Making of Error Free Nanostructure using Protein “Rebar” which is better than DNA Origami

Strands of DNA can fit together like Lego blocks to make nanoscale objects of complex shape and structure. So DNA is also the stuff of nanotechnology. To realize a key goal: building durable miniature devices such as biosensors and drug-delivery containers, researchers need to work with much larger collections of DNA which is been difficult because Floppiness of long chains of DNA  and the standard method of assembling long chains is prone to error.

RecA, the DNA binding proteins are useful as a kind reinforcing bar, to support the floppy DNA scaffolding by constructing several of the largest rectangular, linear and other shapes which have ever assembled from DNA by the researchers of the National Institute of Standards and Technology (NIST) .these are two to three times larger than those built using standard DNA self-assembly techniques. Reduction of the number of errors in constructing the shapes is required by using fewer chemically distinct pieces to build organized structures which are known as DNA origami.

The NIST scientists integrated filaments of RecA into the assembly of DNA structures. The advantage is it automatically attracts other units to line up alongside it if Once one unit of the protein binds to a small segment of double-stranded DNA. RecA stretches, widens and strengthens the DNA strands for which 2-nanometer-wide strand of DNA can transform into a rigid structure more than four times as wide. The RecA method greatly extends the ability of DNA self-assembly methods to build larger and more sophisticated structures.

In DNA origami, short strands of DNA with particular sequence of four base pairs are used as staples to tie together in long sections of DNA. By quickly using up the long string, the strand may loop back on itself to make the skinny DNA skeleton stronger and thicker. The new method goes beyond the DNA origami techniques. The skinny piece of single-stranded DNA lies in between the location of the short, single-stranded pieces of DNA that act as staples mark. A section of the long piece of single-stranded DNA into the double-stranded version of the molecule is transformed by the enzyme DNA polymerase.

RecA assembles all along the double strand and limiting the need for extra staples to maintain its shape. RecA method is likely able to build organized structures with fewer errors than DNA origami with the use of fewer staple.

NEXT WAVE PHOTODETECTOR USING GRAPHENE

To develop a new type of photodetector, Researchers from UCLA are using graphene which has superior sensing and imaging capabilities and is able to work with several different types of light. Due to the ability to absorb energy from a broad swath of the electromagnetic spectrum Graphene is able to detect photons —from ultraviolet light to visible light to the infrared and microwave bands.
The researchers placed strips of graphene to create the improved photodetector over a silicon dioxide layer, which covers a base of silicon. They then created a series of comb-like nanoscale patterns comprised of gold with about 100 nanometer wide teeth. The graphene can catch the incoming photons and convert them into an electrical signal. The gold comb-shaped nanopatterns transfer the information into a processor and the processor even under low-light conditions produces a comparably high-quality image.
As per emih Cakmakyapan, a UCLA postdoctoral scholar and the lead author of the study,“This design efficiently produces an electrical signal which follows ultrafast and subtle variations in the light's intensity over the entire spectral range, from visible to infrared.”In different imaging devices, Different photodetectors sense different parts of the light spectrum and create images from the patterns. To sense thermal radiation invisible to the naked eye at night, Photodetectors can be used or in cameras that can identify chemicals in the environment by how they reflect light.
Depending on their operating speed, their sensitivity to lower levels of light and how much of the spectrum they can sense.

The photodetectors can sense different types of light largely which It has proven difficult for engineers to improve a photodetector’s capability in one specific area without diminishing at least one of the other two areas.
The new and improved photodetector represents an improvement in all three areas as it operates across a broad range of light, processes images more quickly and is more sensitive to low levels of light than current photodetectors. Our photodetector could extend the potential uses of photodetectors in imaging and sensing systems,” Mona Jarrahi, a professor of electrical and computer engineering, who led the study, said in a statement. “It could be used in environmental sensing technologies to more accurately identify the concentration of pollutants.”It could also dramatically improve thermal imaging in night vision or in medical diagnosis applications where precise differences in temperatures can give doctors a lot of information on their patients.