Microbial Bioavailability of Covalently Bound Polymer Coatings on Model Engineered Nanomaterials

• Published in: Environmental science & technology Vol. 45; no. 12; pp. 5253 - 5259
• Main Authors: Kirschling, Teresa L, Golas, Patricia L, Unrine, Jason M, Matyjaszewski, Krzysztof, Gregory, Kelvin B, Lowry, Gregory V, Tilton, Robert, D
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.06.2011
• Subjects: Adsorption - drug effects; Applied sciences; Bacteria - drug effects; Bacteria - metabolism; Bacteria - ultrastructure; Bacterial Proteins - biosynthesis; Bioavailability; Biodegradation; Biological and physicochemical phenomena; Biological and physicochemical properties of pollutants. Interaction in the soil; Biological Availability; Carbon; Carbon dioxide; Coated Materials, Biocompatible - pharmacology; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Processes; Exact sciences and technology; Hydrodynamics; Models, Chemical; Nanomaterials; Nanoparticles; Nanoparticles - ultrastructure; Nanostructures - chemistry; Nanostructures - ultrastructure; Nanotechnology - methods; Natural water pollution; Pollution; Pollution, environment geology; Polyethylene Glycols - chemistry; Polymers; Polymers - pharmacology; Proteins; Soil and sediments pollution; Water treatment and pollution; Pollutant behavior; Nanoparticle; Bioavailability; Coatings; Ethylene oxide polymer; Pollution; Stabilizer agent; Model compound; Covalent bond; Coated particle; Environment; Microorganism; Nanostructured materials; Nanotechnology
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es200770z

By controlling nanoparticle flocculation and deposition, polymer coatings strongly affect nanoparticle fate, transport, and subsequent biological impact in the environment. Biodegradation is a potential route to coating breakdown, but it is unknown whether surface-bound polymers are bioavailable. Here we demonstrate, for the first time, that polymer coatings covalently bound to nanomaterials are bioavailable. Model poly(ethylene oxide) (PEO) brush-coated nanoparticles (densely cross-linked bottle brush copolymers) with hydrophobic divinyl benzene cross-linked cores and hydrophilic PEO brush shells, having ∼30 nm hydrodynamic radii, were synthesized to obtain a nanomaterial in which biodegradation was the only available coating breakdown mechanism. PEO-degrading enrichment cultures were supplied with either PEO homopolymer or PEO brush nanoparticles as the sole carbon source, and protein and CO2 production were monitored as a measure of biological conversion. Protein production after 90 h corresponded to 14% and 8% of the total carbon available in the PEO homopolymer and PEO brush nanoparticle cultures, respectively, and CO2 production corresponded to 37% and 3.8% of the carbon added to the respective system. These results indicate that the PEO in the brush is bioavailable. Brush biodegradation resulted in particle aggregation, pointing to the need to understand biologically mediated transformations of nanoparticle coatings in order to understand the fate and transport of nanoparticles in the environment.