TY - THES
AU - Lam, Luk Sang
PY - 1988
TI - Flow conductivity of solutions of hyaluronic acid : effects of concentration and molecular weight
KW - Thesis/Dissertation
LA - eng
M3 - Text
AB - Hyaluronic acid plays an important role in regulating the transport of fluid and solutes in the interstitium. The concentration and molecular weight of hyaluronic acid in different connective tissues are different. These factors influence the hydraulic flow conductivity, K', of connective tissues. An experimental study of the effect of concentration and molecular weight of hyaluronic acid on the hydraulic flow conductivity is the subject of this work.
Hyaluronic acid of different molecular weights were obtained by
fractionating commercially available hyaluronic acid using ion-exchange column
chromatography. The results were not reproducible, partly because of the elution
process was not continuous. Nevertheless, three molecular weight fractions
(6.99 to 11.1 X 10⁵ ) were obtained. Hyaluronic acid of lower molecular weights (0.454 to 1.65 X 10⁵) were obtained by acid hydrolysing some of the chromatographed fractions for 15 min., 1 hour and 2 hours. A more homogeneous hyaluronic acid fraction (M.W. = 1.96 X10⁵) was obtained by fractionating hyaluronic acid materials acid hydrolysed for 15 min.
The hydraulic flow conductivity of solutions of hyaluronic acid can be calculated from the sedimentation coefficient of the solutions at 20°C, S₂₀‚ measured by ultracentrifugation. Centrifugation experiments determining the S₂₀ of the molecular weight fractions of hyaluronic acid at various concentrations were therefore undertaken. The results showed that S₂₀ decreased with increased
concentration of hyaluronic acid. Also, the curves of as a function of
hyaluronic acid concentration, c, converged at high concentration, indicating that a three dimensional molecular network is formed at high concentration and the
extent of entanglement between molecules is the same for the high and low
M.W. fractions. At lower concentrations, for the acid hydrolysed fractions, S₂₀
increased with M.W., which is in agreement with past sedimentation data. For
the non-acid hydrolysed fractions, the difference in S₂₀ between two higher M.W.
fractions is small, and the lowest M.W. fraction has consistently higher S₂₀ than
the higher M.W. fractions. This finding does not agree with past literature
results, and the difference in results is most probably due to experimental errors.
However, when the fractionated non-acid hydrolysed fractions are taken as a high M.W. group (M.W. = 6.99 to 11.1X10⁵) and the acid hydrolysed fractions as a low M.W. group (M.W. = 0.454 to 1.96X10⁵), the curves of S₂₀ as a function of c of the low M.W. group fall below those of the high M.W. group, which is in agreement with past sedimentation data.
The hydraulic conductivities (K'), calculated from S₂₀ data, for all the HA fractions varied inversely with concentration. The log-log plots of K' versus c compared well with the results of Ethier (1986). The K' versus c relationships for all the fractions converged at high concentrations. At low concentrations, the HA molecules of the high M.W. group has a higher K' than those of the low M.W. group.
N2 - Hyaluronic acid plays an important role in regulating the transport of fluid and solutes in the interstitium. The concentration and molecular weight of hyaluronic acid in different connective tissues are different. These factors influence the hydraulic flow conductivity, K', of connective tissues. An experimental study of the effect of concentration and molecular weight of hyaluronic acid on the hydraulic flow conductivity is the subject of this work.
Hyaluronic acid of different molecular weights were obtained by
fractionating commercially available hyaluronic acid using ion-exchange column
chromatography. The results were not reproducible, partly because of the elution
process was not continuous. Nevertheless, three molecular weight fractions
(6.99 to 11.1 X 10⁵ ) were obtained. Hyaluronic acid of lower molecular weights (0.454 to 1.65 X 10⁵) were obtained by acid hydrolysing some of the chromatographed fractions for 15 min., 1 hour and 2 hours. A more homogeneous hyaluronic acid fraction (M.W. = 1.96 X10⁵) was obtained by fractionating hyaluronic acid materials acid hydrolysed for 15 min.
The hydraulic flow conductivity of solutions of hyaluronic acid can be calculated from the sedimentation coefficient of the solutions at 20°C, S₂₀‚ measured by ultracentrifugation. Centrifugation experiments determining the S₂₀ of the molecular weight fractions of hyaluronic acid at various concentrations were therefore undertaken. The results showed that S₂₀ decreased with increased
concentration of hyaluronic acid. Also, the curves of as a function of
hyaluronic acid concentration, c, converged at high concentration, indicating that a three dimensional molecular network is formed at high concentration and the
extent of entanglement between molecules is the same for the high and low
M.W. fractions. At lower concentrations, for the acid hydrolysed fractions, S₂₀
increased with M.W., which is in agreement with past sedimentation data. For
the non-acid hydrolysed fractions, the difference in S₂₀ between two higher M.W.
fractions is small, and the lowest M.W. fraction has consistently higher S₂₀ than
the higher M.W. fractions. This finding does not agree with past literature
results, and the difference in results is most probably due to experimental errors.
However, when the fractionated non-acid hydrolysed fractions are taken as a high M.W. group (M.W. = 6.99 to 11.1X10⁵) and the acid hydrolysed fractions as a low M.W. group (M.W. = 0.454 to 1.96X10⁵), the curves of S₂₀ as a function of c of the low M.W. group fall below those of the high M.W. group, which is in agreement with past sedimentation data.
The hydraulic conductivities (K'), calculated from S₂₀ data, for all the HA fractions varied inversely with concentration. The log-log plots of K' versus c compared well with the results of Ethier (1986). The K' versus c relationships for all the fractions converged at high concentrations. At low concentrations, the HA molecules of the high M.W. group has a higher K' than those of the low M.W. group.
UR - https://open.library.ubc.ca/collections/831/items/1.0058822
ER - End of Reference