Instrument combination characterizes biopolymers in new ways

Using a combination of instruments, Wyatt Technology is exploring the material characteristics of the biopolymer, hyaluronic acid (HA). With its ViscoStar, Dawn EOS, and Optilab rEX in series, the company has overcome consistent problems experienced using other techniques to accurately calculate characteristics of HA.

By Control Engineering Staff February 17, 2005

Using a combination of instruments, Wyatt Technology is exploring the material characteristics of the biopolymer, hyaluronic acid (HA). With its ViscoStar, Dawn EOS, and Optilab rEX in series, the company has overcome consistent problems experienced using other techniques to accurately calculate characteristics of HA. A naturally occurring polymer, HA is present in mammalian systems and is of significant interest for a variety of medical, pharmacological, and cosmetic applications.

HA has been studied using size-exclusion chromatography (SEC) and, more recently, single-capillary viscometry (SCV). However, SCV is vulnerable to noise generated by system pressure fluctuations. Even slight changes in flow rate can lead to increased baseline noise that lowers the signal-to-noise ratio (S:N) and, in turn, lowers experimental accuracy. Using the combined instrument collection with SEC overcomes such problems, producing an extremely high S:N and permitting more reliable exploration of HA material characteristics.

Chromatogram of a hyaluronic acid sample is determined using Wyatt Technology instrument range.

ViscoStar online differential viscometer, which incorporates a four-arm “bridge” design, was used to directly determine the sample specific viscosity. Optilab rEX was used for concentration measurements, and, combined with the ViscoStar, allows direct calculation of sample intrinsic viscosity. Dawn EOS allows calculation of absolute molar mass without reference standards, column calibration, or “fudge factors.”

Experimental collection and data analyses were performed using the company’s Astra V software. Results determined the absolute HA molecular weight, molecular weight distribution, and radii information to be consistent with historical literature values.

Click here for more information about absolute macromolecular characterization and light-scattering instrumentation.

—Jeanine Katzel, senior editor, Control Engineering, jkatzel@reedbusiness.com