Combining nano-physical and computational investigations to understand the nature of “aging” in dermal collagen

Abstract

Tarek Ahmed,1 Anthony Nash,2 Kristina EN Clark,3 Marion Ghibaudo,4 Nora H de Leeuw,2 Anne Potter,4 Richard Stratton,3 Helen L Birch,5 Ramona Enea Casse,4 Laurent Bozec1 1Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, 2Department of Chemistry, University College London, 3Centre for Rheumatology and Connective Tissue Diseases, Division of Medicine, University College London, London, UK; 4L’Oréal Research and Innovation, Aulnay-sous-Bois, France; 5Division of Surgery and Interventional Science, UCL Institute of Orthopaedics and Musculoskeletal Science, University College London, London, UK Abstract: The extracellular matrix of the dermis is a complex, dynamic system with the various dermal components undergoing individual physiologic changes as we age. Age-related changes in the physical properties of collagen were investigated in particular by measuring the effect of aging, most likely due to the accumulation of advanced glycation end product (AGE) cross-links, on the nanomechanical properties of the collagen fibril using atomic force microscope nano-indentation. An age-related decrease in the Young’s modulus of the transverse fibril was observed (from 8.11 to 4.19 GPa in young to old volunteers, respectively, P<0.001). It is proposed that this is due to a change in the fibril density caused by age-related differences in water retention within the fibrils. The new collagen–water interaction mechanism was verified by electronic structure calculations, showing it to be energetically feasible. Keywords: collagen, aging, atomic force microscopy, nanomechanics, advanced glycation end products, nanotechnology

Keywords

• Collagen
• Ageing
• Atomic Force Microscopy
• Nanomechanics
• Advanced Glycation End Products
• Nanotechnology