DNA origami proposes the way to a multipurpose biosensory

“Our work provides proof of a concept that shows the way to a one-step method that could be used to identify and measure nucleic acids and proteins,” says Paul Rothemund (BS ’94), a guest associate at Caltech in calculating and mathematical sciences, Calculation and neural systems.

The work that describes the work recently appeared in the magazine Proceedings of the National Academy of Sciences. The main authors of the work are the former post-dotland scholar Caltech Byin Jeon and the current graduate student Matteo M. Gureschi, who completed his job at the Rothemund lab.

In 2006, Rothemund published his first work on the DNA Origami, a technique that provides a simple but excellent control over the design of molecular structures on nannuable using nothing more than DNA.

Basically DNA origami allows long DNA series to transplant into any desired shape through self-slicing. (In 2006, Rothemund celebrated the technique to create miniature DNA smiles on measuring 100 nanometers over and 2 nanometer thickness). Researchers start with a long series of DNA, scaffolding, in solution. Because the nucleotide base that make up the bottom of the binding in a famous way (Adenin binds to thymine and Gvanin binds to cytosine), scientists can add hundreds of short complementary DNA sequences, knowing that they will be tied to any end in the famous places. These short, added pieces of DNA folded the scaffolding and gave it a shape, acting as “staples” that keep the structure together. The technique can then be used to create shapes in the range from the North and South America map to the transistor transistor.

In the new work of Rothemund and his colleagues, they used DNA Origami to create a structure similar to Lilypadu-Ravno, a circular surface of about 100 nanometers in diameter, related to DNA midfielder to the Golden Electrode. Both Lilypad and electrodes have a short DNA at the disposal of a tie with an analysis, a molecule of interest to the solution – whether it is a molecule of DNA, protein or antibodies. When analytics binds to these short strands, Lilypad descends to the golden surface, bringing 70 reporters molecules to Lilypad (indicating that the target molecule is present) in contact with the golden surface. These journalists are a regular reactive molecule, which means they can easily lose electrons during reaction. So, when electrodes approach enough, electric current can be observed. The stronger current indicates that more molecules are present in interest.

Previously, a similar approach to the production of the biosensor was developed by one of a series of bottoms, not the structures of the origami DNA. This earlier work was conducted by Kevin W. Plaxco (doctorate ’94) from UC Santa Barbara, who is also the author of the current work.

Caltech’s Guareschi points out that the new Lilypad origami is large compared to one DNA strap. “This means that it can fit 70 journalists on one molecule and keep them away from the surface before binding. Then when the analytus is tied and Lilypad reaches the electrode, there is a large gain of signals, which facilitates the detection of the change.” Guareschi says.

The relatively large size of Lilypad origami also means that the system can easily accommodate and detect larger molecules, such as large proteins. In the new work, the team showed that two short series of DNA on Lilypad and the golden surface can be used as adapters, making it a protein sensor rather than DNA. In the paper, researchers added vitamin biotin to these short DNA strings to turn the system into a stroptavidine protein sensor. Then they added Aptamer DNA, DNA DNA that can be tied to a specific protein; In this case, they used APTAMERS, which is bound to a protein called growth factor with thrombocyte BB (PDGF-BB), which could be used to diagnose diseases such as cirrhosis and inflammatory bowel disease.

“We just add these simple molecules to the system and it’s ready to feel something different,” Guareschi says. “It is big enough to receive everything you throw – it could be suitable, nano -mosque, antibodies fragments – and should not be completely redesigned every time.”

Researchers also show that the sensor can be reused several times, and the new adapters have been added to each circle for different detection. Although performance is gently degraded over time, the current system could be reused at least four times.

In the future, the team hopes that the system could also be useful for proteomics – studies that determine what proteins are in the sample and in which concentration. “You could have more sensors at the same time with different analyts, then you could make, switch an analyte and a point again. And you could do that several times,” Guareschi says. “Within a few hours you can measure hundreds of proteins using one system.”

Additional work authors, “electrochemical detection of DNA and protein modular DNA Origami”, were Jaimie M. Stewart from UCLA; Emily Wu and Ashwin Gopinath of MIT, Netzahualcóyotl Arroyo-Currás of the Faculty of Medicine, Johns Hopkins University, Philippe Dauphin-Ducharme of Université de Sherbrooke in Canada; and Philip S. Lukeman of St. John in New York.

The team used equipment to create at the Institute for Nanovience Cauli in Caltech. The work was supported by the Office for Army Research, the Naval Research Office, the National Science Foundation and the Life Research Foundation supported by the Merck Research Laboratory.