Chiral plasmonic nanostructures

Chiral plasmonic DNA nanostructures with switchable circular

Switching the CD signal

For the CD measurements, the nanohelix-covered quartz glass is placed perpendicular to the measurement light beam inside a buffer-filled cuvette. The nanohelices standing upright on the substrate are hence aligned parallel to the beam (Fig. 2). Owing to the flexibility of the linkers and the roughness of the protein substrate, we did not expect to achieve perfect alignment, that is, all helices standing exactly perpendicular to the surface. Nonetheless, we observed a dominant plasmonic CD signal of left-handed helices when the circularly polarized light passes through the samples along the helical axis (CD). Instead of the peak-dip (bisignate) CD of the L-NHs isotropically dispersed in solution (Fig. 2a), an inverted dip-peak spectrum with a dominant peak at the plasmon resonance is expected from theory (Fig. 2b, see Supplementary Fig. S1 and Supplementary Table S1 for other geometries) and becomes apparent in the experiment at 528±4 nm (Fig. 2c). In the next step the quartz glass was dried with nitrogen and placed again into the emptied cuvette.Surface-bound chiral plasmonic nanostructure. resulted in the alignment of the L-NHs parallel to the glass surface and therefore perpendicular to the light beam. As expected, the recorded CD spectrum shows a peak-dip signal with a dominant dip at 552±4 nm (CDxy). The CDxy spectrum is flipped along the horizontal axis and slightly red shifted (24±8 nm) compared with the CD. The wavelength shift between CDxy and CD agrees with the calculations for nanohelices in a uniform media.CD splitting theory and comparison to experimental results. extent (see Supplementary Fig. S2). To show the reversibility of the CD switching, the cuvette is filled again with buffer and a new CD spectrum is recorded. Judging from the recovered CD signal, it can be concluded that the L-NHs stand up again and align parallel to the light beam, although some of the helices or individual nanoparticles may have been washed away and some helices may have stuck permanently to the substrate during the flushing and drying process, respectively (see also Supplementary Fig. S3). Another drying step switches the orientation and the CD signal once more. It is hence possible to reversibly switch between two alignment states and subsequently gather the signals of CD and CDxy without changing the orientation of the substrate (see Supplementary Fig. S4 for switching CD spectra of right-handed nanohelices and Supplementary Fig. S5 for switching CD spectra of L-NHs assembled on the surface).

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CRC Press Characterization of Nanostructures
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Paper battery?

by edsdesk

Mon Dec 7, 4:28 pm ET
WASHINGTON (Reuters) – Ordinary paper could one day be used as a lightweight battery to power the devices that are now enabling the printed word to be eclipsed by e-mail, e-books and online news.
Scientists at Stanford University in California reported on Monday they have successfully turned paper coated with ink made of silver and carbon nanomaterials into a "paper battery" that holds promise for new types of lightweight, high-performance energy storage.
The same feature that helps ink adhere to paper allows it to hold onto the single-walled carbon nanotubes and silver nanowire films

Some ... some not.

by setArcos

Biotechnology, bioinformatics
Emerging technology
Genetic engineering
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Artificial photosynthesis
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Body implants, prosthesis
In vitro meat
Regenerative medicine
[edit] Energy systems
Emerging technology
Concentrated solar power includes thermal

Nanotubes Increase Solar PV Conductivity 100 Million-Fold  — Sourceable
Carbon-based nanostructures are already being used as materials in solar cells with increasing frequency, yet their ability to enhance electrical performance has thus far been hampered by limited ability to assemble orderly networks using the materials.

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