A minimally invasive and disposable fiber-optic sensor for in-vivo assessment of deep-tissue biomechanical properties

Tissue biomechanical properties are critical biomarkers for the diagnosis of myofascial dysfunction. While elastography is a widely accepted method for measuring these properties and mapping their spatial distribution, its spatial-resolution-imaging-depth tradeoff hindering its ability to retrieve confined deep tissue properties. Conversely, fiber-optic methods demonstrate potential in diagnosing deep tissue pathology due to their confined measurement capabilities and minimal invasiveness. We present a novel fiber-optic sensor designed for in vivo measurement of deep tissue biomechanical properties. This sensor incorporates a Fabry-Pérot interferometer to measure surrounding pressure, enabling the derivation of tissue biomechanical information such as stiffness and viscosity. The sensor's response was characterized on silicone phantoms with different stiffness. Indentation test in hind-leg muscle of rats through a needle shows distinct stiffness readouts in both relaxed and stretched states. The sensor is designed to be disposable and autoclavable, facilitating clinical translation, and we propose a strategy for mass production. Ongoing clinical trials are assessing the sensor's capability to distinguish between normal and diseased tissues and its potential for therapeutic applications via medical injections.