Fiber-optic photoacoustic enables targeted neuromodulation and stress reduction in mice

Ultrasound neuromodulation offers a non-invasive approach to modulate neural activity in the central nervous system. Precise, minimally invasive devices capable of targeted stimulation remain limited. A 200 µm diame- ter fiber-optic photoacoustic emitter (FPE) was developed, coated with a MXene (Ti 3C2Tx) and polydimethylsiloxane composite to generate controllable, broadband ultrasonic waves with high spatial precision. Using this FPE to stimu- late the medial prefrontal cortex in mice, it was observed marked alleviation of acute social defeat stress -induced emotional stress, evidenced by reduced anxiety-like behavior and increased social interaction. This approach enables near-field, broadband, and tunable ultrasound neuromodulation with potential applications in treating neuropsychi- atric disorders involving emotional regulation.