Optoacoustic Neuromodulator by In Situ Photothermal Curing of Polydimethylsiloxane

ABSTRACT Precise neural modulation is an important tool in neuroscience research for intervening in specific neural pathways. Photoacoustic is an emerging photonics technology enabling high precision non‐genetic neural stimulation in vitro and in vivo. Fiber‐based and film‐based optoacoustic emitters have demonstrated their capability in fundamental studies of how neurons respond to mechanical stimuli at the single‐cell level, as well as in brain stimulation in vivo. Here, we report a new and general method to fabricate optoacoustic emitters through an in situ photothermal curing process of PDMS (Polydimethylsiloxane) on different platforms, including the tip of tapered fibers with high precision, and flat substrates with programmed patterns. Candle soot‐based tapered fiber optoacoustic emitter (CS‐TFOE) prepared through this new method generated a highly localized ultrasound field and enabled efficient and precise neuromodulation. We designed an integrated and compact photoacoustic neuromodulation system incorporating the FOE, a nanosecond pulsed laser for photoacoustic generation, and a function generator for synchronization. We have shown that the system can be easily integrated with standard neuroscience recording methods, such as Ca 2+ imaging, and achieves effective neuromodulation in vitro.