1.Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA, 92182-1030, USA ;2.Faculty of Production Engineering Badgasteiner Str. 1, University of Bremen, 28359, Bremen, Germany ;3.Leibniz Institute for Materials Engineering IWT, Badgasteiner Str. 3, 28359, Bremen, Germany ;4.Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ, 85287-1604, USA ;5.Center for Micro-Engineered Materials, Advanced Materials Laboratory, University of New Mexico, 1001 University Blvd SE, Suite 103, Albuquerque, NM, 87106, USA ;6.Department of Chemical and Biological Engineering, University of New Mexico, 210 University Blvd NE, Albuquerque, NM, 87131-0001, USA ;
Abstract:
Fumed silica nanoparticles (FSN) are one of the most common synthetic forms of silica, but prolonged exposure leads to cell toxicity and apoptosis due to reactive oxygen species (ROS) generation and cell membrane perturbation resulting from hydrogen bonding and electrostatic interactions. Increasing attention is being put on synthesizing FSN material that is safer both for workers involved in large-scale industrial production, and consumers coming in contact with FSN additives. In the present work, we explore the molecular structural differences and efficacy of Al- and Ti-metal-doped FSN which has previously been shown to reduce toxicity effects of FSN. We use a combination of 29Si and 27Al solid-state magic angle spinning (MAS) NMR, Raman spectroscopy, and thermogravimetric analysis (TGA) to probe the surface and bulk structure and quantify the adsorption capacity and reactivity of the metal-doped FSN with respect to amino acid thermal condensation. Alanine was selected as the amino acid of choice for its simplicity and ubiquity in biochemical reactions. The results indicate that metal doping has a modest impact on the fumed silica molecular structure with a small decrease in amino acid adsorption capacity and thermal condensation reactivity as a function of increased metal doping.