title: X-ray photoelectron spectroscopic and Raman analysis of silk fibroin-Cu(II) films.
abstract: There is evidence to suggest that Cu(II) is involved in the natural spinning process of a silkworm helping to convert the concentrated silk fibroin (SF) solution (or dope) into tough insoluble threads. To investigate the interaction between SF and Cu(II), a series of regenerated SF (RSF) films with different mass ratios of Cu(II) to SF were prepared. X-ray photoelectron spectroscopy (XPS) was employed to study the chemical interaction between Cu(II) and SF in these Cu(II)-RSF films. A significant change in the binding energy of Cu 2p(3/2) demonstrated that the chemical state of Cu(II) in the Cu(II)-RSF films was affected by the interaction between Cu(II) and SF. Moreover, chemical shifts of N 1s and O 1s of SF were also detected, implying that Cu(II) may coordinate with both N and O atoms in the SF. In addition, Raman spectra of the same series of Cu(II)-RSF films recorded the conformation transition of SF that may occur by the coordination of Cu(II) and SF macromolecular chains.
authors.affiliation: The Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhou
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Weilin
authors.initials: W
authors.lastname: Dai
authors.forename: Zhengzhong
authors.initials: Z
authors.lastname: Shao
mesh_terms: D000818:Animals; D012831:Bombyx / Q000737:chemistry; D003300:Copper / Q000032:analysis*; D005349:Fibroins / Q000032:analysis*; D019476:Insect Proteins / Q000032:analysis*; D011487:Protein Conformation; D047011:Silk / Q000032:analysis*; D013052:Spectrometry, X-Ray Emission; D013059:Spectrum Analysis, Raman
chemical_list: D019476:Insect Proteins; D047011:Silk; D003300:Copper; D005349:Fibroins