Development and Application of Nanoparticle-Nanopolymer Composite Spheres for the Study of Environmental Processes

Abstract

Plastics have long been an environmental contaminant of concern as both large-scale plastic debris and as micro- and nano-plastics with demonstrated wide-scale ubiquity. Research in the past decade has focused on the potential toxicological risks posed by microplastics, as well as their unique fate and transport brought on by their colloidal nature. These efforts have been slowed by the lack of analytical techniques with sufficient sensitivity and selectivity to adequately detect and characterize these contaminants in environmental and biological matrices. To improve analytical analyses, microplastic tracers are developed with recognizable isotopic, metallic, or fluorescent signatures capable of being identified amidst a complex background. Here we describe the synthesis, characterization, and application of a novel synthetic copolymer nanoplastic based on polystyrene (PS) and poly(2-vinylpyridine) (P2VP) intercalated with gold, platinum or palladium nanoparticles that can be capped with different polymeric shells meant to mimic the intended microplastic. In this work, particles with PS and polymethylmethacrylate (PMMA) shells are used to examine the behavior of microplastic particles in estuarine sediment and coastal waters. The micro- and nanoplastic tracers, with sizes between 300 and 500 nm in diameter, were characterized using multiple physical, chemical, and colloidal analysis techniques. The metallic signatures of the tracers allow for quantification by both bulk and single-particle inductively-coupled plasma mass spectrometry (ICP-MS and spICP-MS, respectively). As a demonstration of environmental applicability, the tracers were equilibrated with sediment collected from Bellingham Bay, WA, United States to determine the degree to which microplastics bind and sink in an estuary based of grain size and organic carbon parameters. In these experiments, between 80 and 95% of particles were found to associate with the sediment, demonstrative of estuaries being a major anticipated sink for these contaminants. These materials show considerable promise in their versatility, potential for multiplexing, and utility in studying micro- and nano-plastic transport in real-world environments.

Living in a transient world: ICP-MS reinvented via time-resolved analysis for monitoring single events

“…This way, different types of nanoplastics with sizes down to 50 nm can be counted. 168 Furthermore, the development of new metal-doped (e.g., Ir and Pd) micro-and nano-plastics 169,170 and of nanoparticle-nanopolymer composites 171,172 further contribute to the extension of the application range of this methodology, as it can play an important role in exposure and risk assessment studies.…”

Nanoplastics prepared with uniformly distributed metal-tags: a novel approach to quantify size distribution and particle number concentration of polydisperse nanoplastics by single particle ICP-MS

“…100 nm NPs with a smooth or "raspberry-like" morphology have been synthesized. Recently a more complex core shell NP was synthesized via intercalation of metal chloride salts (Au, Pd, or Pt) into a porous core 104 followed by the reduction of the salts to elemental metal. The metal-imbued core was then coated with either PMMA or PS.…”

Classification, synthesis, characterization, and applications of metal nanoparticle-containing hybrid microgels: a comprehensive review

“…Systems of MNPs-decorated polymers encapsulated by another organic polymer have been documented with only Pd 13 and Au 102 nanoparticles, and bimetallic nanoparticle-based hybrid systems of this class have not been reported yet. Furthermore, these hybrid microgels along with non-metal nanoparticles have also not been reported in the literature yet.…”