Fabrication and in vitro biocompatibility of hierarchical cellulose acetate/polyvinylpyrrolidone@titania nanowire hollow microfibers.

In this study, hierarchical cellulose acetate/polyvinylpyrrolidone hollow microfibers (CA/PVP HMFs) were first prepared via a dip coating method using a steel wire as tubular template and then supported a sol-gel deposition of titania nanoparticles (NPs) to derive CA/PVP@titania NP HMFs. After hydrothermally treated in NaOH solution, CA/PVP@titania NP HMFs were transformed to CA/PVP@titania nanowire (NW) HMFs. SEM observation showed that CA/PVP@titania NW HMFs had a hollow structure with diameters of 450-600 μm and exhibited a hierarchical and nanofibrous structure. Their surfaces were constructed by numerous titania NWs with diameters of 10-30 nm and lengths of 1-5 μm. The incorporation of PVP not only caused a significant change in surface wettability from hydrophobic CA HMFs to hydrophilic CA/PVP HMFs, but also promoted the sol-gel deposition of titania NPs on CA/PVP HMFs. CA/PVP@titania NW HMFs exhibited the highest hydrophilicity with water contact angle of 32° and the largest specific surface area of 86.1 m/g. In vitro biocompatible evaluation indicated that CA/PVP@titania NW HMFs exhibited much higher cell adhesion and proliferation than CA/PVP@titania NP HMFs and CA/PVP HMFs within 7 days due to the presence of nanofibrous surface architecture. Thus, the present CA/PVP titania NW HMFs have potential as biocompatible cell supporting matrices.