Topographical Patterning of Cell‐Repellent Interfaces for Immune‐Stealth Implantable Electronics via Multiphoton Ablation Lithography

Stable and reliable operation of implantable electronics must ensure both high-quality electrical performance and chronic biocompatibility. Here, immune-stealth implantable electronics fabricated by multiphoton ablation lithography are introduced. The cell-repellent interface, consisting of micro-grooves and nano-islands, can be created by laser-assisted topography patterning on a thin film substrate. This patterned surface demonstrates a 20-fold increase in cell-repellent effectiveness against immune cells such as macrophages and fibroblasts due to disturbance of focal adhesion. Furthermore, the cell-repellent interface can also be patterned on the sub-micron electrode layer without compromising its electrical and electrochemical performance. When the electrocardiogram (ECG) sensor applying the cell-repellent interface is implanted into a rat subcutaneous tissue, inflammation and fibrotic reactions are effectively suppressed for 6 weeks. Consequently, stable ECG readings with clear PQRST waveforms are obtained in real-time for 4 weeks, suggesting its potential to enhance chronic biocompatibility of implantable electronics.