Cell hardness measurement by using two-fingered microhand with micro force sensor

In the field of bioscience, such as regeneration medicine and cloning, the manipulation and analysis for cells are performed by many researchers. However, manual operation for such micro objects is not feasible and practical for beginner operators. As for the problem, we have developed a two-fingered microhand supporting manual operation. Using the microhand, we can manipulate cells i.e., grab, rotate, carry, and so on - like when using chop sticks. The stiffness measurement of a cell is a key approach in single cell analysis techniques. It is important in indicating cell condition, because the stiffness of a cancer cell is lower than that of a normal cell as an example. However, measuring stiffness is very difficult, because deformations of cell are plasticly, and many researches to measure the stiffness of cell don´t deal with plastic deformation. So, in this paper, the cell hardness is calculated instead of cell stiffness by measuring the reaction force caused in the process of cell deformation via a micro force sensor attached to the end-effector of the microhand. Our results point out that this can be one efficient measurement method for acquiring cell hardness. In this paper, three topics are discussed. First one is the fabrication of the end-effector with micro force sensor. Second one is the method of measuring hardness of cell. As a last one, the hardness of the fibroblastic cell is measured by proposed method and the effectiveness of the proposal technique is shown.