Zhentan Lu

Hierarchically Three-Dimensional Nanofiber Based Textile with High Conductivity and Biocompatibility As a Microbial Fuel Cell Anode

Microbial fuel cells (MFCs) encompass complex bioelectrocatalytic reactions that converting chemical energy of organic compounds to electrical energy. Improving the anode configuration is thought to be a critical step for enhancing MFCs performance. In present study, a hierarchically structured textile polypyrrole/poly(vinyl alcohol-co-polyethylene) nanofibers/poly(ethylene terephthalate) (referred to PPy/NFs/PET) is shown to be excellent anode for MFCs. This hierarchical PPy/NFs/PET anode affords an open porous and three-dimensional interconnecting conductive scaffold with larger surface roughness, facilitating microbial colonization and electron transfer from exoelectrogens to the anode. The mediator-less MFC equipped with PPy/NFs/PET anode achieves a remarkable maximum power density of 2420 mW m(-2) with Escherichia coli as the microbial catalyst at the current density of 5500 mA m(-2), which is approximately 17 times higher compared to a reference anode PPy/PET (144 mW m(-2)). Considering the low cost, low weight, facile fabrication, and good winding, this PPy/NFs/PET textile anode promises a great potential for high-performance and cost-effective MFCs in a large scale.

The woven fiber organic electrochemical transistors based on polypyrrole nanowires/reduced graphene oxide composites for glucose sensing

Novel woven fiber organic electrochemical transistors based on polypyrrole (PPy) nanowires and reduced graphene oxide (rGO) have been prepared. SEM revealed that the introduction of rGO nanosheets could induce the growth and increase the amount of PPy nanowires. Moreover, it could enhance the electrical performance of fiber transistors. The hybrid transistors showed high on/off ratio of 102, fast switch speed, and long cycling stability. The glucose sensors based on the fiber organic electrochemical transistors have also been investigated, which exhibited outstanding sensitivity, as high as 0.773 NCR/decade, with a response time as fast as 0.5s, a linear range of 1nM to 5μM, a low detection concentration as well as good repeatability. In addition, the glucose could be selectively detected in the presence of ascorbic acid and uric acid interferences. The reliability of the proposed glucose sensor was evaluated in real samples of rabbit blood. All the results indicate that the novel fiber transistors pave the way for portable and wearable electronics devices, which have a promising future for healthcare and biological applications.

Hydrogel degradation triggered by pH for the smart release of antibiotics to combat bacterial infection

Here we developed a hydrogel that could be triggered by a change in pH to degrade and smartly release antibiotics to combat a bacterial infection; use of this hydrogel could reduce the inappropriate and disproportionate use of antibiotics.

Concurrent filtration and inactivation of bacteria using poly(vinyl alcohol-co-ethylene) nanofibrous membrane facilely modified using chitosan and graphene oxide

Integrating multiple nanoscale components with antibacterial properties into a single membrane filter is indispensable for efficient application in water treatment. Herein, we prepare a poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibrous membrane (NFM) decorated using chitosan (CS) and graphene oxide (GO), via a melt-phase-separated nanofiber/CS-GO suspension coating technique. As indicated by morphology and structure analysis, CS and GO have tight physical attachment to the surface of the nanofibers throughout the PVA-co-PE layer, with diminished pore size and contact angle. Compared to commercial PVDF membrane, NFMs exhibit enhanced retention rate of pigmented nanoparticles and bacterial cells and higher and more stable water flux due to their relatively small thickness and high stacking density. The performance for inactivation of bacteria is also improved by employing NFM. Particularly after CS/GO modification, the inactivation rate of the membrane is increased to the range of 97.8–99.5% against E. coli and S. aureus with superior repetitive-use performance. These results can be attributed to the enhancement effect of the nanofiber network on the activity of the hydroxyl groups in PVA-co-PE, NH3+ in chitosan and the 2D structure of graphene oxide. The present membranes have much potential for use in long-term water treatment with high efficiency and stability.

Vancomycin-hybrid bimetallic Au/Ag composite nanoparticles: preparation of the nanoparticles and characterization of the antibacterial activity

We report vancomycin-hybrid bimetallic nanoparticles (Au/AgNPs@Van) that can adhere to bacterial surfaces with high antibacterial activity. The Ag/AuNPs@Van also show weaker bacterial drug resistance than free vancomycin, and have a low cytotoxicity. Ag/AuNPs@Van has a promising future in the treatment of infectious diseases.

Affinity functionalization of PVA-co-PE nanofibrous membrane with Ni(II)-chelated ligand for bovine hemoglobin adsorption

We report that poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibrous membrane was surface functionalized by iminodiacetic acid (IDA) and then chelated by Ni(II) ions for hemoglobin adsorption. The results indicated that bovine hemoglobin (BHb) adsorption on Ni(II)-chelated PVA-co-PE nanofibrous membrane was better described by the Langmuir model. The experimental maximum adsorption capacity value was 66 mg g−1. The method performed in this study provides an exploratory research for the large-scale purification of BHb and other proteins.

Photosensitizer–AgNP composite with an ability to selectively recognize pathogen and enhanced photodynamic efficiency

BODIPY-functionalized glycopolymer-modified AgNPs were prepared as a PDT agent. The agent was “smart”, i.e., it could distinguish pathogens from normal cells, and showed a photodynamic efficiency three times greater than that of free photosensitizer under the same light intensity. The work is a good attempt to make a new generation of PDT agents for antibacterial applications.

Facile fabrication of poly(glycidyl methacrylate)-b-polystyrene functional fibers under a shear field and immobilization of hemoglobin

Poly(glycidyl methacrylate)-b-polystyrene (PGMA-b-PS) block copolymers were synthesized by two steps with 1,1-diphenylethylene (DPE) as the chain transfer reagent. The molecular weights and chemical structures of block copolymers were characterized by GPC, FTIR and NMR analyses. Then PGMA-b-PS fibers were fabricated under a shear field using methanol as the antisolvent and glycerin as the shear medium. The shear speed, the concentration of block copolymer solution and the ratios of methanol to glycerin were controlled and regulated. The morphologies of block copolymer fibers were investigated by SEM. Finally, immobilization of bovine hemoglobin on block copolymer fibers was carried out which has potential applications in blood substitutes.

Antibacterial and rechargeable surface functional nanofiber membrane for healthcare textile application

Nosocomial cross infection (NCI) seriously threatens human health, causing enormous economic loss. There is a critical need for new healthcare textiles to prevent NCI. Herein, a polymer modified nanoscale porous membrane was prepared by surface graft polymerization. The membrane had excellent antibacterial activity, and the antibacterial activity could be recharged through a simple method. And the membrane had a high filtration rate against bacteria. Excellent antibacterial activity and a high filtration rate mean the membrane could protect users from direct and indirect contact with pathogens, preventing the spread of diseases with the aid of textiles. The successful preparation of an anti-NCI membrane also provides a universal method for exploring nanoscale porous membrane materials as healthcare textiles to block NCI in hospitals.

A novel PU/PVA-co-PE composite nanofiber membrane for water filtration

Filter membranes with high efficiency and low energy consumption are gaining more attention owing to the increase in water pollution. To enhance the filtration performance, a novel spindle polyurethane (PU) / poly(vinyl alcoholco-ethylene) (PVA-co-PE) composite nanofiber membrane was prepared. It is the first time that the spindle composite nanofibers and nanofiber membranes are prepared based on the PU/PVA-co-PE/CAB (cellulose acetate butyrate) immiscible polymer blends. The effects of PU concentration on the morphology, size distribution, and hydrophilicity of PU/PVA-co-PE nanofiber membranes were analyzed. The pure PVA-co-PE nanofiber membrane and PU/PVA-co-PE composite nanofiber membranes were used to filtrate the nanoparticle suspension with scarlet pigments (50–300 nm). Due to the smaller pore size, looser structure, and larger porosity, the rejection rate and flux of spindle PU/PVA-co-PE composite nanofiber membranes are both higher than that of pure PVA-co-PE nanofiber membrane. When the basic weight of nanofiber layer is 6 g/m2, the rejection rate of all the PU/PVA-co-PE membranes are above 99%. This study provided a novel, facile, and high-throughput method to prepare spindle nanofiber membranes and indicated the advantage of spindle PU/PVA-co-PE composite nanofiber membranes in the application of water filtration.