A cross-linkable and resorbable PEDOT-based ink using a hyaluronic acid derivative as dopant for flexible bioelectronic devices

Abstract

Transient soft electronics that eliminate secondary surgery for device removal and enable effective integration into the body show great promise for diagnostic and therapeutic applications. Here, a novel cross-linkable and resorbable poly(3,4-ethylenedioxy)thiophene (PEDOT)-based ink using a hyaluronic acid (HA) derivative as dopant was designed and used to build a flexible and resorbable all-organic bioelectronic device. The HA derivative possesses structural features that enable it to degrade in few weeks, to serve as a dopant of PEDOT and to prepare water-resistant conductive patterns by photo-induced thiol-ene cross-linking. This cross-linking method, using poly(ethylene glycol) as crosslinker, afforded films with an initial conductivity of 0.6 S cm⁻¹, which could be enhanced up to 4.6 S cm⁻¹ after successive wetting/drying cycles. The resulting cross-linked films did not present cytotoxic effect for fibroblasts. Furthermore, the ink could be formulated to be inkjet-printed to create conductive tracks with sinusoidal wave patterns and good uniformity on a degradable poly(L-lactide-co-glycolide) (PLGA) film. PEDOT-based micropatterns embedded in PLGA could withstand flexion and torsion without breaking the conductivity, and could maintain conductivity properties until degradation of the device (at ∼45 days).