Triboelectric liquid volume sensor for self-powered lab-on-chip applications

Abstract

Technology for enabling drug delivery with precise control is strongly demanded by patients with diabetes or other chronic diseases. More intelligent functions such as drug loading and delivery in controllable manner without requiring electrical power will make low-cost drug delivery patches come true. One of the promising candidates is triboelectric technology which has been deployed as nanogenerators and self-powered glucose sensors recently. In this paper, the drug delivery is triggered by finger-pressing on a polymer based micropump. Considering that the finger-pressing should be an action of very low frequency, e.g., 1 to 2Hz, triboelectric energy harvester (TEH) based on contact-separation mode between patterned biocompatible polymer layer and Aluminum (Al) film is integrated with microneedles on a flexible skin patch. Leveraging triboelectric materials and compatible fabrication technology, we successfully develop a self-powered flexible skin patch for transdermal insulin delivery with novel liquid volume sensor to monitor delivered drug volume and flexible energy harvester using the same triboelectric mechanism. With 3stacked polymer layers, the TEH of 2×2cm2 area generates 33μW by gentle finger tapping at 2Hz. Such energy could be harvested even during drug delivery via finger pressing. In future we can further store harvested energy in a battery to provide required operation power for other active components or glucose sensors integrated in this skin patch. The developed flexible skin patch for transdermal drug delivery is further validated by in vivo experiments in rats.