Biomolecular metallization

In this chapter we describe the basic principles involved in the controlled production and modification of two-dimensional protein crystals. These are synthesized in nature as the outermost cell surface layer (S-layer) of prokaryotic organisms and have been successfully applied as basic building blocks in a biomolecular construction kit. Most importantly, the constituent subunits of the S-layer lattices have the capability to recrystallize into iso-porous closed monolayers in suspension, at liquid-surface interfaces, on lipid films, on liposomes, and on solid supports (e.g., silicon wafers, metals, and polymers). The self-assembled monomolecular lattices have been utilized for the immobilization of functional biomolecules in an ordered fashion and for their controlled confinement in defined areas of nanometer dimension. Thus, S-layers fulfill key requirements for the development of new supramolecular materials and enable the design of a broad spectrum of nanoscale devices, as required in molecular nanotechnology, nanobiotechnology, and biomimetics [1-3]. 

Particularly attractive for numerous bioanalytical applications are colloidal metal (e.g., gold) and semiconductor quantum dot nanoparticles. The conductivity and catalytic properties of such systems have been employed for developing electrochemical gas sensors, electrochemical sensors based on molecular- or polymer-functionalized nanoparticle sensing interfaces, and for the construction of different biosensors including enzyme-based electrodes, immunosensors, and DNA sensors. Advances in the application of molecular and biomolecular functionalized metal, semiconductor, and magnetic particles for electroanalytical and bio-electroanalytical applications have been reviewed by Katz et al. [142]. 

Asthagiri, D. Pratt, L. R. Paulaitis, M. E. Rempe, S. B., Hydration structure and free energy of biomolecularly specific aqueous dications, including Zn2+ and first transition row metals, J. Am. Chem. Soc. 2004,126, 1285-1289... 

Biomolecular spectroscopy on frozen samples at cryogenic temperatures has the distinct disadvantage that the biomolecules are in a state that is not particularly physiological. Recall that EPR spectroscopy is done at low temperatures to sharpen-up spectra by slowing down relaxation, to increase amplitude by increasing Boltzmann population differences, and to decrease diamagnetic absorption of microwaves by changing from water to ice. Certain S = 1/2 systems, notably radicals and a few mononuclear metal ions, have sufficiently slow relaxation, and sufficiently limited spectral anisotropy to allow their EPR detection in the liquid phase at ambient temperatures, be it in aqueous samples of reduced size. 

P. Estrela, P. Migliorato, H. Takiguchi, H. Fukushima, and S. Nebashi, Electrical detection of biomolecular interactions with metal-insulator-semiconductor diodes. Biosens. Bioelectron. 20, 1580-1586 (2005). 

The hydrogenase may be electrically wired with different semiconductors, metals and conducting materials as an electrode. This property of the enzyme is successfully used in design of different biomolecular device for renewable energy production and conversion systems based on molecular hydrogen as intermediate energy carrier. In many cases... 

Biomolecular electronics (BME), 13 553 Biomolecules, metal-containing, 24 47 Bio-oils, 3 699-701 uses of, 3 701... 

Ruiz-Taylor, L.A., Martin, T.L., Zaugg, F.G., Indermuhle, R, Nock, S., and Wagner, R, Monolayers of derivatized poly(L-lysine)-grafted poly(ethylene glycol) on metal oxides as a class of biomolecular interfaces, Proc. Natl. Acad. Sci. USA, 98, 852-857, 2001. 

SF (chiral) spectroscopy can be easily modihed for vibrational spectroscopy as shown in Figure 10.16b. This SF vibrational spectroscopy can beneht from plas-mon resonances of a metallic tip by tuning the input beam frequency and/or the output frequency tUspo- Therefore, spatial resolution of SF vibrational spectroscopy could reach to the order of several nanometers. Development of tip-enhanced SF chiral/vibrational spectroscopy is awaited for biomolecular imaging. 

The fabrication of regular arrays of metallic nanoparticles by molecular templating is of great interest in order to prepare nanometre structures for future use in nanoelectronics, optical and chemical devices.43 A sensitive, rapid and powerful direct analytical method is required for the quantitative analysis of high purity platinum or palladium nanoclusters produced by biomolecular... 

Biological samples are potentially excellent records of their environment and are being examined by inorganic and biomolecular mass spectrometry to an increasing extent. Biomaterials such as carbonate shells, fish otoliths and fish scales or tree rings that increase their mass regularly on an annual basis may record changes in their environment via the concentrations of metals or non-metals and the isotopic composition of elements.2... 

With respect to sample preparation, it is necessary to develop effective and fast procedures involving only a few steps in order to avoid contamination, reduce analysis time and to improve the quality of analytical work. Microsampling and the use of smaller sample sizes is required and also the further development of analytical techniques. In particular, there is a need for the development of online and/or hyphenated techniques in ICP-MS. Microsampling combined with the separation of small amounts of analytes will be relevant for several chromatographic techniques (such as the development of micro- and nano-HPLC). There is a demand for further development of the combination of LA-ICP-MS as an element analytical technique with a biomolecular mass spectrometric technique such as MALDI- or ESI-MS for molecular identification and quantification of protein phosphorylation as well as of metal concentrations, this also enables the study of post-translational modifications of proteins, e.g. phosphorylation. 

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