PDMS ring-spring soft probe for nano-force biosensing

We present an innovative design for a flexible probe to study mechanisms of biological force sensing and force generation in the piconewton to micronewton range. Made of polydimethylsiloxane (PDMS) and employing a novel ring-spring section with adjustable size, the device works both as a force sensor and force actuator by precise calibration of its tunable stiffness and optical measurement of ring deformation. In addition, the tip geometry of the probe can be properly shaped to fit the anatomical profile of the sensory receptor of interest and to reproduce the in vivo stimulation. Finally, use of Finite Element Method (FEM) modal analysis confirms that the resonance frequencies of probes are outside the frequency range of interest for many sensory systems.