Effect of pH on dimensional stability of rat tail tendon collagen fiber

Abstract

The organized molecular structure of collagen is related to its dimensional stability. The dimensional stability of collagen arises from the interplay of various intermolecular forces such as covalent, hydrogen bonding, electrostatic interactions, hydrophobic interactions, London or van der Waals forces, and weak interactions. A structure-function relationship exists in collagen. Electrostatic interactions play an important role in dimensional stabilization. The dimensional stability of rat tail tendon (RTT) collagen fiber is affected by the change in the net fixed charge on the molecule as a function of pH. Thermal and mechanical properties are dependent on molecular and lattice orders. The pH dependence of thermal shrinkage, isometric tension, differential scanning calorimetry, swelling behavior, tensile strength, and percent extension and stress relaxation behavior are studied in 0.02M Tris-maleate buffer at pH 4 -8. The observed experimental results provide compelling evidence that electrostatic interactions play an important role in the dimensional stability of RTT collagen.

Strategies for directing the structure and function of three-dimensional collagen biomaterials across length scales

“…Varying the pH and temperature during gel formation has been shown to affect the structure of collagen gels. Lower pH leads to more compliant materials with decreased fibril diameter [28, 29], possibly due to protonation of the COOH groups and a consequent reduction in interactions between the carboxyl and amino acid groups [30]. Higher temperatures affect the structure of nascent collagen by providing energy to increase the rate of fibrillogenesis and decrease both the diameter of the fibers [31] and the pore size in the meshes [32], which can result in increased mechanical properties [33].…”

Role of Secondary Structure on the Stress Relaxation Processes in Rat Tail Tendon (RTT) Collagen Fibre

“…The effect of pH on the dimensional stability of RTT collagen fibre has been reported earlier. [36] Role of Solvents…”

pH-induced contrast in viscoelasticity imaging of biopolymers

“…For gelatin gels IEP = 5.6 and for collagen IEP ≃ 7 (Usha and Ramasami, 2000; Highberger, 1939). The observed pH effects on mechanical properties are predominantly elastic, which is consistent with the literature describing how pH can influence the molecular structure of collagen.…”

“…Increasing or decreasing the pH from the IEP degrades the gelatin molecules, although the amount of degradation is greater for acidic gels (Mohanty et al, 2007), resulting in shorter gelatin fragments. pH adjustments also induce structural changes in collagen (Usha and Ramasami, 2000; Roeder et al, 2002; Seehra and Silver, 2006). Roeder et al (2002) found that an increase in pH produced fibrils of longer length, while a decrease in pH resulted in shorter collagen fibrils.…”

“…Variations in pH from the isoelectric pH (IEP) value† are also known to alter the matrix structure of many hydropolymers (Veis, 1964), including connective tissues, and thus the VE properties (Usha and Ramasami, 2000; Roeder et al, 2002; Seehra and Silver, 2006). Isolated extracellular matrix proteins have a net negative surface charge.…”