Enhanced laser-induced PEDOT-based hydrogels for highly conductive bioelectronics

Conductive hydrogels-particularly poly(3,4-ethylenedioxythiophene) (PEDOT)-based hydrogels-possess mechanical properties comparable to biological tissues and superior biocompatibility. Laser treatment affords a promising approach for the development of well-patterned PEDOT bioelectrodes. However, the weak photothermal conversion of pristine PEDOT-based solution results in very limited phase separation and thus low conductivity. Here, we report an enhanced laser-induced PEDOT (ELIP)-based hydrogel via a metastable liquid-liquid contact (MLLC) strategy. Such MLLC pretreatment renders the extension of PEDOT chains with an increase in the conjugation length, which greatly improves the light absorbance and photothermal conversion capability, achieving a conductivity of ≤955 S/cm and ∼3 μm-precision patterning. The laser treatment with an intensive and instantaneous thermal effect also elevates the interfacial adhesion and electrochemical stability of the proposed ELIP in physiological environments. Serving as the stimulator and signal recording for bioelectronic devices, the patterned ELIP showcases potential in nerve-conduction blocks for pain treatments.