Sensors have been developed to determine the concentration of specific compounds in situ. They are already widely employed as a practical technological tool in the clinical and healthcare fields. Recently, another concept of biosensing has been receiving attention: biosensing for the evaluation of molecular potency. The author described the idea as qualified analysis. The development of this novel concept has been supported by the development of related technologies, such as electrochemistry, molecular interface science, molecular design, molecular biology (genetic engineering), and cellular/tissual engineering. This study addresses this new concept of biosensing and its application to the evaluation of the potency of chemicals in biological systems, in the field of cellular/tissual engineering. Cellular biosensing will provide valuable information for both pharmaceutical research and chemical safety, and be applicable in drug discovery in vitro as a screening tool.