative breast cancer combination treatment

Triple-negative breast cancer(TNBC)is an aggressive subset of breast cancer and currently lacks effective therapeutic targets.As two main phototherapeutic methods,photothermal therapy(PTT)and photodynamic therapy(PDT)show many advantages in TNBC treatment,and their combination with chemotherapy can achieve synergistic therapeutic effects.In the present study,a biomimetic nanoplatform was developed based on leukocyte/platelet hybrid membrane(LPHM)and dendritic large pore mesoporous silicon nanoparticles(DLMSNs).A near infrared(NIR)fluorescent dye IR780 and a chemotherapeutic drug doxorubicin(DOX)were co-loaded into the large pores of DLMSNs to prepare DLMSN@DOX/IR780(DDI)nanoparticles(NPs),followed by camouflage with LPHM to obtain LPHM@DDI NPs.Through the mediation of LPHM,LPHM@DDI NPs showed an excellent TNBC-targeting ability and very high PTT/PDT performances in vitro and in vivo.Upon NIR laser irradiation,LPHM@DDI NPs exhibited synergistic cytotoxicity and apoptosis-inducing activity in TNBC cells,and effectively suppressed tumor growth and recurrence in TNBC mice through tumor ablation and anti-angiogenesis.These synergistic effects were sourced from the combination of PTT/PDT and chemotherapy.Altogether,this study offers a promising biomimetic nanoplatform for efficient co-loading and targeted delivery of photo/chemotherapeutic agents for TNBC combination treatment.

Cell Membrane-camouflaged Multi-functional Dendritic Large Pore Mesoporous Silica Nanoparticles for Combined Photothermal Therapy and Radiotherapy of Cancer

Combining photothermal therapy and radiotherapy(PTT-RT) with reducing tumor hypoxia acts as an important antitumor modality. However, it is a great challenge to realize photothermal therapy, radiotherapy and exogenous oxygen supply in one nanosystem. To realize a combination of the three functions, we fabricated a red blood cell membrane(RBCm)-camouflaged, red blood cell content(RBCc) and the copper sulfide(CuS) co-loaded dendritic large pore mesoporous silica nanoparticle(DLMSN/CuS/RBCc/ RBCm). The cell membrane coating endowed the nanoparticles with good stability in the physiological environment, and CuS allowed the nanoparticle exhibiting good photothermal and radiosensitization properties. RBCc loaded nanoparticle DLMSN/CuS/RBCc enhanced superior anti-tumor effect than DLMSN/CuS during combined PTT-RT therapy because the introduction of RBCc increased the exogenous oxygen supply. The in vitro study further demonstrated that the combination of photothermal therapy and radiotherapy induced superior antitumor efficacy than single therapy. Our work thus presents a unique multifunctional nanoscale platform favorable for combined PTT and RT.

Near-field electrospun PCL fibers/GelMA hydrogel composite dressing with controlled deferoxamine-release ability and retiform surface for diabetic wound healing

Wound ulceration caused by diabetes is a typical chronic wound wherein healing the local tissue is difficult due to lack of blood vessels and tissue necrosis caused by the long-term accumulation of free radicals.Near-field electrospinning(NFES)is an innovative technology used to produce micro-nano-scaled,controllable sequencing fibers.In this study,we constructed a novel wound dressing based on the NFES polycaprolactone(PCL)fiber network and modified gelatin with methacrylic anhydride(GelMA)hydrogel to promote angiogenesis and the re-epithelialization of diabetic wounds.An angiogenic and antioxidant drug named deferoxamine(DFO)was encapsulated in a GelMA hydrogel to achieve a slow-release effect that is more suitable for chronic wounds.The cell adhesion experiment showed that the cells could attach to the fibers in the dressing group having a network of PCL fibers on the surface and grow along the direction of the fibers,which in turn,effectively regulates cell behavior from the physical structure.Additionally,the large pore size(~500μm)of the network allowed the cells to penetrate the pores and enter the surface of the hydrogel without being blocked out.Besides,the composite dressing had a notable effect on angiogenesis.Furthermore,antioxidation experiments confirmed that the DFO-loaded hydrogel exhibited antioxidant activity.Experimental animal models of diabetes showed that rats treated with the PCL-GelMA-DFO(PGD)hydrogel had faster ability of hemostasis,scab formation,and wound healing.In conclusion,the PGD hydrogel effectively promoted the repair of chronic wounds.

Rational design of imine-linked three-dimensional mesoporous covalent organic frameworks with bor topology

Three-dimensional(3D)covalent organic frameworks(COFs)possess great potential applications in various fields.Constructing 3D COFs with large pore sizes is extremely challenging due to the interpenetration and collapse.Herein,we report a series of crystalline imine-linked 3D COFs(3D-bor-COF-1,3D-borCOF-2,3D-bor-COF-3)with mesoporous channels through rationally designing the topology configuration.These 3D-bor-COFs display permanent porosity and Brunauer–Emmett–Teller(BET)surfaces of 3205.5,1752.7,and 2077.3 m2 g−1(SLangmuir=4277.7,2480.3,and 2698.0 m2 g−1),respectively.The pore sizes of 3Dbor-COFs were confirmed by the lattice fringes from high-resolution transmission electron microscopy,as well as structural simulation and nitrogen adsorption isotherm analysis.3D-bor-COFs display large pore sizes(3.8 nm for 3D-borCOF-3),which is among the highest record of 3D COFs.Owing to the unstackedaromatic pore environment and high specific surface area,3D-bor-COFs display excellent adsorption capacity for benzene vapor(1203.9 mg g−1 for 3D-bor-COF-3)under 298 K,which is three times higher than that of the best-reported 2D COF.This work not only provides inspiration for designing 3D mesoporous imineCOFs,but also demonstrates a strategy for constructing aromatics adsorption materials.