A Soft Resistive Sensor with a Semicircular Cross-Sectional Channel for Soft Cardiac Catheter Ablation

Abstract

The field of soft robotics has attracted the interest of the medical community due to the ability of soft elastic materials to traverse the abnormal environment of the human body. However, sensing in soft robotics has been challenging due to the sensitivity of soft sensors to various loading conditions and the nonlinear signal responses that can arise under extreme loads. Ideally, soft sensors should provide a linear response under a specific loading condition and provide a different response for other loading directions. With these specifications in mind, our team created a soft elastomeric sensor designed to provide force feedback during cardiac catheter ablation surgery. Analytical and computational methods were explored to define a relationship between resistance and applied force for a semicircular, liquid metal filled channel in the soft elastomeric sensor. Pouillet’s Law is utilized to calculate the resistance based on the change in cross-sectional area resulting from various applied pressures. FEA simulations were created to simulate the deformation of the sensor under various loads. To confirm the validity of these simulations, the elastomer was modeled as a neo-Hookean material and the liquid metal was modeled as an incompressible fluid with negligible shear modulus under uniaxial compression. Results show a linearly proportional relationship between the resistance of the sensor and the application of a uniaxial force. Altering the direction of applied force results in a quadratic relationship between total resistance and the magnitude of force.

Advancement of Flexible Robot Technologies for Endoluminal Surgeries

“…Several surgical instruments with a force-sensing capability have been developed based on the abovementioned sensor-based approaches [88]- [90]. The sensor types can be categorized as electrical [91]- [93] and optical [94]- [96].…”

Interface-Controlled Phase Separation of Liquid Metal-Based Eutectic Ternary Alloys

“…Low-meting-point post-transition metal-based liquid alloys, also known as liquid metals (LMs), are a burgeoning subject of studies due to their unique interfacial characteristics. − The interfaces of LMs are atomically smooth, chemically active, and stimulus-responsive, enabling a range of applications from materials synthesis and thermal management − to catalysis − and sensing. − LMs are highly fusible alloys that can dissolve various metals. ,, The stratified surface of LMs in such alloys can undergo phase separation by oxidation and simultaneous templating onto the surface of the LM. Subsequently, the oxide at the interface can be harvested in a procedure that is generally referred to as “LM-assisted interfacial synthesis of two-dimensional oxides”. − Additionally, by inducing physical perturbation at the LM interfaces, phase separation of solute metals, in their zero-valent form, can be achieved.…”