This manuscript describes the accurate deposition of carbon on the surface of ZnO nanorods by a simple, microwave-assisted method and the studies on the cytotoxicity and photocatalytic activity of the C/ZnO hybrids. For the coating of carbon, the surface of the preformed ZnO nanorods were first modified by amino groups and then grafted by glucose, and finally they were irradiated in a microwave field to induce the transformation of glucose into carbon. With this method, the as-prepared carbon-coated product preserved the good dispersity and uniformity of the initial ZnO nanorods. Studies on the effects of carbon-coated ZnO nanorods and pure ZnO nanorods on cultured mouse fibroblast cells revealed that the coating of biocompatible carbon remarkably reduced the cytotoxicity of ZnO nanorods. In addition, benefiting from the synergy effect of carbon and ZnO, carbon-coated ZnO NRs also exhibited excellent photocatalytic activity toward the decomposition of methylene blue in a short time (approximately 14 min).

The progress of high-efficiency electrocatalysts toward the oxygen reduction reaction and oxygen evolution reaction (ORR and OER) is central to reproductive fuel cells and rechargeable metal–air batteries. Transition-metal-based catalysts with superb activity and stability are highly considered as an alternative of the present noble-metal-based electrocatalysts. Herein, we reported a simple construction of Mn-doped Co–N–C (Mn/Co–N–C) as an excellent bifunctional ORR/OER electrocatalyst. It is found that the enhanced ORR/OER electrocatalytic activity benefits by suitably doping Mn, which affects the electronic structure of the Co species. The optimized Mn/Co–N–C exhibits excellent ORR/OER performance with a potential difference of 0.86 V, which outperforms a commercial Pt/C electrocatalyst (0.93 V). Rechargeable liquid zinc–air batteries based on the Mn/Co–N–C bifunctional catalyst exhibit initial discharge and charge potentials at 1.20 and 2.02 V (5 mA cm–2), along with an outstanding stability with negligible increase in polarization even after 250 h. Furthermore, the all-solid-state zinc–air batteries fabricated with the Mn/Co–N–C bifunctional catalyst also display an outstanding lifetime with 60 cycles (2 mA cm–2) and steady charge/discharge potential even upon bending.

We herein proved that the two commonly used antithrombotic methods, heparin loading and pre-endothelialization could both greatly enhance the patency rate of a small-diameter graft in a canine model. Tubular grafts having an inner diameter of 4 mm were prepared by electrospinning poly(l-lactide-co-ε-caprolactone) (P(LLA-CL)) and heparin through a coaxial electrospinning technique. Seventy-two percent of heparin was found to be released sustainably from the graft within 14 days. To prepare the pre-endothelialized grafts, we seeded endothelial cells isolated from the femoral artery and cultured then dynamically on the lumen until a cell monolayer was formed. Digital subtraction angiography (DSA) and color Doppler flow imaging (CDFI) were used to monitor the patency without sacrificing the animals. Histological analyses revealed that following the direction of blood flow, a cell monolayer was formed at the proximal end of the heparin-loaded grafts, but such a monolayer could be found in the middle or distal region of the grafts. In contrast, the whole luminal surface of the pre-endothelialized graft was covered by a cell monolayer, suggesting the in vivo survival of the preseeded cells. This demonstrated that heparin was a comparatively simple method to achieve good patency, but the pre-endothelialization had better mechanical properties and cellular compatibility.

Electrospinning is a new method used in tissue engineering. It can spin fibers in nanoscale by electrostatic force. A series of thermoplastic polyurethane (TPU)/collagen blend nanofibrous membranes was prepared with different weight ratios and concentrations via electrospinning. The two biopolymers used 1,1,1,3,3,3,-hexafluoro-2-propanol (HFP) as solvent. The electrospun TPU-contained collagen nanofibers were characterized using scanning electron microscopy (SEM), XPS spectroscopy, atomic force microscopy, apparent density and porosity measurement, contact-angle measurement, mechanical tensile testing and viability of pig iliac endothelial cells (PIECs) on blended nanofiber mats. Our data indicate that fiber diameter was influenced by both polymer concentration and blend weight ratio of collagen to TPU. The average diameter of nanofibers gradually decreases with increasing collagen content in the blend. XPS analysis indicates that collagen is found to be present at the surface of blended nanofiber. The results of porosity and contact-angle measurement suggest that with the collagen content in the blend system, the porosity and hydrophilicity of the nanofiber mats is greatly improved. We have also characterized the molecular interactions in TPU/collagen complex by Fourier transform infrared spectroscopy (FT-IR). The result could demonstrate that there were no intermolecular bonds between the molecules of TPU and collagen. The ultimate tensile stress and strain were carried out and the data confirmed the FT-IR results. The TPU/collagen blend nanofibrous mats were further investigated as promising scaffold for PIEC culture. The cell proliferation and SEM morphology observations showed that the cells could not only favorably grow well on the surface of blend nanofibrous mats, but also able to migrate inside the scaffold within 24 h of culture. These results suggest that the blend nanofibers of TPU/collagen are designed to mimic the native extracellular matrix for tissue engineering and develop functional biomaterials.