High-precision neural stimulation by a highly efficient candle soot fiber optoacoustic emitter
Guo Chen, Linli Shi, Lu Lan, Runyu Wang, Yueming Li, Zhiyi Du, Mackenzie Hyman, Ji-Xin Cheng, Chen Yang
Frontiers in Neuroscience 2022 · 10.3389/fnins.2022.1005810
Abstract
Highly precise neuromodulation with a high efficacy poses great importance in neuroscience. Here we developed a candle soot fiber optoacoustic emitter (CSFOE), capable of generating a high pressure of over 10 MPa with a central frequency of 12.8 MHz, enabling highly efficient neuromodulation in vitro . The design of the fiber optoacoustic emitter, including the choice of the material and the thickness of the layered structure, was optimized in both simulations and experiments. The optoacoustic conversion efficiency of the optimized CSFOE was found to be 10 times higher than the other carbon-based fiber optoacoustic emitters. Driven by a single laser, the CSFOE can perform dual-site optoacoustic activation of neurons, confirmed by calcium (Ca 2+ ) imaging. Our work opens potential avenues for more complex and programmed control in neural circuits using a simple design for multisite neuromodulation in vivo .
Abstract via europepmc.
Exposures
Exposure 1: Candle soot fiber optoacoustic emitter on cultured cortical neurons
Target: cultured neurons — “GCaMP6f-labeled primary cortical neuron culture”
Device: custom-built · candle soot fiber optoacoustic emitter (CSFOE) ✓
| Waveform | other patterned | |
|---|---|---|
| Fundamental frequency (kHz) | 12,800 | ✓✓✓ |
| Pulse duration (ms) | not reported | ⚑ |
| Pulse repetition frequency (Hz) | 1,700 | ✓✓✓ |
| Duty cycle (%) | not reported | |
| Sonication duration (s) | 0.003 | ✓✓✓ |
| Free-field pressure (kPa) | 8,800, 12,400swept | ✓✓✓⚑ |
|---|---|---|
| Free-field Isppa (W/cm²) | 388.8 | ✓✓✓⚑ |
| Free-field Ispta (W/cm²) | 0.13 | ✓✓✓ |
| In-situ estimate | not applicable | |
| In-situ pressure (kPa) | not applicable | |
| In-situ Isppa (W/cm²) | not applicable | |
| In-situ Ispta (W/cm²) | not applicable |
Optoacoustic stimulation: 3 ns laser pulses at 1030 nm and 1.7 kHz repetition rate, delivered as a 3 ms train of 5 pulses per stimulation, with pulse energy 46, 56 or 65 uJ. Each laser pulse produces a broadband bipolar acoustic transient centred at 12.8 MHz.
Flags from extraction
exposures[0].free_field.pressure_kpa— Peak-to-peak pressures measured by hydrophone in water for the laser conditions of 56 uJ (8.8 MPa) and 65 uJ (12.4 MPa); the list holds these two conditions, not a range. The text also gives about 8 MPa as the activation threshold and 10 to 15 MPa as device maxima.exposures[0].free_field.isppa_w_cm2— ISPPA and ISPTA were calculated by the authors from the peak-to-peak pressure of 12.4 MPa and the 1.7 kHz repetition rate, not measured; the paper's duty cycle is not stated.exposures[0].timing.waveform— Laser-generated optoacoustic transients rather than a sinusoidal carrier; recorded as other_patterned.exposures[0].timing.pulse_duration_ms— Only the 3 ns laser pulse duration is stated; the acoustic transient duration is not given.n_subjects— Cultures from three batches or dishes are mentioned; neuron counts (N=10 to 30) are per group; no total number of cultures is stated.exposures[0].device.family— Emitter fabricated by the authors; no commercial maker. Scope note: an optoacoustic fiber emitter rather than a piezoelectric transducer.