Light-to-Heat Photothermal Dynamic Properties of Polypyrrole-Based Coating for Regenerative Therapy and Lab-on-a-Chip Applications

Targeted delivery and release of biomolecules, e.g., bone morphogenetic protein (BMP‐2), are gaining high interest due to the application for tissue engineering, diagnostics, surface‐enhanced therapy and lab‐on‐a‐chip. Here, a new hybrid temperature‐responsive system consisting of polypyrrole (PPy) layer, mesoporous titania surface (TMS), and BMP‐2 is proposed. The PPy layer has the light‐to‐heat photothermal property. Dynamic behavior of the PPy layer in response to light can regulate release of BMP‐2. The PPy‐based coatings on TMS have shown to be efficient for storage of BMP‐2 and can be tuned to release BMP‐2 under irradiation. Moreover, the possibility of local delivery and generation of a gradual release of BMP‐2 for regulated cell growth is shown. Furthermore, the fabricated surfaces possess excellent biocompatibility and low cytotoxicity for MC3T3‐E1 cells. It is shown that the released BMP‐2 can effectively promote osteogenic differentiation of MC3T3‐E1 cells. Thus, the TMS/PPy–BMP‐2 is suggested to prolong targeted release of the BMP‐2 for more than 25 days which stimulates osteoblasts’ proliferation. The new stimuli‐responsive hybrid system is promising for targeted, localized, sustained drug release and application in bone tissue engineering.