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Title: Nanomechanical investigation of soft biological cell adhesion using atomic force microscopy
Author: Siamantouras, Eleftherios
ISNI:       0000 0004 5356 0351
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2014
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Cell-to-cell adhesion is critically important for the improved secretory function of endocrine pancreatic beta (β)-cells and for the progression of fibrosis in the renal proximal tubule in Diabetic Nephropathy. In this research project the effects of specific biochemical treatment on functional cell-to-cell adhesion and single cell mechanics were systematically investigated. Atomic Force Microscopy (AFM) Single Cell Force Spectroscopy was applied to quantitatively characterise E-cadherin mediated surface ligation and cytoskeletal reorganisation in the pancreatic mouse insulinoma MIN6 and human kidney proximal tubule HK2 cell model. AFM tipless cantilevers were functionalised with a single cell or a spherical microbead for performing cell-to-cell adhesion and single cell indentation experiments respectively. The impact of elastic deformation of single cells into cell-to-cell adhesion was examined by per-forming adhesion experiments at various retraction speeds. The results illustrate that both adhesive and mechanical properties of single cells constitute important underlying factors of the physiological and pathological conditions under investigation since they were significantly affected by biochemical changes. More specifically, it is suggested that the enhanced secretory function of MIN6 cells upon calcium-sensing re-ceptor activation is owned to a combination of increased E-cadherin mediated cell-to-cell adhesion and decreased elastic (E)-modulus of single cells. In addition, it was shown that treatment of HK2 with the cytokine TGF-β1 decreased E-cadherin mediated cell-to-cell adhesion and increased E modulus of single cells, suggesting a mechanism that initiates early fibrotic changes in the tubular epithelia. Overall, both studies demonstrate that alterations of biological states evoke complex interactions between E-cadherin and actin cytoskeleton as manifested by the interplay between the mechanistic behaviour and surface binding of the cells. Therefore single cell mechanics have profound effects on cell-to-cell adhesion characterisation, particularly when physiological versus pathological states are to be investigated.
Supervisor: Not available Sponsor: School of Engineering ; University of Warwick
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QH301 Biology