A new silicon chip could enable patients to be tested for a multitude of different viral infections in just a few minutes, says a US company. The chip, developed by BioForce Nanosciences in Ames, Iowa, uses a microscopic array of antibodies to catch the microbes.
The company has so far developed a prototype that can detect six different strains of coxsackievirus B, a virus that can infect hearts and cause transplants to be rejected.
The antibodies are printed onto the silicon chip using a “nano-arrayer”. This places a few thousand antibody molecules on a region measuring one micron in diameter. The process is then repeated for each different antibody. The molecules stick to the silicon thanks to a pre-treatment which coats it with chemicals.
To test for viruses, the chip is simply dipped into a small blood sample. Any viruses present are then captured by the relevant antibodies. This creates telltale ridges on the chip that are detected using an atomic force microscope (AFM).
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“The chip uses a very simple concept,” says Eric Henderson, founder and chief scientist at BioForce Nanosciences. He says the chip is faster than existing virus detection techniques, because the dipping only takes a moment and the AFM analysis can be done in minutes.
Viral fragments
The most common methods currently used involve testing for viral DNA fragments, or for associated enzymes.
Henderson believes his company’s chip would be less likely to produce a false diagnosis because the whole viruses are needed to produce a signal, not fragments. He also adds that the blood samples are unaffected by the testing and could therefore be used for other lab work.
“The idea is excellent,” says Mukesh Verma of the Cancer Biomarker Research Group at the US National Cancer Institute in Maryland. But he cautions that some antibodies might attract more than one strain of virus. “The problem is cross-contamination,” he suggests.
BioForce Nanosciences is working on versions of the chip that can test for more viruses – Henderson says putting 50 antibodies on a chip is perfectly feasible. The company hopes to develop a commercial version to test for common diseases such as hepatitis and HIV.
Journal reference: Nanotechnology (DOI: 10.1088/0957-4484/15/3/027)
