Ralph Colby

Protein Aggregation

Globular proteins are polymers that are collapsed into compact structures in aqueous media. Common globular proteins are albumin and globulins that are found in blood and the synovial fluid that lubricates motion of mammalian joints.

The goal of this research is to understand protein aggregation in physiological conditions. Synovial fluid seems to have its lubrication properties controlled by protein aggregation. Arthritis and other joint maladies are likely affected by this protein aggregation, so we need to understand it.

Statement of Work

The student will complete the following tasks during the research:

  • Measure viscosity of albumin solutions under physiological conditions in the presence of various additives such as calcium ions, anti-inflammatory drugs, and other biopolymers found within the synovium. We will use simple viscosity measurements as a screening tool to decide which additives affect aggregation.
  • For the additives that either promote or discourage aggregation, quantify the extent of aggregation using small-angle x-ray scattering measurements (using the state-of-the-art SAXS beamline shown below, in Hosler Building).
  • Find and read the relevant literature on protein aggregation, anti-inflammatory drugs and synovial fluid.
  • Work with MedImmune scientists and Penn State graduate students on models for protein aggregation.

Related Publications

  1. Katherine M. N. Oates, Wendy E. Krause, Ronald L. Jones and Ralph H. Colby, “Rheopexy of synovial fluid and protein aggregation,” J. R. Soc. Interface, 2006, 3, 167-174.
  2. Maria Monica Castellanos, Jai A. Pathak and Ralph H. Colby, “Both protein adsorption and aggregation contribute to shear yielding and viscosity increase in protein solutions,” Soft Matter, 2014, 10, 122.

colby model 2

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Contact Information

Ralph Colby, Ph.D.
Professor of Materials Science and Engineering and Chemical Engineering



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