Fig. 4: Demonstration of functional nanowhisker glues.

a Schematic depicting the on-demand photothermal therapy experimental setup. b Maximum temperature at the central hotspot of where the laser hits the skin-gel interface using an IR thermal camera. c Representative temperature profiles after around 280 s laser irradiation. d Recorded maximum temperature of laser-irradiating hotspots. The samples were irradiated for 300 s, then the laser is shut off for 30 s, and turned on for 30 s to reveal the speed of temperature fluctuation. e Schematic showing the sonodynamic effect of ChsNWs, which generate reactive oxygen species (ROS) under the field of a clinically used therapeutic ultrasound. f Fluorescence intensity of the ROS probe (DCFH) after different times of ultrasound treatment. g Schematic showing when the ROS probe encapsulated in a hydrogel as a mock prodrug (representing the drug caged by a ROS cleavable functional group), and then implanted under the skin, the ultrasound can penetrate a depth of skin and activate the prodrug through the sonodynamic effect of ChsNWs. h Confocal images before and after ultrasound activation, showing 5 min of ultrasound activates the prodrug reflected by the intense fluorescence at the interface; experiments were independently repeated at least three times with similar results. Data in (f)are presented as mean ± SD (n = 3). Figures in (e, g) are created with BioRender.com.