Electromechanical properties of dried tendon and iso-electrically focused collagen hydrogels

Assembling artificial collagenous tissues with
structural, functional, and mechanical properties which mimic natural
tissues is of vital importance for many tissue engineering applications.
While the electro-mechanical properties of collagen are thought to play
a role in, for example, bone formation and remodeling, this functional
property has not been adequately addressed in engineered tissues. Here
the electro-mechanical properties of rat tail tendon are compared with
those of dried isoelectrically focused collagen hydrogels using
piezoresponse force microscopy under ambient conditions. In both the
natural tissue and the engineered hydrogel D-periodic type I collagen
fibrils are observed, which exhibit shear piezoelectricity. While both
tissues also exhibit fibrils with parallel orientations, Fourier
transform analysis has revealed that the degree of parallel alignment of
the fibrils in the tendon is three times that of the dried hydrogel.
The results obtained demonstrate that isoelectrically focused collagen
has similar structural and electro-mechanical properties to that of
tendon, which is relevant for tissue engineering applications.