Hydrogel Heart Model with Temperature Memory Properties for Surgical Simulation

The continual development of surgical technology has led to a demand for surgical simulators for evaluating and improving the surgical technique of surgeons. To meet these needs, simulators must incorporate a sensing function into the organ model for evaluating the surgical techniques. However, it is difficult to incorporate a temperature sensor into the conventional cardiac training model. In this study, we propose a heart model for surgical training of cardiac catheter ablation made from hydrogel, which has temperature memory properties. The heart model consists of a photo-crosslinkable hydrogel mixed with an irreversible temperature indicator that exhibits a color change from magenta to colorless at 55 °C. The Young's modulus, electrical resistivity, thermal conductivity, and specific heat capacity of the hydrogel material were evaluated and compared with those of human heart. Furthermore, temperature calibration based on the color of the hydrogel material confirmed that the temperature measurement accuracy of the material is ± 0.18 °C (at 56 °C). A heart model for catheter ablation was fabricated using the hydrogel material and a molding method, and the color change due to temperature change was evaluated.