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• Medina-Sánchez, Mariana
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• Schmidt, Oliver G.

Abstract

Micromotors are devices that operate at the microscale and convert energy to motion. Many micromotors are microswimmers, i.e., devices that can move freely in a liquid at a low Reynolds number, where viscous drag dominates over inertia. Hybrid biomicromotors are microswimmers that consist of both biological and artificial components, i.e., one or several living microorganisms combined with one or many synthetic attachments. Initially, living microbes were used as motor units to transport synthetic cargo at the microscale, but this simple allocation has been altered and extended gradually, especially considering hybrid biomicromotors for biomedical in vivo applications, i.e., for non-invasive microscale operations in the body. This review focuses on these applications, where other properties of the microbial component, for example, the capability of chemotaxis, biosensing, and cell-cell interactions, have been exploited in order to realize tasks like localized diagnosis, drug delivery, or assisted fertilization in vivo. In the biohybrid approach, biological and artificially imposed functionalities act jointly through a microrobotic device that can be controlled or supervised externally. We review the development and state-of-the-art of such systems and discuss the mastery of current and future challenges in order to evolve hybrid biomicromotors from apt swimmers to adapted in vivo operators.