Fabrication, microstructure, in vitro biocompatibility, and drug delivery property of titania nanotube-assembled hollow microfibers

Hollow microfibers (HMFs) are extensively employed as cell-supporting matrices in the biomedical applications. In this study, titania nanoparticle (NP) HMFs and titania nanotube (NT) HMFs were synthesized and their microstructure, in vitro biocompatibility and drug delivery property were investigated. Titania NP HMFs were first synthesized using gelatin fibers as sacrificial templates via a sol-gel route and then in situ hydrothermally transformed to titania NT HMFs. The resulting HMFs were systematically characterized by FE-SEM, TEM, XRD, FT-IR, XPS, and N₂ adsorption–desorption techniques. SEM observations show that titania NP HMFs had diameters of 50–200 µm and were constructed by numerous titania NPs with diameters of 50–100 nm, while titania NT HMFs had similar diameters and were constructed by numerous titania NTs with diameters of 10–20 nm. The formation of titania NTs made titania NT HMFs with a nanofibrous surface architecture. TEM observations show that each titania NT had a hollow structure. XRD patterns indicate that titania NT HMFs consisted of both rutile and anatase titania phases. Both types of HMFs showed good biocompatibility and supported adhesion and proliferation of osteoblast MC3T3-E1 cells on their surfaces. Compared to titania NP HMFs, titania NT HMFs enhanced cell adhesion and proliferation due to their nanofibrous surface architectures. Additionally, titania NT HMFs also showed higher drug loading efficiency for tetracycline hydrochloride (model drug) and maintained the biological efficiency of tetracycline hydrochloride against the growth of Escherichia coli. The present titania NT HMFs have the potential as drug-laden cell-supporting matrices.