Evaluation of local and internal elasticity of hydrogel materials by using light-driven gel actuator

We propose a method for evaluating local and internal elasticity of hydrogel materials. In this method, we deform inside of a sample by using a light-driven gel actuator and evaluate internal elasticity from strain of the material. Since the actuator can be driven by irradiating light through a microscope without wiring, this method enables us to evaluate local and internal elasticity which is difficult to be measured with conventional methods. In this study, we compared strains of two samples with different elasticities. It was observed that strain of a softer sample was larger than that of a harder sample. Furthermore, we can estimate the harder sample is approximately 1.3 times harder than the softer sample. Therefore, we succeeded in evaluating local and internal elasticities of samples with the proposed method.