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

Abstract 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.