Temperature-sensitivity and cell biocompatibility of freeze-dried nanocomposite hydrogels incorporated with biodegradable PHBV

The structure, morphology, thermal behaviors and cytotoxicity of novel hydrogels, composed of poly(N-isopropylacrylamide)(PNIPAM) and biodegradable polyester poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) under nanoclay hectorite “Laponite XLG” severed as physical cross-linker, were characterized by X-ray diffraction, scanning electron microscopy, gravimetric method, differential scanning calorimetry, and cell culture experiments. It was found that, due to the introduction of hydrophobic PHBV, the homogeneity of interior pore in the pure PNIPAM nanocomposite hydrogel was disrupted, the transparency and swelling degree gradually decreased. Although the weight ratio between PHBV and NIPAM increased from 5 to 40 wt.%, the volume phase transition temperature (VPTTs) of hydrogel were not altered compared with the pure PNIPAM nanocomposite hydrogel. No matter what PHBV content, the PHBV/PNIPAM/Hectorite hydrogels always exhibit good stimuli-responsibility. In addition, human hepatoma cells(HepG2) adhesion and spreading on the surface of PHBV-based hydrogels was greatly improved than that of pure PNIPAM nanocomposite hydrogel at 37 °C due to the introduction of PHBV.