Optical Chip Detects Blood Molecules, within minutes

Technology.am (July 16, 2009) — European researchers have created a portable ‘lab on a chip’ that can identify target molecules in blood samples. It is being used to measure fertility hormones and detect the genes associated with certain types of cancer.

optical chipNow blood result is available within a few minutes. Earlier the testing of blood takes time, samples need to be sent to a laboratory and it may take several days before the result comes back.

The EU-funded NEMOSLAB project is developing an integrated ‘lab on a chip’ that can simultaneously test a sample for several different molecules at the point of care.

NEMOSLAB uses an optical technique to recognise the presence of selected biological molecules. Light passes down a silicon nitride waveguide – a flat rectangular pipe about 8 micrometres wide and 0.15 micrometres thick – to a detector which turns it into an electrical signal.

The waveguide is coated with a probe molecule that can recognise target molecules by binding to them. This could be an antibody, which will bind with a specific protein, or a strand of DNA that will bind with a complementary strand in the sample fluid.

A microfluidics system within the chip passes the sample – normally blood serum – over the waveguide. When a target molecule in the sample binds to the surface of the waveguide the optical properties are changed and the amount of light arriving at the detector also changes. The step in the signal is distinctive.

Each NEMOSLAB chip contains nine waveguides which are exposed to the sample at the same time and can be primed to detect different molecules. The entire chip is fabricated as a single unit.

An electronics package collects the signals from the waveguides and produces the results within a few minutes of the sample being introduced.

Researcher at infertility treatment centre in Dortmund is using the device to monitor hormone levels in the blood of women seeking to conceive a baby through in-vitro fertilisation. The NEMOSLAB device can test for nine different hormones at the same time.

At present, women have to travel to the clinic every day for the tests but with NEMOSLAB they could do the tests themselves at home.

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