Micropore-array Confining Assisted Young's Modulus Measurement of Suspended Cells Using Atomic Force Microscopy

Mechanical properties of cells (e.g. Young's modulus) reflect cells physiology or pathology, thus making them indexes to evaluate the state of cells. Atomic force microscopy (AFM) is a widely applied platform to characterize cell Young's modulus. Commonly, AFM measurements were performed on adherent cells, for suspended cells are prone to slide during the measurements. However, for the similarity to in vivo state and preclusion of `bottom-effect' artefact, to measure on suspended cells is important. Here we propose a new strategy to perform AFM characterizations on suspended cells. Assisted by a micropore array, we confined suspended cells to immobilize them, facilitating the force-displacement recording to extract accurate values of Young's modulus. The measured Young's modulus of Huh7 cells by the proposed method (1.34 kPa) was consistent with that obtained by the previously reported semi-trypsinization method (1.58 kPa). Furthermore, this new design is capable of measuring mechanical properties of rare cells from large-volume samples in liquid biopsy for practical clinical applications.