Biomolecular nanostructures

Debra Rolison (right) was born in Sioux City, Iowa in 1954. She received a B.S. in Chemistry from Florida Atlantic University in 1975 and a Ph.D. in Chemistry from the University of North Carolina at Chapel Hill in 1980 under the direction of Prof. Royce W. Murray. She joined the Naval Research Laboratory as a research chemist in 1980 and currently heads the Advanced Electrochemical Materials section. She is also an Adjunct Professor of Chemistry at the University of Utah. Her research at the NRL focuses on multifunctional nanoarchitectures, with special emphasis on new nanostructured materials for catalytic chemistries, energy storage and conversion, biomolecular composites, porous magnets, and sensors. 

Albeit the substantial progress in the bioelectrochemical activation of enzymes, one could identify two important future challenges in the field (i) The active relay units wiring the redox centers of the enzymes with the electrodes could be generated by photoinduced electron transfer. This could pave the way to the photochemical wiring of enzymes and to the development of photobiofuel cells, (ii) DNA scaffolds provide unique templates for the ordered self-assembly of molecular or biomolecular units through dictated hybridization. The ordering of relay units and enzymes, or of relay units photosystems, on DNA templates associated with electrodes may yield attractive new supramolecular nanostructures for bioelectronics and optobioelec tronic s. 

Four different aryldiazonium salts have been used to functionalize SWCNTs through electrochemical reduction. By XPS and Raman diffusion measurements, the growth of aryl chains on the sidewalls of the nanotubes was observed [178]. Electrically addressable biomolecular functionalization of SWCNT electrodes and vertically aligned carbon nanofiber electrodes with DNA was achieved by elec-trochemically addressing (reduction) of nitrophenyl substituted nanotubes and nanofibers. Subsequently, the resulting amino functions were covalently linked to DNA forming an array of DNA-CNT hybrid nanostructures (Scheme 1.28) [179],... 

In this study, we report a very effective and widely applicable method for fabricating of nanostructures of an inert material for the biomolecular nanoarrays. The stable nanostructures of the PEG and PVA hydrogels were directly fabricated on gold substrates by UV-NIL (Fig. la). The site-selective nanoarray of various biomolecules such as protein and tethered lipid bilayer raft membrane (tLBRM) was constructed from a nanoimprinted inert materials by stepwise molecular self-assembly (Fig. lb and Ic). 

The detection of DNA hybridization using electrochemical readout is particularly attractive for the development of clinical diagnostics. The use of nanostructured materials in electrical detection for biomolecular sensing offers unique opportunities for electrochemical transduction of DNA sensing events. Tian and co-workers [175] have reported that PANI/Gold nanoparticle multilayer films electrocatalyze the oxidation of nicotinamide adenine dinucleotide (NADH) and detect DNA hybridization by both an electrochemical method and by surface plasmon enhanced fluorescence... 

It is known that more highly conducting nanodomains exist within the essentially amorphous ICP host structure and that electrochemical switching speeds can be extremely rapid in nanowires composed of these materials. It is also known that control of nanotopography in other biomaterials can have a profound effect on the adhesion of mammalian cells. Given the explosion of activity in the area of ICP nanostructures, there is no doubt that these enhanced properties should translate into more effective biomolecular sensors and actuators. 

On a molecular scale, the accurate and controlled application of inter-molecular forces can lead to new and previously unachievable nanostructures. This is why molecular self-assembly (MSA) is a highly topical and promising field of research in nanotechnology today. With many complex examples all around in nature, MSA is a widely perceived phenomenon that has yet to be completely understood. Biomolecular assemblies are sophisticated and often hard to isolate, making systematic and progressive analyzes of their fundamental science very difficult. What in fact are needed are simpler MSAs, the constituent molecules of which can be readily synthesized by chemists. These molecules would self-assemble into simpler constmcts that can be easily assessed with current experimental techniques [37, 38]. 

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