The Impacts of Polystyrene Nanoplastics on the Viability and Cellular Function of S.oneidensis (2020-02-28)

Abstract

The design of plastic materials, while resulting in highly useful and marketable products, has led to a challenging, long-term environmental problem. As advancements have been made in determining the fate and environmental role of plastic materials, the field of nanoplastics has gained increasing interest when considering their potential impact on local ecosystems. This work explores the impact of nanoplastic materials on viability and functionality of a model bacterial species. Specifically, Shewanella oneidensis were exposed to polystyrene(PS) nanoplastics and monitored for changes in viability using a growth based viability assay. The cell function of riboflavin secretion, a molecule secreted to serve in the terminal electron transport chain during metal reduction, was monitored with liquid chromatography. Upon 4, 8 or 12 hours of exposure, there were minimal changes in viability of the S. oneidensis; yet, the amount of riboflavin secreted varied when exposed to different concentrations of PS nanoplastic. The localization of the nanoplastics within or on the surface of the cells was pursued with mass spectrometry. ICP-MS results showed the presence of PS nanoplastics in the supernatant and associated with the bacterial cells. Taking the varied riboflavin secretion patterns and the strong association of the nanoplastics with the cell membrane, we have concluded that S. oneidensis could use nanoparticle polystyrene as a substrate. Through this work, valuable insight on the fate of nanoplastics in biological systems is provided through the investigation of the physical interactions between PS nanoplastics and S. oneidensis.