In-situ characterization of the uncrimping process of arterial collagen fibers using two-photon confocal microscopy and digital image correlation

• Type of Material: Article
• Authors: Luke Brewster, Emory University; R Wang, George W Woodruff Sch Mech Engn; RL Gleason, George W Woodruff Sch Mech Engn
• Language: English
• Date: 2013-10-18
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2013 Elsevier Ltd.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.jbiomech.2013.08.001
• Title of Journal or Parent Work: Journal of Biomechanics
• ISSN: 0021-9290
• Volume: 46
• Issue: 15
• Start Page: 2726
• End Page: 2729
• Keywords: Engineering, Biomedical; Life Sciences & Biomedicine; Technology; Digital image correlation; DEVICE; Science & Technology; Engineering; Two-photon excitation microscopy; CAROTID ARTERIES; WALL MECHANICS; Deformation; Adventitia; Arterial mechanics; Biophysics
• Research Categories: Engineering, Biomedical; Biophysics, Medical

Abstract

Uncrimping of collagen fibers in the arterial wall is an integral process in regulating the macro-level mechanical response of arteries. Uncrimping of collagen fibers leads to a gradual, but significant strain-stiffening response of the artery at physiological pressures and prevents overdistention at elevated pressures. In this study, we imaged adventitial collagen fibers from fresh primate arteries using two-photon excitation microscopy while subjecting the arteries to physiological inflation pressures and axial stretches. The imaging focal plane was fixed at a constant radial location in the adventitial wall by adjusting the focal distance as the arteries inflated, allowing for the continuously monitoring of the uncrimping process of a single region of collagen fibers. Digital image correlation was then applied to the sequential images to assess and correlate the local displacements to manual traces of selected reference fibers and their engagements. We found that the collagen fibers of interest became fully engaged at a luminal pressure of 20. mmHg, this was then followed by rotation of these fibers as the bulk artery continued to dilate. This technique helps to further the understanding of the uncrimping process of collagen fibers under physiological loads, which can aid in the development of more accurate microstructural constitutive models.