Mapping of biomechanical properties of cell lines on altered matrix stiffness using atomic force microscopy

Abstract

Understanding nanomechanical properties such as elastic modulus, cell adhesion force and stiffness of healthy-, cancerous- and drug-treated cancer cells under varying matrix microenvironment have great roles in cellular processes like morphogenesis, mechanotransduction, focal adhesion, motility, metastasis and drug delivery. AFM is an important technique to depict nanomechanical properties and mechanoadaptation response of cell lines in different microenvironment. In the present study, two different cell categories, i.e. healthy and cancerous, having two different types in each category, i.e. 3T3 fibroblast, HaCaT keratinocyte, untreated and drug-treated MCF-7 and MDA-MB 231 were chosen for cell culture on PDMS matrix of different stiffness without any prior protein layer to facilitate unbiased cell growth. Subsequently cell mechanics response was evaluated by AFM technique and correlated with immunofluorescence assay. Furthermore, cell culture was performed to stiffer matrix after initial incubation on soft matrix and analysed the cell mechanics using AFM and fluorescence assay to understand cell adaptation with matrix stiffness. Results demonstrate deviations in elastic modulus, stiffness and adhesion force induced by matrix stiffness in all four cell lines. Study revealed the doxorubicin drug can significantly influence the cell mechanics and disease state of cancer cells. Variation of cytoskeleton structure, actin fibre and focal adhesion primarily accounts for cell mechanics response in terms of elastic modulus, stiffness and adhesion of cell under varying matrix stiffness. Experimental evidence demonstrates that a greater understanding of the mechanics in terms of cellular deformability and its interactions with extracellular environments offer enormous potential for new advances in disease diagnostics, therapeutics and influence of drug treatment in several complex processes.