Neural Stimulation In Vitro and In Vivo by Photoacoustic Nanotransducers

Abstract

Neuromodulation is crucial for the understanding of brain circuits and treatment of neurological diseases. This work demonstrates a new photoacoustic nanoparticlebased neural stimulation technique. Synthesized nanoparticles transduce nearinfrared light to ultrasound locally at the neuronal membrane and evoke neural activation in vitro and in vivo. Through targeting the mechanosensitive ion channel TRPV4, the modified nanotransducers achieve neural activation with enhanced specificity. Together, photoacoustic nanotransducers offer opportunities for nongenetic neuromodulation with deep tissue penetration.

High-precision neural stimulation through optoacoustic emitters

“… 50 Per the thermal confinement, the laser pulse width needs to be shorter than the thermal conduction time aiming at sufficient efficiency. For example, in the study of a nanoparticle-based scenario, 39 the thermal diffusion time constant is , which guided the researchers to use a 3-ns pulsed laser for efficient optoacoustic generation.…”

“…According to Eq. (10), materials with superior light absorption coefficient (e.g., graphite , 36 , 44 , 51 carbon nanotubes (CNT) , 37 , 38 , 52 gold nanoparticles , 53 , 54 and polymer nanoparticles 39 ) and large thermal expansion coefficient [e.g., polydimethylsiloxane (PDMS) , 37 epoxy 36 , 44 ] could be utilized to boost the absorption and expansion, respectively, subsequently producing acoustic waves with a high pressure. 45 …”

“… 80 – 82 Among them, semiconducting polymer nanoparticles represent a new class of nanotransducers due to their unique absorption in the near-infrared (NIR) wavelength, excellent biocompatibility, and programmable biodegradability. 73 Only recently, optoacoustic neuromodulation using nanoparticles has been achieved 39 ( Fig. 5 ).…”

“…Inset: Example absorption agents including graphite, 36 CNT, 37 , 38 and PANs. 39 (b) Optoacoustic stimulation platforms based on optical fibers, biocompatible films, and nanotransducers. (Created with Ref.…”

“…Furthermore, to address the urgent need for noninvasive neuromodulation, semiconducting polymer nanoparticles-based photoacoustic nanotransducers (PANs) were developed by Jiang et al. 39 [ Fig. 1(b) , right].…”