From collagen type I solution to fibers with a helical pattern: a self-assembly phenomenon.

To determine whether collagen solubilized from tendons can regenerate the most relevant characteristics of the tendon supraorganization was the aim of the present study. Extracted and purified collagen in acetic acid solutions subjected to precipitation and extensive dialysis was found to produce gels with rheological properties that allowed them to form threads and rubber-like rods. Molecular order and the ordered aggregational state of the fibers were detected by optical anisotropy at the polarization microscope. Self-assembly and self-organization resulted in a supraorganized structure in which the fibers are ordered parallel to the long axis of the thread or the rod, and in an intertwined helical organization. The highly birefringent fibers and their geometrically ordered self-organization resembled the original tendons. Some questions related to morphogenesis, recognition and adhesion events, biomechanical properties of collagen-containing structures and development of biomaterial for medical use may be answered by this model. In terms of perspectives it would be important to consider collagen fibers as models for producing organic-inorganic interface depositions to achieve optical properties.