Engineered nanoparticles have unique physiochemical properties and are used in a variety of applications including as cosmetics, pharmaceuticals, and catalysts. Nanoparticles can make their way into the environment and can interact with biological systems. Therefore it is important to understand how nanoparticles behave in different biological and environmental media. In this study, we have investigated two aspects: (1) surface chemistry of titanium dioxide nanoparticles in different biological and environmental media of different pH with ATR-FTIR spectroscopy and (2) dissolution behavior of nanoparticles (NPs), including ZnO and CuO, in biological and environmental media at different pH. In particular, in situ measurements of changes in surface charge and surface functionality were made. Surface adsorption of different biological and environmental components from these media on TiO<sub>2</sub> NPs at varying pH was monitored with attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The biological and environmental media investigated included Roswell Park Memorial Institute medium commonly referred to RPMI With/ Without FBS (fetal bovine serum), Moderately Hard Reconstituted Water (MHRW), simulated lung fluids (Artificial Lysosomal Fluids (ALF) and Gamble’s solutions) and gastric fluids. Overall, this study provides insights and a better understanding of nanomaterials in different biological and environmental media. Additionally, copper oxide and zinc oxide nanoparticles, ca. 24 nm in diameter, have been placed in several different simulated biological fluids in order to investigate their dissolution behavior in the presence and absence of adsorbed organic matter and proteins. In particular, after coating the nanoparticles surface with either bovine serum albumin (BSA), immunoglobulin (IgG) and humic acid (HA), these nanoparticles were placed in simulated biological fluids representative of lung fluids such as artificial lysosomal fluids (ALF) and artificial interstitial fluid (Gamble’s solutions). Here, we show that Cu<sup>+2</sup> ions were elevated when BSA was adsorbed on the surface in ALF compared to when both, HA and IgG, were adsorbed on the nanoparticle surface. CuO NPs undergo significant dissolutions in media over time scales because of ligand-assisted ion release. BSA adsorption promotes the dissolution of CuO nanoparticles through formation of surface complexes that kinetically enhance the dissolution whereas the HA and IgG do not.

Surface chemistry of engineered nanoparticles in biological and environmental media of varying pH

255th National Meeting (2018)

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