Sensing inhomogeneous mechanical properties of human corneal Descemet's membrane with AFM nano-indentation. (October 2017)

• Record Type: Journal Article
• Authors: Di Mundo, Rosa; Recchia, Giuseppina; Parekh, Mohit; Ruzza, Alessandro; Ferrari, Stefano; Carbone, Giuseppe
• Is Part Of: Journal of the mechanical behavior of biomedical materials. Volume 74(2017)
• Page Start: 21
• Page End: 27
• Publication Date: 2017-10
• Subjects: Atomic Force Microscopy (AFM) -- Nano-indentation -- Elastic modulus -- Adhesion -- Descemet's membrane -- Cornea -- Tetrahedral hard punch; Biomedical materials -- Periodicals; Biomedical materials -- Mechanical properties -- Periodicals; Biomedical materials; Biomedical materials -- Mechanical properties; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.jmbbm.2017.05.019
• Languages: English
• ISSNs: 1751-6161

Abstract

Abstract: The paper describes a highly space-resolved characterization of the surface mechanical properties of the posterior human corneal layer (Descemet's membrane). This has been accomplished with Atomic Force Microscopy (AFM) nano-indentation by using a probe with a sharp tip geometry. Results indicate that the contact with this biological tissue in liquid occurs with no (or very low) adhesion. More importantly, under the same operating conditions, a broad distribution of penetration depth can be measured on different x-y positions of the tissue surface, indicating a high inhomogeneity of surface stiffness, not yet clearly reported in the literature. An important contribution to such inhomogeneity should be ascribed to the discontinuous nature of the collagen/proteoglycans fibers matrix tissue, as can be imaged by AFM when the tissue is semi-dry. Using classical contact mechanics calculations adapted to the specific geometry of the tetrahedral tip it has been found that the elastic modulus E of the material in the very proximity of the surface ranges from 0.23 to 2.6 kPa.