PEDOT:PSS hydrogels are widely studied for neural interfaces due to their mixed electronic-ionic conductivity and tissue-mimetic mechanical properties. However, the limited photothermal conversion of pristine PEDOT:PSS restricts effective laser-induced phase separation, resulting in low conductivity. To address this, the Kaichen Xu research group from Zhejiang University proposed a metastable liquid-liquid contact (MLLC) pretreatment, which extends the conjugation length of PEDOT chains and increases light absorption in the visible spectrum.
Upon continuous-wave 532 nm laser irradiation, the MLLC-treated films undergo efficient localized heating and phase separation, generating interconnected PEDOT-rich domains. The resulting material, termed enhanced laser-induced PEDOT (ELIP), exhibits a maximum conductivity of 955 S/cm and a patterning resolution of 3 μm. Compared to untreated controls, the conductivity is increased by over twofold, and interfacial adhesion to flexible substrates is significantly improved.
For functional validation, ELIP was fabricated into flexible cuff electrodes and applied to the sciatic nerve of rats. When subjected to kilohertz-frequency alternating current, the electrodes achieved reversible nerve-conduction block, effectively blocking the nerve signals that control movement. This demonstrated the potential of ELIP for neuromodulation applications such as pain therapy.
“The ELIP hydrogel integrates high conductivity, submicron resolution, mechanical compliance, and long-term stability, meeting essential requirements for next-generation bioelectronic platforms.” said Dr. Kaichen Xu, the study’s corresponding author.
National Science Review