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Results for “Redox-Active Enzymes”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS2009

Selective functionalization of carbon nanotube tips allowing fabrication of new classes of nanoscale sensing and manipulation tools

Embodiments in accordance with the present invention relate to techniques for the growth and attachment of single wall carbon nanotubes (SWNT), facilitating their use as robust and well-characterized tools for AFM imaging and other applications. In accordance with one embodiment, SWNTs attached to an AFM tip can function as a structural scaffold for nanoscale device fabrication on a scanning probe. Such a probe can trigger, with nanometer precision, specific biochemical reactions or conformational changes in biological systems. The consequences of such triggering can be observed in real time by single-molecule fluorescence, electrical, and/or AFM sensing. Specific embodiments in accordance with the present invention utilize sensing and manipulation of individual molecules with carbon nanotubes, coupled with single-molecule fluorescence imaging, to allow observation of spectroscopic signals in response to mechanically induced molecular changes. Biological macromolecules such as proteins or DNA can be attached to nanotubes to create highly specific single-molecule probes for investigations of intermolecular dynamics, for assembling hybrid biological and nanoscale materials, or for developing molecular electronics. In one example, electrical wiring of single redox enzymes to carbon nanotube scanning probes allows observation and electrochemical control over single enzymatic reactions by monitoring fluorescence from a redox-active cofactor or the formation of fluorescent products. Enzymes ''nanowired'' to the tips of carbon nanotubes in accordance with embodiments of the present invention, may enable extremely sensitive probing of biological stimulus-response with high spatial resolution, including product-induced signal transduction.

Wade, Lawrence A.↗
NASA NTRSDate not supplied

Electrochemical Life Detection Methods for Ocean World Exploration

Ubiquitous across terrestrial life is cellular machinery that allows chemical energy flow by facilitating and regulating electron-transfer and chemical modification pathways. Key classes of energy transport molecules enable this movement of electrons for a variety of biological purposes. Additionally, biological enzymes function to add or remove functional groups such asphosphate moieties to redox biomolecules. Presumably, extraterrestrial life is likely to rely on similar energy transport mechanisms. With the search for life in our solar system focused on the icy satellites of Jupiter and Saturn, Europa and Enceladus, developing instrumentation capable of measuring electrochemical redox signatures representative of biomolecules or enzymatic activity in seawater appears a promising and novel means of life detection. Here, we report our adaptation of the Mars Phoenix Wet Chemistry Laboratory (WCL) electroanalytical voltammetry capabilities to assay life-critical redox molecules in synthetic seawater representative of a saline alkaline solution similar to what has been predicted from the Cassini mission data of Enceladus’ sub-surface ocean. In addition, we employ a well-established electrochemical assay that indicates phosphatase activity by comparing substrate and product redox signatures. Our study demonstrated a 10 nM limit of detection for biological redox molecules and a 3 aM limit of detection for alkaline phosphatase in seawater. Incorporation of these methods into next generation WCL payloads aimed at ocean world life detection will enable the search for biological redox-active species and enzymatic activity as indicators of life.

planetary instruments↗