Development of Adhesion Force microscopy for the surface charge analysis of collagen fibrils in vivo and in vitro

Abstract

Collagen fibrils are a key component of the extracellular matrix. In this study, we use the adhesion force between a silicon probe and a collagen substrate to demonstrate the sensitivity of adhesion force towards charge distribution on the surface of collagen fibrils. We map the charge distribution at the surface of single in vivo and in vitro assembled collagen fibrils and characterize the location and strength of three sub-D-band regions that have been observed previously by cryo-electron microscopy. Our approach provides an adhesion fingerprint unique to each fibril type and points to local charge variations at the sub-D-band level even along a single fibril. We also demonstrate that this technique is capable of detecting changes on the surface of collagen fibrils because of glycation. It opens the road for a detailed analysis of collagen fibrils surface charge modifications due to ligand binding or mechanical strain on a fibril-by-fibril basis.