The sense of touch is one of our most vital but poorly understood senses. In humans, the degradation of touch sensation with age, disease, and drug treatments is a debilitating and costly problem. Touch, hearing, pain sensation, and balance all depend upon mechanotransduction, which is the conversion of a mechanical stimulus to an electrical signal. Mechanotransduction is difficult to study due to the very small forces involved, and we are using our expertise in microelectromechanical systems (MEMS) to engineer new tools to study the senses of touch and hearing.

Our ability to study touch in mammals is limited, so instead we turn to one of our genetic relatives, Caenorhabditis elegans. This small, soil-dwelling worm has been used to study mechanotransduction for the past 30 years. We seek to understand the biomechanics of touch sensation at the organism, cellular, and molecular levels. Our initial work focused on characterizing the sense of touch of whole animals, but this soon led to studies of touch-receptor neurons and even individual proteins. We developed a variety of MEMS tools to carry out this work. Arrays of microscale pillars form an environment littered with force-sensing obstacles for investigating worm locomotion and behavior. Specialized MEMS cantilevers precisely apply and sense microscale forces. These cantilevers enable force clamps, a useful tool that applies a constant force to an object. In concert with patch clamps, a standard means of studying the electrical properties of cells, force clamps provide an ideal way to investigate the role of ion channels in sensing forces. Using these tools in collaboration with biology labs here at Stanford, we hope to uncover the biological pathway for touch sensation.