Polyelectrolytes based biomimetic interfaces for bioelectronic applications.

摘要

Biomimetic interfaces consisting of polyelectrolyte multilayers, lipid bilayers, proteins and other nanostructured components have been fabricated and characterized in this study. While each chapter addresses a unique architecture or issue, the underlying theme of the study is the development of nanostructured biomimetic architectures that express protein activities and can be used to produce high-value devices and processes. Neuropathy target esterase (NTE) is a membrane protein found in human neurons. Binding of certain organophosphorus (OP) compounds to NTE is believed to cause OP-induced delayed neuropathy (OPIDN), a type of paralysis for which there is no effective treatment. Mutations in NTE have also been linked with serious neurological diseases, such as Lou Gehrig's disease. In the first part of this dissertation, a nanostructured biosensor to rapidly and sensitively measure the esterase activity of a fragment of NTE known as NEST is presented. The biosensor was fabricated by co-immobilizing two enzymes tyrosinase and NEST. The biosensor gives dose-dependent decrease in sensor output in response to known NEST (or NTE) inhibitors. The second part of this dissertation presents a theoretical model for bi-enzyme electrode biosensors that use substrate recycling to increase sensitivity. The model was validated using a rotating disk electrode on which tyrosinase and NEST were co-immobilized. The model's predictions were then used to quantify the effects of mass transport, partition coefficients, and enzyme kinetics on the biosensor's metrological properties. This approach can be used to optimize the performance of bi-enzyme electrodes that involve substrate recycling. The third part of this study presents novel methods to produce arrays of bilayer lipid membranes (BLMs) on patterned polyelectrolyte multilayers. Liposomes composed of 1, 2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1, 2-dioleoyl-sn-glycero-3-phosphate (DOPA) were found to adsorb preferentially on poly (dimethyldiallylammonium chloride) (PDAC) and poly(allylamine hydrochloride) (PAH) surfaces, and in much smaller amounts onto sulfonated poly(styrene) (SPS) surfaces. Poly(ethylene glycol) (m-dPEG acid) coated surfaces were found to resist liposome adsorption. These results allowed the fabrication of BLM microarrays by exposing substrates patterned with PDAC, PAH and m-dPEG to DOPA/DOPC vesicles. The fourth part of this study presents a novel biomimetic interface consisting of an electrolessly deposited gold film overlaid with a tethered BLM (tBLM). Two model membrane biomolecules, the ionophore valinomycin and NEST, were incorporated into the tBLM, and the activity of the resulting biomimetic interfaces was measured. Microcontact printing (muCP) of electrolessly deposited gold patterns on glass slides was also used to generate arrays of tBLMs. Such arrays may be useful for high-throughput screening of drugs and chemicals that interact with cell membranes. The fifth part of this study presents an approach to fabricate high-quality, 3D patterned bionanocomposite layered films on substrates whose surface properties are incompatible with existing self-assembly methods. The last part of this study presents an approach that can be used to create stable, nanostructured, amphiphilic and cross-linkable PAMAMOS-DMOMS dendrimer patterns.