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A general phenomenon that electrospun polymer nanofibers self-assemble into honeycomb-patterned nanofibrous structures (HNFSs) is reported. We used electrospinning to produce charged polymer nanofibers, which were kept in liquid state (wet) on landing on the substrates by appropriately controlling the electrospinning conditions. Driven by the competitive actions of surface tension and electrostatic repulsion, these charged wet nanofibers self-assemble into the HNFSs. Fabrication of the well-defined three-dimensional HNFSs was successfully demonstrated for three different polymers, that is, polyacrylonitrile, polyvinyl alcohol, and polyethylene oxide. The pore diameter of the obtained honeycomb structures spans a wide range from micrometers to over 200 μm with depths as large as over 150 μm. The pore walls are composed of uniaxially aligned polymer nanofibers.

Photoelectrocatalysis (PEC) incorporates electrochemical techniques with photocatalysis (PC) to facilitate the separation of the photoelectron-hole produced at semiconductor nanoparticles, leading to enhanced photocatalytic efficiency for various applications. Due to its inherently low cost, non-toxicity and chemical stability, titanium dioxide (TiO2) based PEC devices are considered the most promising system for chemical engineering such as pollution degradation and fuel generation, and PEC sensing. In an attempt to bridge fundamental research and practical applications in chemical engineering and sensing, we herein systematically review recent advances in these PEC systems of different scales. More importantly, we offer a series of rational strategies including cell design, application of electric field photoelectrode morphology manipulation and bandgap engineering to enhance the performance of TiO2-based PEC devices and accelerate the commercialization of the TiO2-based PEC technology in chemical engineering.

Modifying the surface of the transmucosal area is a key research area because this process positively affects the three functions of implants: attachment to soft tissue, inhibiting bacterial biofilm adhesion, and the preservation of the crestal bone. To exploit the potential of titania nanotube arrays (TNTs) with or without using bovine serum albumin (BSA) to modify the surface of a dental implant in contact with the transmucosal area, BSA was loaded into TNTs that were fabricated by anodizing Ti sheets; the physical characteristics of these arrays, including their morphology, chemical composition, surface roughness, contact angle, and surface free energy (SFE), were assessed. The effect of Ti surfaces with TNTs or TNTs-BSA on human gingival fibroblasts (HGFs) was determined by analyzing cell morphology, early adhesion, proliferation, type I collagen ( COL-1 ) gene expression, and the extracellular secretion of COL-1. The results indicate that early HGF adhesion and spreading behavior is positively correlated with surface characteristics, including hydrophilicity, SFE, and surface roughness. Additionally, TNT surfaces not only promoted early HGF adhesion, but also promoted COL-1 secretion. BSA-loaded TNT surfaces promoted early HGF adhesion, while suppressing late proliferation and COL-1 secretion. Therefore, TNT-modified smooth surfaces are expected to be applicable for uses involving the transmucosal area. Further study is required to determine whether BSA-loaded TNT surfaces actually affect closed loop formation of connective tissue because BSA coating actions in vivo are very rapid.