EFFECTS OF STATIC AXIAL STRAIN ON THE TENSILE PROPERTIES AND FAILURE MECHANISMS OF SELF-ASSEMBLED COLLAGEN-FIBERS

Collagen fibers form the structural units of connective tissue through out the body, transmitting force, maintaining shape, and providing a s caffold for cells. Our laboratory has studied collagen self-assembly s ince the 1970s. In this study, collagen fibers were self-assembled fro m molecular collagen solutions and then stretched to enhance alignment . Fibers were tested in uniaxial tension to study the mechanical prope rties and failure mechanisms. Results reported suggest that axial orie ntation of collagen fibrils can be achieved by stretching uncrosslinke d collagen fibers. Stretching by about 30% not only results in decreas ed diameter and increased tensile strength but also leads to unusual f ailure mechanisms that inhibit crack propagation across the fiber. It is proposed that stretching serves to generate oriented fibrillar subs tructure in self-assembled collagen fibers. (C) 1997 John Wiley & Sons , Inc.