Micro/nano-manufacturing of bioinspired blood-repellent surfaces for extreme application in surgical electrodes

Abstract Surgical electrodes are frequently associated with disadvantages such as high surface adhesion and severe thermal damage to tissues, which threaten operation quality and patient safety. In this study, by mimicking the micromorphology and bio-anti-adhesion of shark skin, we propose a strategy that utilises nanoscale aluminium oxide (Al2O3) films deposited on bioinspired shark skin (BSS) microstructures to design a composite surface (Al2O3@BSS) and integrate it onto both flat sides of the surgical electrodes. Micro/nano-manufacturing of the Al2O3@BSS surface was sequentially accomplished using nanosecond laser texturing, atomic layer deposition, and low-temperature annealing, endowing it with excellent blood-repellent properties. Visualisation experiments revealed that the tensile stress gradient of the blood coagulum with increasing thickness under a thermal field prompted it to separate from the Al2O3@BSS surface, resulting in anti-adhesion. Furthermore, it was observed for the first time that Al2O3 films can transiently excite discharge along a dielectric surface (DADS) to ablate tissues while suppressing Joule heat, thereby minimising thermal damage. A combination of ex vivo tissue and living mouse experiments demonstrated that the Al2O3@BSS electrodes exhibited optimal comprehensive performance in terms of anti-adhesion, damage minimisation, and drag reduction. In addition, the Al2O3@BSS electrode exhibited remarkable antibacterial efficacy against Escherichia coli and Staphylococcus aureus. The proposed strategy can meet the extreme application requirements of surgical electrodes to improve operation quality and offer valuable insights for future studies.