Natural Wax for Transient Electronics

Emerging classes of bioresorbable electronic materials serve as the basis for active biomedical implants that are capable of providing sensing, monitoring, stimulating, and other forms of function over an operating period matched to biological processes such as wound healing. These platforms are of interest because subsequent dissolution, enzymatic degradation, and/or bioresorption can eliminate the need for surgical extraction. This report introduces natural wax materials as long-lived, hydrophobic encapsulation layers for such systems, where biodegradation eventually occurs by chain scission. Studies of wax stability as an encapsulation material demonstrate the ability to retain operation of underlying biodegradable electronic systems for durations between a few days to a few weeks during complete immersion in aqueous solutions in ex-vivo physiological conditions. Electrically conductive composites result from the addition of tungsten micro/nanoparticles, as a conductive, printable paste with similar lifetimes. Demonstrations of these materials in partially biodegradable wireless light-emitting diodes and near-field communication circuits illustrate their use in functional bioresorbable electronic systems. Investigations in animal models reveal no signs of toxicity or other adverse biological responses.