An implantable antibacterial drug-carrier:Mesoporous silica coatings with size-tunable vertical mesochannels

Implant-associated bacterial infection remains one of the most common and serious complications.Therefore,a surface boasting long-term antibacterial ability for implants is highly desirable.Herein,mesoporous silica coatings(MSCs)with vertical and size-tunable mesochannels are fabricated on a variety of metal substrates via a nano-interfacial oriented assembly approach.Such facile and versatile approach relies on the vertically oriented fusion of composite micelles on the nanoscale flatness surface of substrates.Such orientation assembly process endows the MSCs with vertical mesochannels,tunable mesopore size(ca.5.5-13.5 nm),and switchable substrates even with complex and diversified surfaces.Importantly,the MSCs on titanium substrates(Ti@MSCs)exhibit excellent performances for drug adsorption and sustained release.The saturation adsorption capacity can reach 0.544 μg·cm^(-2) towards minocycline hydrochloride(MC-HCl)antibiotic molecules,which is 6.5 times as the bare titanium(Ti)substrate.In addition,the drug release time can be controlled from 84 to 216 h by simply adjusting the mesopore size.As a proof of concept,the Ti@MSCs can realize a higher antibacterial rate(95.9%),compared with the bare Ti(70.3%).The results highlight the high potential of MSCs as implant coating for long-term preventing and eliminating peri-implantitis.

Vertically ordered silica mesochannels as preconcentration materials for the electrochemical detection of methylene blue

Silica mesochannels(SMCs) vertically and regularly oriented to the surface of indium tin oxide(ITO) electrodes were prepared and utilized for preconcentration and detection of methylene blue(MB) in aqueous solution. The positively charged MB can be adsorbed to the SMCs by following the pseudo-first-order kinetic model. The negative value of ?G=?34.73 k J/mol derived from the Langmuir adsorption isotherm indicated the thermodynamic feasibility of the adsorption and the spontaneous nature of the process. Moreover, the adsorbed MB can undergo an electrochemical reaction on the ITO electrode at a suitable potential and the resulting electrical current can be utilized to quantify the MB in aqueous solution. A good analytical performance for MB with a linear range from 10 nmol/L to 1.0 ?mol/L and a detection limit at the nmol/L level was obtained. We believe that such a platform consisting of SMCs perpendicularly tethered to the underlying electrode surface simultaneously allows enrichment and electrochemical detection and can be extended for the detection of various charged dyes, as well as many other charged species.

Growing vertical aligned mesoporous silica thin film on nanoporous substrate for enhanced degradation,drug delivery and bioactivity

Mesoporous silica thin film has been widely used in various fields,particularly the medical implant coating for drug delivery.However,some drawbacks remain with the films produced by traditional method(evaporation-induced self-assembly,EISA),such as the poor permeability caused by their horizontal aligned mesochannels.In this study,the vertical aligned mesoporous silica thin film(VMSTF)is uniformly grown alongside the walls of titania nanotubes array via a biphase stratification growth method,resulting in a hierarchical two-layered nanotubular structure.Due to the exposure of opened mesopores,VMSTF exhibits more appealing performances,including rapid degradation,efficient small-molecular drug(dexamethasone)loading and release,enhanced early adhesion and osteogenic differentiation of MC3T3-E1 cells.This is the first time successfully depositing VMSTF on nanoporous substrate and our findings suggest that the VMSTF may be a promising candidate for bone implant surface coating to obtain bioactive performances.

Bioprocess-inspired preparation of silica with varied morphologies and potential in lithium storage

As one of the most delicate bioprocesses in nature,biosilicification is closely related to biosilica with various morphologies,and has provided abundant inspiration to materials synthesis.In the present study,to explore the biosilica formation process and fabricate silica with an exquisite microstructure for lithiumion battery(LIB)electrodes,a bacterial phage(M13)is used as a biotemplate to synthesize silica with diverse morphologies:cylinders,hexagonal prisms,assemblies of smaller cylinders and nanowires.A facile ethanol bath method is conducted to coat the nanowires with nitrogen-containing carbon and carbon-coated SiO_(2) nanowires with mesochannels(C@msSiO_(2) NWs)are first used as anode materials for LIBs.Attributed to the uniform carbon coating and parallel mesochannel structure,the electronic conductivity and capacity to accommodate volume variations were significantly improved.In the electrochemical perfo rmance test,the composites calcined at 750℃(C@msSiO_(2) NWs-750)show an impressive capacity of 653 mA h g^(-1) at a current density of 500 mA g^(-1) and stability(1000 cycles).In view of the electrochemical test outcomes,the prepa ration of a sophisticated structure with an outstanding potential is easily achieved via a biomimetic strategy.