In situ acoustic manufacturing of conformal brain–computer interfaces

Abstract Brain–computer interfaces are usually prefabricated and surgically implanted, creating mechanical mismatch, tissue manipulation, inflammation, and signal instability. We report AI-guided in situ ultrasound printing (AiUP), a closed-loop acoustic manufacturing strategy that prints conformal cortical electrodes directly on the dura or brain surface. AiUP integrates pressure-programmable fluorinated silk fibroin nanocages, modular conductive ultrasound-printable inks, ultrasound imaging–guided focused-ultrasound hardware, and an AI controller, EchoAgent. Nanocages collapsed at defined acoustic pressures to release crosslinkers and trigger localized, nonthermal hydrogel formation, whereas EchoAgent planned trajectories, compensated acoustic distortion, and corrected path drift. AiUP produced conductive hydrogel electrodes with ~200 μm resolution, 30 s gelation, ~20 kΩ impedance, 3-month recording stability, and enabled rodent seizure warning and pig neural decoding.