The study on mechanical response of human histiocytic lymphoma cells using an atomic force microscope

Abstract

This work measures force curves of human histiocytic lymphoma cells under a liquid phase using the atomic force microscope (AFM). The experiment uses thirty of the same type and different size cells throughout the experiment. This study analyzes force curves of the cells and calculates the Young's modulus by analyzing the recorded force curves with the help of the Hertz model. The experiment also destroys the cells under continuously applied loading force using an AFM tip. Results show a flat force curve following point of contact for both intact cell and apoptosis cell (entirely destroyed). The force curve of the apoptosis cell becomes steeper than that of the intact cell with increasing loading forces. The calculated Young's modulus of the intact cell nucleus is dependent on the applied loading force of the AFM tip. The Young's modulus of the apoptosis cell also increases over one order of magnitude from that of the intact cell. The average force curve slope for an intact cell in the present experimental data of thirty cells is ‐7.4 ± 1.8 nN/μm, ‐20.0 ± 4.7 nN/μm for the dying cell, and ‐349.5 ± 25.8 nN/μm for the apoptosis cell.