Abstract：
Photoacoustic (PA) emitters are emerging ultrasound sources offering high spatial resolution and ease of miniaturization. Thus far, PA emitters rely on electronic transitions of absorbers embedded in an expansion matrix such as polydimethylsiloxane (PDMS). Here, it is shown that mid-infrared vibrational excitation of C─H bonds in a transparent PDMS film can lead to efficient mid-infrared photoacoustic conversion (MIPA). MIPA shows 37.5 times more efficient than the commonly used PA emitters based on carbon nanotubes embedded in PDMS. Successful neural stimulation through MIPA both in a wide field with a size up to a 100 µm radius and in single-cell precision is achieved. Owing to the low heat conductivity of PDMS, less than a 0.5 °C temperature increase is found on the surface of a PDMS film during successful neural stimulation, suggesting a non-thermal mechanism. MIPA emitters allow repetitive wide-field neural stimulation, opening up opportunities for high-throughput screening of mechano-sensitive ion channels and regulators.
摘要：
光声(PA)发射器是新兴的超声源,其提供高空间分辨率和易于小型化。到目前为止,PA发射体依赖于嵌入在膨胀基质如聚二甲基硅氧烷(PDMS)中的吸收体的电子跃迁。这里,结果表明，透明PDMS薄膜中C─H键的中红外振动激发可以导致有效的中红外光声转换（MIPA）。MIPA显示比基于嵌入在PDMS中的碳纳米管的常用PA发射体更有效37.5倍。通过MIPA成功的神经刺激在一个大的领域与一个100微米的半径和单细胞精度。由于PDMS的低导热性，在成功的神经刺激过程中，PDMS膜表面的温度升高小于0.5°C，暗示了一种非热机制。MIPA发射器允许重复的宽视野神经刺激，为机械敏感性离子通道和调节器的高通量筛选开辟了机会。
