15 June 2016

Chip for finding snips

Graphene chip with DNA probe taught to "spy" on genetic mutations

Denis Strigun, Naked Science

Researchers from the University of California at San Diego have developed a graphene chip that is capable of detecting DNA mutations. This is reported in the journal Proceedings of the National Academy of Sciences (Hwang et al., Highly specific SNP detection using 2D graphene electronics and DNA strand displacement).

The constructed chip is a DNA probe embedded in a graphene field-effect transistor. The probe consists of double–stranded DNA with a sequence encoding a certain type of method for detecting common genetic mutations - single-nucleotide polymorphisms, or snips (single-nucleotide polymorphism, SNP). During the operation of the probe, molecules with a single nucleotide mutation on the principle of complementarity replace one of its chains, and the transistor gives an electrical signal.

According to scientists, individual snips are associated with such pathological conditions as cancer, diabetes, and cardiovascular diseases. At the same time, traditional methods of detecting snips are expensive and are performed on bulky equipment. The new chip, which is barely larger than a pencil eraser, is economical, easy to manufacture and operate. It is assumed that it will be implanted into the patient's body to monitor targeted mutations in real time.

Here and below are drawings from the UC San Diego press release
Engineers develop a new biosensor chip for detecting DNA mutations – VM

"With our research – and this is the key point – we have shown that it is possible to implement a method of replacing a DNA chain on a graphene transistor. This is the first example of combining DNA-based nanotechnology with a high-resolution electrical sensor. The development can be used in conjunction with wireless technologies," said the co–organizer of the work, Michael Hwang.

Another feature of the double-stranded probe was the possibility of increasing its length to detect large segments of DNA. In the experiment, scientists created a probe of 47 nucleotides – this is a record figure in the case of SNP detection. Despite the length, the sequence was characterized by stability, the probe retained sensitivity and high orientation.


In the near future, the researchers intend to ensure the connection of the chip with mobile devices. In addition, it is planned to adapt it to the technique of "liquid biopsy" – a method of diagnosing cancer by cells separated from the tumor and circulating in the blood.

Portal "Eternal youth" http://vechnayamolodost.ru  15.06.2016

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