Fabrication of Reusable and Flexible Artificial Skin with Self-Healing Properties: For Medical Simulator Applications

One promising application of polyurethane is artificial skin for medical training simulators, such as those used for suturing and injection practice. However, many medical simulators are disposable because they cannot self-repair wounds or needle holes. Incorporating self-healing capability into artificial skin would enable repeated use. In this study, two types of self-healing polyurethanes were synthesized to self-heal at room temperature via a hydrogen-bonding mechanism using isophorone diisocyanate (IPDI): IP-PU-1, which is covalently cross-linked, and IP-PU-2, in which part of the triol in the soft segment was replaced with a diol. ATR-FT-IR measurements and evaluations of mechanical and self-healing properties showed that IP-PU-1 exhibited better self-healing performance and a greater abundance of hydrogen bonded carbonyl groups (C=O) than IP-PU-2. Subsequently, injection type simulators (hereafter “injection models”) were developed using both polyurethane based artificial skins, and leak tests were performed to evaluate healing performance. The pressure resistance of punctured and healed samples exceeded typical human blood pressure, indicating adequate reusability. Considering reusability, IP-PU-1 demonstrated better performance than IP-PU-2. Although IPDI based polyurethanes are known to exhibit excellent self-healing properties, their application to medical simulators has not yet been explored. By evaluating reusability from the perspective of molecular structure and incorporating self-healing functionality into the polymer design, this study demonstrates the feasibility of reusable medical simulators. This approach enables a new class of reusable training simulators and may further extend to broader softmaterial applications, including robotic skin.