A novel thermoresponsive hydrogel composite controlled by infrared irradiation

In this study, we develop a novel hydrogel composite, which can perform sol–gel phase transitions under external stimulation. For biomedical applicability, near-infrared (NIR) irradiation was selected as the stimulant for phase transitions, because NIR is noninvasive for biological systems and can effectively penetrate them. To generate thermal energy from NIR, carbon nanotubes (CNTs) were chosen as they are known to have an effective light-to-thermal conversion property. Based on these considerations, polyacrylamide derivatives containing CNTs were adopted. The obtained gel exhibited alternating phase transitions behavior under NIR irradiation.