Wound closure using sutures, staplers, and clips are the main medical procedures used after surgical operations. Bioadhesive materials have been additionally used to stop breeding and air leakage at closed wound, however, existing bioadhesive materials have a problem in achieving both strength and biocompatibility. Therefore, we used hydrophobically-modified Alaska pollock gelatin, which is obtained by introducing various hydrophobic groups into gelatin derived from Alaska pollack, which has low-temperature fluidity. The adhesive had excellent burst strength against blood vessels and lung tissue. In addition, it was found that the cured adhesive on the tissue after exhibits an anti-adhesion effect. Also, resulting adhesive materials degraded in rat subcutaneous tissue and showed high biocompatibility. While, tissue-adhesive particles designed for application to early gastrointestinal cancer-removed sites showed excellent coating and perforation closing effects on duodenal tissue. Moreover, the tissue adhesive sheets prepared by the electrospinning method can effectively close the lung tissue just only by pasting. Since these bioadhesive materials are enzymatically degraded in the body without causing a strong inflammatory response, they are expected to be useful as medical materials for tissue adhesion and closure after surgical operations and medical procedures.

A method for estimating the thickness and Young’s modulus of the adhesive layer in an adhesively bonded sandwich beam from the sound caused by an impact was investigated. A method obtained by Mead et al. was applied to the vibration of an adhesive sandwich beam to obtain its eigenfrequencies, and the thickness and modulus of elasticity of the adhesive layer were probabilistically selected to generate many teaching data. A system for inverse estimation of the thickness and Young’s modulus of the adhesive layer from the eigenfrequencies was constructed by machine learning from the teaching data. By inputting the experimental results into this inverse estimation system, the adhesive thickness of the specimens was precisely predicted, but the estimation of Young’s modulus was not precise.

We discuss the multi-scale dynamics of pressure-sensitive adhesives during debonding. We first show our experimental results on double-sided adhesive tapes as an example, and then introduce our theoretical or numerical models to explain the observed behavior. Through this paper, we will stress that the connection between different scales is important for describing complex mechanical behavior in pressure-sensitive adhesives.