A Microfluidic-based Tactile Sensor for Palpating Mice Tumor Tissues

摘要

In light of the need of tissue palpation for Robotics-assisted Minimally Invasive Surgery (RMIS), this paper presents a microfluidic-based tactile sensor for palpating mice tissues for tumor localization. The core of the sensor is a 3x3 sensing-plate/transducer array built into a single polydimethylsiloxane (PDMS) microstructure, with a transducer spacing of 3.75mmx1.5mm. Mounted on a robot, the sensor is pressed against a tissue region with a pre-defined indentation depth pattern, and consequently the stiffness distribution across the tissue region translates to the deflection distribution of the sensing-plate array and is captured by the transducer array underneath as resistance changes. Thus, the recorded data on a tissue region is the sensor deflection as a function of the indentation depth. While the continuous manner of the sensor interacting with a tissue region alleviates the error resulting from non-ideal normal contact between the sensor and the tissue region, the error related to uncertainty in contact point is removed by interpreting the palpation results in terms of the slope of the sensor deflection versus the indentation depth. Two mice tumor tissues are palpated using the sensor. After their noise being removed, the raw data on the two tissues are processed to obtain their slope distribution, the slope error and the percentage error in the slope. The slope distribution of each tissue clearly illustrates the location of a tumor. The palpation results also indicate that this sensor can be integrated into a robotic-assisted system for tumor localization.