Chirality and helicity of poly-benzyl-L-glutamate in liquid crystals and a wave structure that mimics collagen helicity in crimp

• Autor(a) principal: Vidal,Benedicto de Campos
• Data de Publicação: 2001
• Outros Autores: Mello,Maria Luiza Silveira
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Materials research (São Carlos. Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392001000300005
• topic: poly-benzyl-L-glutamate; wave-like superstructure; liquid crystal; optical anisotropy

Ideal biocompatible polymers must show a mimetic superstructure with biological supra-organization. Collagen-rich structures like tendons and ligaments are materials with various levels of order, from molecules to bundles of fibers, which affect their biomechanical properties and cellular interactions. Poly-benzyl-L-glutamate (PBLG) displaying helicity was used here to test the development of wave-like structures as those occurring in collagen fibers. Birefringence of PBLG under various crystallization conditions was studied with a lambda/4 compensator according to Sénarmont. Qualitative observations were plainly sufficient to conclude that the PBLG fibrils were supra-organized helically as a chiral object. During crystallization stretched PBLG formed a helical superstructure with characteristic striation resembling waves (crimp). Supported by optical anisotropy findings, a twisted grain boundary liquid crystal type is proposed as a transition phase in the formation of the PBLG chiral object. A similarity with the wavy organization (crimp) of collagen bundles is proposed.