Understanding and Quantifying the Role of Polyethylene Photodegradation in Altering Protein Adsorption.

Abstract

Due to its desirable physical and chemical characteristics and low production costs, plastics have become an extremely desirable product for both industrial and consumer purposes. However, due to these same desirable characteristics and improper disposal avenues, plastics have become an environmental concern, particularly their impact on ecosystems. Once plastics enter the environment, there are synergistic driving forces that cause weathering. While many of the degradation pathways of polymers in the environment are well documented the interplay between abiotic and biotic degradation are not well understood. In this work, the role of polyethylene’s photodegradation on protein adsorption are investigated. Protein adsorption is a key step in biofilm formation and biotic degradation of polymers. This work specifically focuses on the model protein BSA and its adsorption to PE. Through investigative spectroscopic techniques (i.e., fluorescence and circular dichroism), it was shown that an increase in hydrophilicity caused by photodegradation of the polymers’ surface, caused less perturbation of the local environment of the tryptophan residues. It was also observed that there was larger structural frustration and rearrangement of the protein upon binding to PE at points during photodegradation, where there were significant changes in the chemical and physical properties. Depending on the inherent protein stability, larger structural changes upon surface binding indicate an increase in adsorption strength. Environmentally, this signifies an increase in biofilm strength at the transition points in polymer photodegradation leading to a potential increase in the rate of biodegradation.