A Drop-Printing Strategy for Low-Stress, Conformal Bioelectronics

• • Drop-printing achieves positional deviation of less than 20 μm via regulation of three-phase contact lines, enabling high-precision conformal wrapping on uneven surfaces, critical for reliable bioelectronic interfacing. • • The method utilizes capillary pressure generated by interfacial liquid penetrating microstructures, significantly reducing stress concentration during film deformation, preventing fracture of non-stretchable films. • • Demonstrated on a 150 nm-thick patterned Au film, the technique successfully conforms to uneven surfaces, showcasing its applicability to ultrathin, fragile electronic films. • • In vivo validation on a rat brain shows that drop-printed silicon microfilm (SiHF) conformally wraps the brain surface, and NIR laser stimulation triggers forelimb movement with synchronized brain electrophysiological signals, proving functional integrity and potential for neuromodulation.