Sodium hyaluronate studied for the relationship between structural properties and functionality
1999
Nakamura, K. (College of Dairying, Ebetsu, Hokkaido (Japan)) | Shiota, T. | Ogino, K. | Nishinari, K. | Ogawa, E. | Okamoto, A. | Kubota, K. | Hiranuma, M. | Yomota, C.
Sodium hyaluronate (HA), a linear polyelectrolyte consisting of the disaccharides repeating unit of D-glucuronate and N-acetyl-D-glucosamine, is an important component of biomaterials, such as rooster comb, vitreous humor, and synovial fluid. Because of its remarkable viscoelasticity, in synovial fluid HA plays an important role as a lubricant of joints. HA also occurs in the culture medium of bacteria. In the present study, we measured the viscosity of the solutions of two types of sodium hyaluronate, namely, HA (H-HA) extracted from rooster comb and HA (D-HA) produced by the bacteria. To elucidate the physioc-chemical properties of HA solutions, we compared the effects of bovine serum albumin (BSA) and of several sugars on the viscosity of the two HA solutions. The samples used were as 1 % phosphate buffer solution (PBS), and the viscosities was determined by using a Ubbelohde-type viscometer. The intrinsic viscosity of the D-HA solution are 29.4 wt%-1 at 25 degrees C, and that of the H-HA was l4.2. With increasing BSA concentration, initially the reduced viscosities rose rather abruptly, then decreased gradually. This feature may be interpreted as an increase in electrostatic interactions between HA segments and the BSA, as elicited the BSA concentration. On the other band, with increasing concentration of sugar (glucose, fructose, sucrose) concentrations, the reduced viscosity increased in a range from 0 to ca. 0.1mol/l. The tendency of the 1-educed viscosity of the D-HA to increase occurred with fructose sucrose glucose = water, whereas that of the H-HA occurred with fructose = sucrose glucose = water. These results suggest a marked interactions between hyaluronic acid and water, a rationale borne out by the wen known role of HA as a lubricant in synovial fluid
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