New DNA nanomachine for rapid detection of HIV

A nanoscale machine composed of synthetic DNA can be used for rapid, sensitive and low-cost diagnosis of many diseases, including HIV and rheumatoid arthritis, scientists say.
An international team of researchers has designed and synthetised a nanometer-scale DNA "machine" whose customised modifications enable it to recognise a specific target antibody.
The new approach may revolutionise the slow, cumbersome and expensive process of detecting the antibodies that can help with the diagnosis of infectious and auto-immune diseases such as rheumatoid arthritis and HIV, researchers said.
The binding of the antibody to the DNA machine causes a structural change (or switch), which generates a light signal.

The sensor does not need to be chemically activated and is rapid - acting within five minutes - enabling the targeted antibodies to be easily detected, even in complex clinical samples such as blood serum.
"One of the advantages of our approach is that it is highly versatile," said senior co-author of the study Professor Francesco Ricci, of the University of Rome, Tor Vergata.

"This DNA nanomachine can be in fact custom-modified so that it can detect a huge range of antibodies, this makes our platform adaptable for many different diseases," Ricci said.
"Our modular platform provides significant advantages over existing methods for the detection of antibodies," added Professor Vallee-Belisle of the University of Montreal, the other senior co-author of the paper.

"It is rapid, does not require reagent chemicals, and may prove to be useful in a range of different applications such as point-of-care diagnostics and bioimaging," Vallee-Belisle said.
"Another nice feature of our this platform is its low-cost," said Professor Kevin Plaxco of the University of California, Santa Barbara.
"The materials needed for one assay cost about 15 cents, making our approach very competitive in comparison with other quantitative approaches," Plaxco said.
The research is published in the journal Angewandte Chemie.