Near infrared photothermal-responsive poly(vinyl alcohol)/black phosphorus composite hydrogels with excellent on-demand drug release capacity

Owing to their excellent tissue-penetration ability, near-infrared (NIR) photothermal-responsive intelligent materials show remarkable advantages in biomedical applications. However, the majority the previously reported NIR-absorbing agents are metal- and carbon-based nanoparticles, both of which possess low photothermal conversion efficiency and poor biocompatibility. Herein, polydopamine modified black phosphorus (pBP) nanosheet-containing poly(vinyl alcohol) (PVA) composite hydrogels are facilely fabricated via a freezing/thawing approach. Taking advantage of the high photothermal conversion efficiency of pBP, the prepared composite hydrogels exhibit a fascinating on-demand NIR-responsive drug release behavior. An in vitro cell culture study demonstrates that these composite hydrogels present good biocompatibility and cellular interaction. Moreover, since the incorporated pBP nanosheets can form a strong hydrogen bonding interaction within the PVA matrix, the composite hydrogels also show enhanced mechanical properties. We believe that the robust mechanical properties and excellent biocompatibility accompanied by the highly controllable NIR-responsive drug release performance of the obtained composite hydrogel augur well for its diverse future applications in the biomedical field.