Translational prospects of untethered medical microrobots

Untethered mobile microrobots have the potential to transform medicine radically. Their small size and wireless mobility can enable access to and navigation in confined, small, hard-to-reach, and sensitive inner body sites, where they can provide new ways of minimally invasive interventions and targeted diagnosis and therapy down to the cellular length scales with high precision and repeatability. The exponential recent progress of the field at the preclinical level raises anticipations for their near-future clinical prospects. To pave the way for this transformation to happen, however, the formerly proposed microrobotic system designs need a comprehensive review by including essential aspects that a microrobot needs to function properly and safely in given in vivo conditions of a targeted medical problem. The present review provides a translational perspective on medical microrobotics research with an application-oriented, integrative design approach. The blueprint of a medical microrobot needs to take account of microrobot shape, material composition, manufacturing technique, permeation of biological barriers, deployment strategy, actuation and control methods, medical imaging modality, and the execution of the prescribed medical tasks altogether at the same time. The incorporation of functional information pertaining each such element to the physical design of the microrobot is highly dependent on the specific clinical application scenario. We discuss the complexity of the challenges ahead and the potential directions to overcome them. We also throw light on the potential regulatory aspects of medical microrobots toward their bench-to-bedside translation. Such a multifaceted undertaking entails multidisciplinary involvement of engineers, materials scientists, biologists and medical doctors, and bringing their focus on specific medical problems where microrobots could make a disruptive or radical impact.