Photothermally Triggered Shape-Adaptable 3D Flexible Electronics

Effective contact between flexible electronics and soft biological tissues, which may have different surface curvatures, for medical applications has long been a challenge. Here, this study reports a strategy for preparing shape-adaptable 3D flexible electronics by combining photothermally responsive poly(N-isopropylacrylamide)/gold nanorods (PNIPAM@AuNRs) composite hydrogels with conventional flexible microelectrode arrays (fMEAs). The fMEAs-functionalized composite hydrogels are shape-adaptable and can accommodate different surface geometries. Triggered remotely in seconds by near-infrared (NIR) light at a wavelength of 808 nm, the composite hydrogel layer is grafted on the back side of the fMEAs shrinks to induce a desirable shape transformation in the fMEAs. By patterning the responsive hydrogel layer, the fMEAs can exhibit planar-to-twisted structural transformations in response to an external stimulus as a result of differential shrinkage and their elastic moduli. This strategy not only enables fMEAs to modify their shape to remotely accommodate unpredictable shapes of different surfaces by irradiation with NIR but also provides multiple architectures of 3D fMEAs upon stimulation. These photothermally responsive composite-hydrogel-based fMEAs may provide new methods for achieving wearable and implantable devices and facilitate deeper investigations into biological systems.