Fig. 2: Photo-thermo response of the AuNP-containing anisotropic hydrogel.

a Schematic for the fabrication of anisotropic hydrogel after incorporating AuNPs into the precursor solution. b Absorption spectra of the aqueous suspension of AuNPs, anisotropic hydrogels with and without AuNPs. c Variations of localized temperature of the gel under the irradiation of 520 nm green light with different power intensity. d, e Photos (d) and variations of the localized temperature and gel dimensions (e) to show the reversible anisotropic deformation of the AuNP-containing hydrogel under cyclic irradiation of green light with the intensity of 3.7 W cm−2. Scale bar in d is 1 cm.