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

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.

Synthetic copolymer conjugates of docetaxel and in vitro assessment of anticancer efficacy

Docetaxel (DTX) is a widely used chemotherapy drug that is associated with numerous side effects and limited bioavailability. We show synthetic copolymer conjugates of docetaxel with drug loading up to 20% and assess their efficacy in MCF-7 cells.

Study on Low Temperature Stripping Material Based on the Modified Acrylate Polymer

With the method of solution polymerization, we prepared a high conversion rate and larger molecular weight acrylate copolymer. Using synthetic copolymer, low temperature stripping material was compounded with the proportional certain kinds of crosslinking agent, plasticizer, thickener and release agent, according to the certain reaction temperature and the loading sequence. The material mechanical properties, stripping, decontamination rate was tested and characterization. We got the strip materials meeting the low temperature environment. Finally, the influence factors of copolymerization reaction: the choice of solvent, dosage of initiator, monomer and the dosage was discussed. To achieve higher conversion rate and larger molecular weight acrylate copolymer, the method of solution polymerization was adopted in this study. Low temperature stripping material was compounded with synthetic copolymer, together with crosslinking agent, plasticizer, thickener and release agent in certain proportion, according to reaction temperature and the loading sequence. This material’s mechanical properties, stripping, decontamination rate were tested and characterizing definition was done. Results showed this strip material could meet the requirement of low temperature environment. Finally, the influence factors of copolymerization reaction were discussed, including the choice of solvent, dosage of initiator, monomer and the dosage.

Syntheses and Evaluation of Copolymer 6-Aminohexanoic Acid and 4R-Hydroxy-L-Proline for Bone Repair

A novel synthetic copolymer (PAA) for bone repair was prepared by melt condensation polymerization with 6-aminohexanoic acid (He) and 4R-hydroxy-L-proline (Hyp). The structure and thermal property were characterized by infrared spectrometer (IR), nuclear magnetic resonance (H1NMR) and differential scanning calorimeter (DSC). The results indicated that the PAA had amide linkages in their polymer chains. The Tg of PAA was 57.56°C and significantly higher than that of nylon6, 50.46°C. Meanwhile, the intrinsic viscosity and mechanical properties were investigated at different He/Hyp ratios. It revealed that appropriate introduction of Hyp group could control the degree of polycondensation and adjusted mechanical properties of PAA obviously close to natural bone. The prepared polymers had about 2.12~18.21 % weight loss after 8-week soaking in PBS, showed degradable properties which was essentials to new bone growth. The copolymer of He and Hyp with ratios of 90/10 had 6.57 % weight loss and maintained the yield compressive strengths with about 67.51 MPa after 8 weeks, which exhibited a compatible mechanical properties and degradation speed for bone repair.