Chemical Changes Over Time Associated with Protein Drying.

Upon drying, physical changes of the characteristics of proteins are observed by coagulation, but the nature and chronology of these changes have not been well studied. Coagulation changes the structure of protein from liquid to a solid or a thicker liquid by heat, mechanical action, or acids. Changes may have implications regarding the cleanability of reusable medical devices; therefore, an understanding of the chemical phenomena associated with drying of proteins is essential to ensuring adequate cleaning and mitigation of retained surgical soils. Using a high-performance gel permeation chromatography analysis with right-angle light-scattering detector at 90°, it was demonstrated that as soils dry, the molecular weight distribution changes. From the experimental evidence, the molecular weight distribution trends over time with drying to higher values. This is interpreted as a combination of oligomerization, degradation, and entanglement. As water is removed through evaporation, the distance between proteins decreases and their interactions increase. Albumin will polymerize into higher-molecular-weight oligomers, decreasing its solubility. Mucin, commonly found in the gastrointestinal tract to prevent infection, will degrade in the presence of enzymes releasing low-molecular-weight polysaccharides and leaving behind a peptide chain. The research described in this article investigated this chemical change.