Interactions of Nanoparticles and Polycations with Bacterial Cell Surface Structures PDF Download

Author: Emily Rose Caudill
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Languages : en
Pages : 0

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Book Description
Materials with features on the nanoscale date back hundreds of years, yet humans' ability to manipulate and control chemical systems on the atomistic level has grown immensely, particularly over the last 50 years. With expanded research capabilities, the use of nanotechnology in commercial products is also increasing, from quantum dots in television screens to novel battery materials for electric vehicles. However, along with commercialization, the risk of inadvertent release of these materials into the environment arises as well. Ecologically vital biological systems in the environment are subsequently suspectable to interaction with nanomaterials which could potentially result in harm. There are a number of complex factors associated with studying the interface between nanoparticles and cells, including nanoparticle core material, size, shape, functionalization, and transformation of the material during environmental exposure, as well as biological cell type, size, shape, and cell surface composition. As the cell membrane is likely to be the first point of contact between a cell and nanomaterial, the bacterial cell surface was modeled using phospholipids and other surface components from Gram-positive and Gram-negative bacteria. We investigated (1) cationic polymer interaction with supported lipid bilayers, as nanoparticles are often functionalized with analogous positively charged chemical groups, (2) branched polyethylenimine functionalized nanoparticle interaction with peptidoglycan and wall teichoic acids of strains of Gram-positive bacteria that differ in their wall teichoic acid composition, and (3) positively charged nanoparticle interaction with lipopolysaccharide (LPS)-containing supported lipid bilayers containing either smooth or rough LPS molecules from Escherichia coli. Using techniques sensitive to membrane surface adsorption, including quartz crystal microbalance with dissipation monitoring (QCM-D) and solid-state nuclear magnetic resonance (NMR) spectroscopy, our results demonstrate interactions between nanoparticles and cell surface structures depend on factors including electrostatic interactions, cell surface rigidity, as well as specific chemical groups present on the polycations, nanoparticles, and cell surface components. In studying the nano-bio interface on the molecular-level, the underlying goal of this research is to maintain benefit from the unique properties of nanomaterials, while reducing inadvertent negative consequences to biological systems.