A Piezoelectric Microtool for In Vitro Elastic Modulus Measurement and Hepatocellular Carcinoma Boundary Identification

Abstract

Accurate identification of tumor boundaries is crucial for effective local treatment and protection of surrounding healthy tissue. However, current methods for rapidly characterizing local tissue biomechanical properties remain limited. In this study, we present a novel MEMS-integrated piezoelectric sensor-based medical microtool (IPS-MMT), this device can map the elastic modulus of local tissues in real time and at the sub-millimeter scale, enabling rapid and localized measurements under controlled in vitro conditions. Our device features the integration of a 100 µm‑thick piezoelectric sensor onto a 300 µm‑diameter tungsten tip fabricated via a scalable electrochemical etching platform. This configuration transduces minute tissue deformations into quantifiable electrical signals with a spatial resolution of ∼15 µm and a response time under 10 ms. In ex vivo studies on rat organs and human hepatocellular carcinoma specimens, the IPS-MMT resolved distinct tissue-stiffness differences among normal, peritumoral, and cancerous regions. Independent rheological measurements on six rat organ tissues showed a mean relative agreement of 91.83% with the IPS-MMT measurements, supporting tissue elastic modulus as a promising biomechanical biomarker for tissue differentiation and highlighting the potential of biomechanics-guided precision ablation.