Photothermal Polymerization Using Graphene Oxide for Robust Hydrogelation with Various Light Sources.

Photopolymerization has been widely used for remote inducible hydrogelation with excellent spatiotemporal control. Recently, photothermal hydrogelation using near-infrared (NIR) light and photothermal agents has been developed showing remote hydrogelation ability with good biocompatibility and tissue penetration. However, the use of plasmonic nanoparticles (e.g., gold nanorods (GNRs)) still causes problems in reaction efficiency because hydrogelation is effective only when the wavelength of light is matched with the optical properties of the GNRs. Here, we demonstrated wavelength-independent photothermal hydrogelation using PEGylated graphene oxide (GO-PEG) that displays excellent heat generation from lights of a wide range of wavelengths. A sufficient increase in the temperature of the GO-PEG solution and the induction of thermal gelation of polyethylene diacrylate (PEGDA) by irradiation of various light sources (532, 785, and 980 nm) were demonstrated. Also, the GO-PEG-based photothermal hydrogelation of PEGDA was successfully employed for remote transdermal gel formation in vivo with 785 and 980 nm lasers. This wavelength-independent photothermal hydrogelation system will be useful for biomedical applications.