Bio-Integrated Microrobots: Fabrication, Actuation and Biomedical Applications

Bio-integrated microrobots (BIMs), which are fabricated with biofriendly materials, biological units (e.g. cells or biomolecules), or cell-material hybrids have emerged as a promising technology for minimally invasive biomedicine. The diminutive size and flexible structures enable BIMs to navigate within narrow, deep, and challenging-to-reach in vivo regions, performing biopsy, diagnostic, drug delivery, and therapeutic functions with minimal invasiveness. However, the clinical deployment of BIMs is a highly orchestrated task that requires consideration of material properties, structural design, locomotion, observation, therapeutic outcomes, and side effects on cells and tissues, etc. In this review, we review and discuss the latest advances in the bio-integrated microrobot domain, evaluating various methods associated with materials, fabrication, actuation, and the implementation of biomedical functions in BIMs. By comparing the advantages and shortcomings of these techniques, this review highlights the challenges and future trends in highly intelligent bio-integrated microrobots, which have huge potential in minimally invasive biomedicine.