title: Electron microscopic determination of silver incorporation in collagen fibers as a model of organic-metal chiral supramolecular structure with optical anisotropic properties.
abstract: The high positive linear dichroism (LD) exhibited by silver-impregnated collagen fibers are thought to be caused by an ordered binding of silver nanoparticles to the collagen fibers. A correlation between LD, established by image analysis, and the size of silver particles as measured by electron microscopy was investigated in the same sections of silver-impregnated tendon collagen fibers. Silver particles were found to be periodically ordered along the collagen fibers, with some preference for the 67 nm collagen period and collagen a bands. The silver particle diameter for a sample of n=279 was 18.51 nm on average, with 95% of the values ranging between 17.90 and 19.14 nm. The finding that interference colors are correlated to abnormal dispersion of birefringence characteristics supports the concept that collagen fibers induce an ordered binding of silver distributed along the fibers.
authors.affiliation: Department of Cell Biology, Institute of Biology, State University of Campinas, P.O. Box 6109, 13083-970, SP, Campinas, Brazil. vidal@obelix.unicamp.br
authors.forename: Benedicto De Campos
authors.initials: Bde C
authors.lastname: Vidal
authors.forename: Paulo
authors.initials: P
authors.lastname: Joazeiro
mesh_terms: D000818:Animals; D016880:Anisotropy; D001718:Birefringence; D002417:Cattle; D003094:Collagen / Q000737:chemistry* / Q000648:ultrastructure*; D004396:Coloring Agents; D066298:In Vitro Techniques; D008854:Microscopy, Electron / Q000379:methods*; D015394:Molecular Structure; D012834:Silver; D013710:Tendons / Q000737:chemistry / Q000648:ultrastructure
chemical_list: D004396:Coloring Agents; D012834:Silver; D003094:Collagen