Microfabricated Structures for Evaluation of Tactile Sensitivity

A novel, sensitive, inexpensive test platform for rapid assessment of touch sensation is presented. The device translates basic research performed on the physiological properties of skin touch receptors into a clinical test for early diagnosis of diabetic and other types of neuropathy. The platform consists of a series of coin-shaped structures (550μm diameter, 1.5 to 30μm high) that a test subject attempts to feel by touch using a fingertip. The structures are made using a simple SU-8 process, standard lithography and dry etching. Early results show that there is some variability in sensitivity based on age, but "normal" subjects of most ages can readily detect bumps of heights below 5 microns, whereas subjects with neuropathy cannot. We believe that this new marker for tactile deficiency can rapidly be brought into clinical use. This paper demonstrates a successful collaborative project between a university microfabrication facility and a physician-led clinical study.