Effect of titanium-doped bioactive glass on poly(2-hydroxyethyl methacrylate) hydrogel composites: Bioactivity, intermediate water, cell proliferation, and adhesion force

The intermediate water (IW) concept has been hypothesized to predict the biocompatibility of polymers and inorganic materials. This study, for the first time, prepared the composite biomaterials of poly(2-hydroxyethyl methacrylate) (PHEMA)/titanium-doped bioactive glasses (BGT) for bone regeneration by applying the IW concept. The homogeneous distribution of BGT and the mechanical stability of the composites were confirmed using X-ray diffraction, infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectrometry, and rheological characterization. In vitro tests with immersion in simulated body fluid showed that titanium doping improved the biomineralization properties. The IW level ranged from 10.4 wt% with 0% titanium doped to 25.6 wt% with 7.5% titanium doped. Cell viability tests on osteosarcoma cells revealed that the growth rate increased with increasing titanium concentration, reaching up to 150%. Based on single-cell force spectroscopy, an appropriate titanium concentration for cell adhesion was estimated to be 5%. The hydrated PHEMA gels with 5% BGT exhibited a high IW level of 19.3% and less hydrophilic wettability than the gels without titanium or with 10% BGT. The IW concept proved to be useful for predicting the bone regeneration potential on the interfaces of the PHEMA/BGT composite hydrogels.