Authors: F. Gobeaux, G. Mosser, A. Anglo, P. Panine, P. Davidson, M.-M. Giraud-Guille, E. Belamie
Affilation: Ecole Pratique des Hautes Etudes, France
Pages: 218 - 221
Keywords: collagen, liquid crystal, fibrillogenesis, self-assembly, TEM, X-ray scattering
Dense ordered collagen matrices can be obtained by fine tuning the electrostatic interactions in highly concentrated solutions of type I collagen. Such biomimetic fibrillar materials have a high application potential in the field of tissue engineering, owing to their structural similarity with major biological tissues like bone, cornea, tendon and skin. We have demonstrate that an isotropic-to-cholesteric (I/N*) phase transition occurs at critical concentrations of 50-60 mg/mL to 80-85 mg/mL depending on the solvent. In such concentrated solutions, interparticle scattering gives rise to a broad interference peak that we studied by SAXS. Equilibrium concentrations and the order parameter of the nematic phase agree reasonably well with theoretical predictions for semiflexible macromolecules. We found that fibrillar aggregates form in acidic solutions at collagen concentrations above 150 mg/mL, which suggests a N*/SmA transition. In the same concentration range, we explored the structure of gels obtained at neutral pH. The typical cross-striated pattern in TEM and the corresponding SAXS 67-nm diffraction peaks were visible in all conditions. Collagen concentration greatly influences the overall macroscopic structure of the resultant fibrillar gels, as well as the morphology and structure of the fibrils themselves.