(6eo) Nanobioelectronics in Healthcare: From Nanobots to Wearable Biosensors

The 1966 movie Fantastic Voyage captured the world's imagination, portraying a tiny submarine navigating through the human bloodstream and treating life-threatening medical conditions. Artificial micromotors, operating on locally supplied fuels and performing complex tasks, offer great potential for diverse biomedical applications to realize this vision, including autonomous delivery and release of therapeutic payloads and cell manipulation. During my PhD research in professor Joseph Wang’s group at UC San Diego, I developed a variety of artificial micro/nanobots based on different propulsion mechanisms including the fastest synthetic nanomachine to date: the polymer-based catalytic tubular microengine displays very efficient propulsion of over 1000 body length/s. The microengines modified with different functional groups or bio-receptors can selectively isolate specific target (such as protein, DNA, bacteria and cancer cells) from complex media. Newly-developed biocompatible and biodegradable microbots can move autonomously in natural biofluids without additional chemical fuels, holding great promise for in vivo biomedical applications: the polyaniline/zinc microrockets display effective propulsion in acidic environments (such as human stomach); Mg-based Janus micromotors, which utilize macrogalvanic corrosion and pitting corrosion processes, can be powered by salt water. The first in vivo study of artificial microbots is demonstrated in a living organism using a mouse model. The acid-driven propulsion in the stomach effectively enhances the binding and retention of the motors as well as of cargo payloads on the stomach wall. The body of the motors gradually dissolves in gastric acid, autonomously releasing their carried payloads, leaving nothing toxic behind. These works are anticipated to significantly advance the emerging field of nano/microbots and to open the door to in vivo evaluation and clinical applications of these synthetic motors.

While nanobots offer great promise to efficiently deliver the drug payloads and perform diagnosis inside human body, wearable devices are able to realizing personalize medicine externally through non-invasive continuous monitoring on the human skin. However, most currently developed wearable devices are capable only in tracking the physical activities of an individual and fail to provide insight into the individual’s state of health. My postdoc research in professor Ali Javey’s group at UC Berkeley focuses on the wearable biosensors for non-invasive health monitoring. A fully-integrated sensor array was developed and can serve as an ideal platform for a wide range of real-time healthcare monitoring such as exercise-induced dehydration and medical diagnosis.

With such innovations and developments, along with careful attention to key challenges and requirements, nanobioelectronics (from wearable biosensors to autonomous nanobots in human body) is expected to have tremendous impact on diverse biomedical applications from in vivo drug delivery to non-invasive health monitoring, providing unlimited opportunities limited only by one's imagination.