Ionic strength effect on molecular structure of hyaluronic acid investigated by flow field-flow fractionation and multiangle light scattering

Bitnara Kim, Sohee Woo, Young Soo Park, Euijin Hwang, Myeong Hee Moon

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

This study describes the effect of ionic strength on the molecular structure of hyaluronic acid (HA) in an aqueous solution using flow field-flow fractionation and multiangle light scattering (FlFFF-MALS). Sodium salts of HA (NaHA) raw materials (∼2∈×∈106 Da) dispersed in different concentrations of NaCl prepared by repeated dilution/ultrafiltration procedures were examined in order to study conformational changes in terms of the relationship between the radius of gyration and molecular weight (MW) and molecular weight distribution (MWD) of NaHA in solution. This was achieved by varying the ionic strength of the carrier solution used in a frit-inlet asymmetrical FlFFF (FIAF4) channel. Experiments showed that the average MW of NaHA increased as the ionic strength of the NaHA solution decreased due to enhanced entanglement or aggregation of HA molecules. Relatively large molecules (greater than ∼5 MDa) did not show a large increase in RMS radius value as the NaCl concentration decreased. Conversely, smaller species showed larger changes, suggesting molecular expansion at lower ionic strengths. When the ionic strength of the FlFFF carrier solution was decreased, the HA species in a salt-rich solution (0.2 M NaCl) underwent rapid molecular aggregation during FlFFF separation. However, when salt-depleted HA samples (I∈=∈4.66∼0.38 mM) were analyzed with FFF carrier solutions of a high ionic strength, the changes in both molecular structure and size were somewhat reversible, although there was a delay in correction of the molecular structure.

Original languageEnglish
Pages (from-to)1327-1334
Number of pages8
JournalAnalytical and Bioanalytical Chemistry
Volume407
Issue number5
DOIs
Publication statusPublished - 2015 Feb 6

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry

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