BANDED PATTERNS IN LIQUID-CRYSTALLINE PHASES OF TYPE-I COLLAGEN - RELATIONSHIP WITH CRIMP MORPHOLOGY IN CONNECTIVE-TISSUE ARCHITECTURE

Solutions of type I acid soluble collagen were studied in light and el ectron microscopy at concentrations over 40 mg/ml. Banded patterns spo ntaneously emerge in samples observed between crossed polars between s lide and coverslip. The textures are interpreted as precholesteric, ap pearing at the transition between the isotropic phases, due to random molecular order, and the cholesteric phase corresponding to a highly o rganized three-dimensional structure. Type I collagen banded patterns correspond to regular undulations of the molecular directions with an observed periodicity in the range of 1 to 10 mu m. This interpretation is verified by ultrastructural analysis of precholesteric samples gel led under ammonium vapors. Results are discussed in regard to banded p atterns described either within synthetic polymer systems or within co llagen extracellular matrices. self-assembled liquid crystalline phase s of collagen generate crimp morphologies. Their possible relationship with early secretion steps in the development of connective tissues i s discussed.