Bioinspired fiber-optic acoustic flow sensor for high-fidelity heart sounds sensing

Heart sound sensors are essential tools for the early detection of cardiovascular and respiratory diseases. The core component of these sensors is the acoustic transducer, whose performance in capturing heart sound signals critically influences the accuracy of subsequent analysis and diagnosis. However, conventional acoustic transducers typically employ rigid diaphragms with poor mechanical compliance, limiting their ability to effectively couple with low-frequency, low-intensity heart sound signals. In nature, the spider can capture acoustically induced air particle motion using a slender orb-web across a broad frequency range at maximal physical coupling efficiency. Herein, inspired by this mechanism, we present a fiber-optic microphone based on a bioinspired spider-web-like structure (BSS) for heart sound detection. The BSS, with its high mechanical compliance, closely depicts the motion of acoustic particles and employs Fabry-Perot interference to convert its mechanical vibrations into optical signals, minimizing interference during signal readout. This sensor achieves ultra-high sensitivity (6714.29 nm·Pa−1 at 100 Hz), exceptional low-frequency response down to 1 Hz, and inherent directionality to sound, proving its suitability for the rapid detection of weak, low-frequency heart sound signals. This bioinspired sensing approach provides a novel and effective strategy for high-fidelity detection of weak, low-frequency acoustic signals.