In recent years, there is a growing interest in developing metal based antimicrobial nanomaterials suitable for agricultural and biomedical applications. For centuries, Copper (Cu) biocide has been used for protecting a wide variety of crops from devastating bacterial and fungal diseases. However, prolonged and aggressive use of Cu led to the development of resistance and accumulation in soil. The latter has been linked to aquatic toxicity due to soil Cu leaching. Furthermore, copper build up in soil causes phytotoxicity and reduces uptake of micronutrient Zn through the root system. In biomedical field, Cu has been historically used as an antimicrobial agent in wound dressing. In healthcare facilities, Cu based touch surfaces are shown to significantly reduce antimicrobial infection rates. Emerging biomedical applications include wound healing, sensing and even potential use of nano-Cu as cancer therapeutic. However, Cu cytotoxicity is a serious concern. There is a strong need for developing advanced Cu based composite material that will retain antimicrobial properties as reduced Cu load until a suitable alternative becomes available. In this thesis, the objective is to develop a Cu coated Iron Oxide nanocomposite. The idea is to distribute Cu over the high surface area of biocompatible Iron Oxide nanoparticle (IONP) to improve Cu bioavailability. In the design of Cu-IONP nanocomposite, we have introduced N-Acetyl Cysteine (NAC, an antioxidant biomolecule) that anchors IONP to Cu. The composite was synthesized using a co-precipitation technique. Characterization of the Cu/NAC-IONP nanocomposite was done using Atomic Absorption Spectroscopy (AAS), Dynamic Light Scattering, Fourier Transform Infrared Spectroscopy (FTIR), Scanning electron microscopy and X-Ray Photoelectron Spectroscopy. Characterization results support the formation of composite and NAC as a bidentate ligand conjugating Cu to IONP. Antimicrobial activity of Cu/NAC-IONP nanocomposite was studied using ASTM published protocol. The Cu/NAC-IONP nanocomposite shows higher Colony Forming Unit Percent reduction when compared with NAC-Iron Oxide and no treatment. This suggests that antimicrobial activity of Cu is retained in the nanocomposite. Additionally, AAS study revealed an interesting property of the nanocomposite that the Cu release is strongly dependent on incubation temperature. Cu ion release is increased with the increase in incubation temperature. This new finding may lead to design of a delivery system where Cu release can be controlled by tuning temperature.
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Master of Science (M.S.)
College of Medicine
Length of Campus-only Access
Masters Thesis (Open Access)
Belnour, Danya, "Copper/N-acetylcysteine Coated Iron Oxide Nanoparticles Synthesis, Characterization, and Antimicrobial Activities" (2020). Electronic Theses and Dissertations, 2020-. 174.