TY - JOUR
T1 - Anisotropic structure of calcium-induced alginate gels by optical and small-angle X-ray scattering measurements
AU - Maki, Yasuyuki
AU - Ito, Kei
AU - Hosoya, Natsuki
AU - Yoneyama, Chikayoshi
AU - Furusawa, Kazuya
AU - Yamamoto, Takao
AU - Dobashi, Toshiaki
AU - Sugimoto, Yasunobu
AU - Wakabayashi, Katsuzo
PY - 2011/6/13
Y1 - 2011/6/13
N2 - It was more than 50 years ago that an appearance of birefringence in alginate gels prepared under cation flow was reported for the first time, however, the anisotropic structure of the alginate gel has not been studied in detail. In the present study, anisotropic Ca-alginate gels were prepared within dialysis tubing in a high Ca2+-concentration external bath, and optical and small-angle X-ray scattering (SAXS) measurements were performed to characterize the structure of the gel. The observations of the gel with crossed polarizers and with circular polarizers revealed the molecular orientation perpendicular to the direction of Ca2+ flow. Analyses of the SAXS intensity profiles indicated the formation of rod-like fibrils consisting of a few tens of alginate molecules and that the anisotropy of the gel was caused by the circumferential orientation of the large fibrils. From the observed asymmetric SAXS pattern, it was found that the axis of rotational symmetry of the anisotropic structure was parallel to the direction of Ca2+ flow. The alignment factor (Af) calculated from the SAXS intensity data confirmed that the orientation of the fibrils was perpendicular to the direction of Ca2+ flow.
AB - It was more than 50 years ago that an appearance of birefringence in alginate gels prepared under cation flow was reported for the first time, however, the anisotropic structure of the alginate gel has not been studied in detail. In the present study, anisotropic Ca-alginate gels were prepared within dialysis tubing in a high Ca2+-concentration external bath, and optical and small-angle X-ray scattering (SAXS) measurements were performed to characterize the structure of the gel. The observations of the gel with crossed polarizers and with circular polarizers revealed the molecular orientation perpendicular to the direction of Ca2+ flow. Analyses of the SAXS intensity profiles indicated the formation of rod-like fibrils consisting of a few tens of alginate molecules and that the anisotropy of the gel was caused by the circumferential orientation of the large fibrils. From the observed asymmetric SAXS pattern, it was found that the axis of rotational symmetry of the anisotropic structure was parallel to the direction of Ca2+ flow. The alignment factor (Af) calculated from the SAXS intensity data confirmed that the orientation of the fibrils was perpendicular to the direction of Ca2+ flow.
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U2 - 10.1021/bm200223p
DO - 10.1021/bm200223p
M3 - Article
C2 - 21504159
AN - SCOPUS:79958817108
VL - 12
SP - 2145
EP - 2152
JO - Biomacromolecules
JF - Biomacromolecules
SN - 1525-7797
IS - 6
ER -