A flexible GaN light-emitting diode (LED) has been fabricated on a liquid crystal polymer (LCP) substrate for biomedical applications. The bending radius and fatigue tests demonstrated the mechanically and optically stable characteristics of the GaN LEDs on the flexible substrates. A white light-emitting phosphor-coated GaN LED showed its potential as a next-generation flexible light source. A water-resistant and biocompatible polytetrafluoroethylene (PTFE) coated flexible LED detected prostate-specific antigen (PSA), which is expected to be used in future biomedical devices. (C) 2011 Elsevier Ltd. All rights reserved.