Development of a Biodegradable Green Emitter Chitosan-Based OLED for Implantable Biomedical Devices.

Light is a crucial tool in medicine for diagnosis and treatment. New light sources called organic light-emitting devices (OLEDs) have been integrated with various extracorporeal and implantable devices to sense or stimulate specific cellular responses. However, one of the current challenges remaining is to design a transient OLED that functions effectively and completely dissolves inside the human body when it is no longer needed, without affecting homeostasis. This work addresses this issue by creating the first transient chitosan-based OLED. The OLED is turned on at low voltages and emits a bright green light with a maximum luminance of 36 cd/m(2). In vitro assays showed that all layers break down under physiological settings, and the biocompatibility was confirmed by in vivo tests. The chitosan-based OLED represents a breakthrough in transient electronics and advances implantable light-based biomedical applications.