Collagen-Templated Bioactive Titanium Dioxide Porous Networks for Drug Delivery

A Type I collagen gel was used as a template for fabricating porous titanium dioxide networks. Conducting sol-gel chemistry within the template, followed by a mild solvothermal treatment (selected TiO2 collagen hybrids only), and then calcination to remove the template, produced anatase TiO2 porous networks composed of mesoporous fibers. The collagen morphology was retained. TiO2 fibers had walls up to 300 nm in thicluiess and hollow cores where the template was removed. Crystallite size, specific surface area (12.3-110 m(2) g(-1)), mesopore diameter (4.2-8.8 nm), and pore volume of the networks varied under different synthesis conditions; solvothermal treatment of the hybrid doubled the surface area and mesopore diameter of the final material. Biomineralization was studied by immersion in a simulated body fluid. All networks displayed in vitro bioactivity, and hence potential bone-bonding capability, with apatite clusters growing on the fibers. Drug delivery was assessed by the adsorption and release of anti-inflammatory ibuprofen. Ibuprofen was stored both at the fiber surface and in mesopores below 15 nm in diameter, while release was a sustained diffusion process. The network solvothermally treated as a hybrid adsorbed ibuprofen up to 58.9 mg g(-1). The TiO2 networks compared favorably with literature drug delivery vehicles when ibuprofen loading was normalized against surface area. Therefore, porous TiO2 networks have potential as materials for biomedical applications.