Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/196233
Type: Artigo
Title: Supramolecular order following binding of the dichroic birefringent sulfonic dye Ponceau SS to collagen fibers
Author: Vidal, B. C.
Mello, M. L. S.
Abstract: The optical anisotropies (linear dichroism or LD and birefringence) of crystalline aggregates of the sulfonic azo-dye Ponceau SS and of dye complexed with chicken tendon collagen fibers were investigated in order to assess their polarizing properties and similarity to liquid crystals. In some experiments, the staining was preceded by treatment with picric acid. Crystalline fibrous aggregates of the dye had a negative LD, and their electronic transitions were oriented perpendicular to the filamentary structures. The binding of Ponceau SS molecules to the collagen fibers altered the LD signal, with variations in the fiber orientation affecting the resulting dichroic ratios. The long axis of the rod-like dye molecule was assumed to be bound in register, parallel to the collagen fiber. Picric acid did not affect the oriented binding of the azo dye to collagen fibers. There were differences in the optical anisotropy of Ponceau SS-stained tendons from 21-day-old and 41-day-old chickens, indicating that Ponceau SS was able to distinguish between different ordered states of macromolecular aggregation in chicken tendon collagen fibers. In the presence of dichroic rod-like azo-dye molecules such as Ponceau SS, collagen also formed structures with a much higher degree of orientation. The presence of LD in the Ponceau SS-collagen complex even in unpolarized light indicated that this complex can act as a polarizer.
The optical anisotropies (linear dichroism or LD and birefringence) of crystalline aggre-gates of the sulfonic azo-dye Ponceau SS and of dye complexed with chicken tendon collagen fiberswere investigated in order to assess their polarizing properties and similarity to liquid crystals. Insome experiments, the staining was preceded by treatment with picric acid. Crystalline fibrous aggre-gates of the dye had a negative LD, and their electronic transitions were oriented perpendicular tothe filamentary structures. The binding of Ponceau SS molecules to the collagen fibers altered the LDsignal, with variations in the fiber orientation affecting the resulting dichroic ratios. The long axis ofthe rod-like dye molecule was assumed to be bound in register, parallel to the collagen fiber. Picricacid did not affect the oriented binding of the azo dye to collagen fibers. There were differences in theoptical anisotropy of Ponceau SS-stained tendons from 21-day-old and 41-day-old chickens, indicat-ing that Ponceau SS was able to distinguish between different ordered states of macromolecularaggregation in chicken tendon collagen fibers. In the presence of dichroic rod-like azo-dye moleculessuch as Ponceau SS, collagen also formed structures with a much higher degree of orientation. Thepresence of LD in the Ponceau SS-collagen complex even in unpolarized light indicated that this com-plex can act as a polarizer.
Subject: Fibra de colágeno
Cristais líquidos
Anisotropia
Birrefringência
Compostos azo
Galinha
Country: Estados Unidos
Editor: John Wiley & Sons
Citation: Biopolymers. v. 78, n. 3, p. 121-8, 2005-Jun.
Rights: aberto
Identifier DOI: 10.1002/bip.20274
Address: https://onlinelibrary.wiley.com/doi/abs/10.1002/bip.20274
Date Issue: 2005
Appears in Collections:IB - Artigos e Outros Documentos

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