The performance of implantable bioelectrodes is frequently compromised owing to inflammatory tissue reactions. Korean researchers at Gwangju Institute of Science and Technology (GIST) report tthe novel bioelectrodes which can effectively modulate macrophage polarization with fine-controlled surface roughness. The study is accepted in the journal ACS Nano in April.

Macrophage responses (pro-inflammatory or pro-repair) to foreign materials are critical in the in vivo performances of implants. Work by the researchers, led by Prof. Jae Young Lee, demonstrated that polypyrrole/heparin bioelectrode with optimal roughness can mitigate pro-inflammatory response of macrophages and excessive scar tissue formation.

The researchers fabricated heparin-doped polypyrrole (PPy/Hep) electrodes of different surface roughness by varying the charge densities during electrochemical synthesis. Among them, the PPy/Hep with optimal roughness (14.5 nm) was found to successfully inhibit inflammatory polarization of macrophages and substantially decreased scar tissue formation. Consequently, ECG in a rat could be monitored without a significant loss of signal sensitivity up to for 10 days, while conventional gold electrodes and PPy/Hep displaying non-optimal surface structures lose their sensitivity after implantation.

Prof. Lee said that “Our results can provide insights into the understanding of the interaction between conductive materials and the innate immune system, and clues to produce various immuno-compatible implantable biomedical materials for various applications.”

PPy/Hep bioelectrode with the optimal topography reduces inflammatory macrophage and tissue reactions and enables stable long-term signal recording

[Reference] Lee et al., (2022) “High-performance implantable bioelectrodes with immunocompatible topography for modulation of macrophage responses”, ACS Nano

[Main Author] Sanghun Lee (GIST), Junggeon Park (GIST), Semin Kim (GIST), Jehyung Ok (SKKU), Jung Il Yoo (GIST), Yong Sook Kim (CNU), Youngkeun Ahn (CNU), Tae-il Kim (SKKU), Heung Cho Ko (GIST), and Jae Young Lee (GIST)

* Contact : jaeyounglee@gist.ac.kr