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Reciprocal Redox of Biomolecules on Metal Oxide Nanomaterial Surfaces

出版	ProQuest LLC, 2023
URL	http://books.google.com.hk/books?id=aE2-0AEACAAJ&hl=&source=gbs_api

註釋Fundamentally understanding the mechanism of interaction between engineered metal oxide nanomaterials and biomolecules is essential for assessing their larger impact on the environment. With the growing use of these nanomaterials for various energy storage applications and the lack of proper recycling, the potential for environmental harm is high. LiCoO2 nanomaterials, specifically, have the potential to not only release Co ions into aqueous environments, but also have the potential to do redox chemistry with surrounding biomolecules. This behavior has been seen with LiCoO2 interacting with nicotinamide adenine dinucleotide (NADH) causing an influx of released Co and oxidation of NADH to NAD+. Herein we propose a unifying mechanism for how biomolecules interact with the surfaces of and undergo redox transformations with high-valent metal oxide nanomaterials. Using a suite of analysis techniques, we detected that redox of NADH and other biomolecules relied on the presence of phosphate functional groups directly attached to the molecule to initiate binding to the nanomaterial. We showed that the coupling of this functionality and redox capability both increased the amount of Co released from the nanomaterial as well as the oxidation of the biomolecules. We sought to generalize this mechanism to other metal oxides as well as other biomolecules and discovered that other high-valent metal oxides, such as Mn2O3, also interact with NADH in a similar manner to LiCoO2. Additionally, we wanted to generalize the mechanism to other PO4-containing biomolecules. For example, DNA contains phosphate groups and has exhibited oxidative damage when cells are exposed to high-valent metal oxides. We studied the interaction between DNA and a model peptide equivalent (PNA) on the surfaces of LiCoO2 nanomaterials and confirmed that phosphate functionality increases the binding on the molecule to the surface and potentially allows for oxidative damage to the DNA molecules. Other PO4 containing biomolecules were also confirmed to interact with Co materials more than their counterparts without the functionality. A component of nanomaterial transformations in aqueous media that is often overlooked is the complexity of said media. If we want to understand adverse interactions between biomolecules and nanomaterials in more realistic environments, it is imperative to investigate how the components of the media potentially interfere or enhance the interaction. We studied the LiCoO2-NADH interaction in various environments which systematically looked at the role of the buffer and pH, and the role of the carbon sources present in model bacterial growth medium. In this study, we deduced that pH as well as the presence of a carbon source, regardless of concentration, are key factors in how the redox reaction proceeds. By understanding how the NADH-LiCoO2 reaction changes under different environments, we created a larger picture of how these reactions can take place under 'real-life' conditions and therefore have a better understanding of the impact that these high-valence metal oxides have on the biological organisms that they encounter upon accidental release into the environment.