Understanding the viscoelastic behavior of collagen matrices through relaxation time distribution spectrum

Abstract

This study aims to provide understanding of the macroscopic viscoelastic behavior of collagen matrices through studying the relaxation time distribution spectrum obtained from stress relaxation tests. Hydrated collagen gel and dehydrated collagen thin film was exploited as two different hydration levels of collagen matrices. Genipin solution was used to induce crosslinking in collagen matrices. Biaxial stress relaxation tests were performed to characterize the viscoelastic behavior of collagen matrices. The rate of stress relaxation of both hydrated and dehydrated collagen matrices shows a linear initial stress level dependency. Increased crosslinking reduces viscosity in collagen gel, but the effect is negligible for thin film. Relaxation time distribution spectrum was obtained from the stress relaxation data by inverse Laplace transform. For most of the collagen matrices, three peaks at the short (0.3s ~1 s), medium (3s ~90 s), and long relaxation time (> 200 s) were observed in the continuous spectrum, which likely corresponds to relaxation mechanisms involve fiber, inter-fibril, and fibril sliding. Splitting of the middle peak was observed at higher initial stress levels suggesting increased structural heterogeneity at the fibril level with mechanical loading. The intensity of the long-term peaks increases with higher initial stress levels indicating the engagement of collagen fibrils at higher levels of tissue strain.

The influence of various rehydration protocols on biomechanical properties of different acellular tissue matrices

“…Our tension results indicate good agreement with previous studies that demonstrated a significant decrease in mechanical properties Representative DSC thermograms of MD (a) and DM (b) in either the dry or rehydrated state of collagen matrices going from the dry to the wet state [18,19]. The present study did not determine the specific mechanism for the change in mechanical properties following rehydration of the different collagen matrices.…”

Tissue Strain Reorganizes Collagen With a Switchlike Response That Regulates Neuronal Extracellular Signal-Regulated Kinase Phosphorylation In Vitro: Implications for Ligamentous Injury and Mechanotransduction

“…The greatest degrees of collagen fiber realignment and cell reorientation that occurred at the slow loading rate (Figs. 4 and 5) may be due to the viscoelastic properties of the neurons and their surrounding collagen matrix [75][76][77]. Viscoelasticity may limit fiber rotation and stretch during rapid NCC stretch because hydrogen bonds between and within the collagen molecules are less likely to break under rapid loading [78,79].…”

“…Since the nonlinear properties of collagen and neurons can induce higher stress and less stress relaxation in tissue undergoing more rapid stretch [5,77,80], neurons stretched at the fast rate were hypothesized to experience greater loads and to exhibit elevated activity compared to those undergoing slower loading. However, no difference in pERK production was observed between the two rates, regardless of the distraction magnitude (Fig.…”

Effect of curcumin caged silver nanoparticle on collagen stabilization for biomedical applications

“…The solutions were kept overnight with continuous stirring at 4º C before performing the measurements with and without CCSNP for cross-linking [47].…”