Fig. 2: Nanoscale characterization of the nanowhisker glue.

a, b TEM micrographs of microtomography slices of hydrogel on skin using ChsNWs without ultrasound. White dashed lines indicate the boundary between ChsNW and skin or hydrogel, while ChsNWs are labeled with white arrows. c TEM micrograph of the interface found in (b, no ultrasound) and its associated EDS mapping with counts of Au signal (lower). d, e TEM micrographs of microtomography slices of hydrogel on skin using ChsNWs with ultrasound, where the boundaries and ChsNWs are labeled with white dashed lines and white arrows, respectively. f TEM micrograph of the interface found in (e) ultrasound, and its associated EDS mapping with counts of Au signal (lower). g–j High magnification TEM micrographs: bare hydrogel, hydrogel-ChsNWs network, ChsNWs network, ChsNWs network-skin. Experiments in (a–j) were independently repeated at least three times with similar results. k Schematics of the interactions between ChsNWs (green), hydrogel (blue), and tissue (orange), as well as the three parts of the hydrogel-nanowhisker-skin interface (right).