Synergistic integration of materials in medical microrobots for advanced imaging and actuation

Medical microrobotics capitalizes on smart materials to target specific body sites effectively, precisely and locally, thus holding promise to revolutionize precision medicine in the future. Advances in material science and microfabrication or nanofabrication techniques have facilitated the implementation of a myriad of functionalities into microrobots. Efficient navigation and monitoring of microrobots within the highly dynamic and often inaccessible environment of living mammalian tissues is paramount for their effective in vivo applications and eventual clinical translation. This need calls for the deployment of biomedical imaging modalities with adequate sensitivity, penetration depth and spatiotemporal resolution, as well as for efficient integration of biocompatible contrast materials into microrobots. In this Review, we discuss emerging approaches for multiplexed imaging and actuation of microrobots within complex biological environments, focusing on the synergistic combination of responsive and contrasting materials to achieve desired morphological and functional properties, in vivo visibility and biosafety. The convergence between microrobotics and biomedical imaging paves the way for a new generation of medical microrobots enabling the use of energy for both mechanical actuation and efficient monitoring of their activity in vivo.