Influencing factors in atomic force microscopy based mechanical characterization of biological cells

AFM-based single cell force spectroscopy is increasingly being used to understand many biological health problems like malaria, cancer etc. A reliable diagnostics needs, accurate measurement and a clear understanding of the influencing factors, which may otherwise sour the measured biomechanics. Results from any successful experimentation should be repeatable and error free. For this, a deeper understanding of the sources of uncertainties, which may affect the results is necessary. In order to assure the accuracy of evaluated properties and to avoid misinterpretation of the experimental data, we have categorized the common causes of uncertainties in an AFM force spectroscopy, based on their sources of origin and discussed possible remedies to them. The present work discusses the assumptions involved in AFM-based biomechanical studies (assumptions in contact model, data analysis, instrument calibration etc.) and their implications in overall estimations of mechanical biomarkers like stiffness, and adhesive strength. Advantages and disadvantages of simultaneous measurement of stiffness and adhe-siveness from single force-indentation data have also been discussed.