baudrunner's space: The laboratory on a chip
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Monday, January 21, 2008

The laboratory on a chip

Disruptive technology is good technology, for it means that a new improved product has appeared that revolutionizes the way things were done before. A materials research group at the University of Rochester has created just such a product by fabricating special porous silicon films. They are membrane filters which permit the passage of protein molecules of a certain size while blocking passage of others too large to fit through the 15-nanometer thick porous layers. The improvement over normal membrane filters is significant. The silicon filter can separate one protein molecule from another that is only twice its weight. Normal membrane filters can't do better than separate molecules that differ in weight by a factor of ten. Practical uses may be in kidney dialysis and in the field of microfluidic "lab-on-a-chip" technologies for medical testing.

Berkeley Lab scientists have also created a disruptive technology they call monolithic porous polymers, a single continuous piece of specialized polymer which replaces the many small polymer beads approach to distributing chemical samples in a microfluidic channel. The channel walls in a normal micro-fluidic chip are coated with the substance which extracts the desired compound from a stream. The rest flows through uncollected. The monolithic porous polymer shows an increase in the efficiency of extracting biological and chemical toxins from air, soil, and water samples by a factor of one thousand.

The Berkeley lab has gone one step farther by interfacing its microfluidics technology with mass spectrometry. They have developed what is called a multinozzle nanoelectrospray emitter array. Daojing Wang is the lead scientist with Berkeley Lab’s Life Sciences Division who leads the proteomics research group. "Ours is the first report of a silicon/silica microfluidic channel that is integrated monolithically with a multinozzle nanoelectrospray emitter," said Wang. Proteomics is the study of proteins that genes encode. Prior to his invention, microfluidic analysis of proteins has been a separate process from mass spectrometry. Now they can be incorporated into a single lab-on-a-chip.

Micropumps, microvalves, and micro flow sensors have been developed to control the movement of fluid on a chip. Future products will aid in environmental monitoring, cell sorting, protein separation, detection of biological weapons, blood analysis, drug screening systems, drug development, and portable DNA analysis. Micro-chips already exist which perform DNA analysis. The driving idea behind lab-on-a-chip is to reduce a chemistry laboratory and all of its capabilities to a microscopic level.

The blood test lab-on-a-chip is already here. Research at Caltech, funded by NASA, was aimed at creating a small device capable of carrying out blood tests on astronauts in space. The large size and complexity of existing systems made them unsuitable for use in outer space. The device gives a count of red and white blood cells. The research team which developed the device believes the new technology may be adapted for analyzing fluids such as blood plasma and urine and even as a tool for cancer detection and DNA analysis.

NASA has developed what appears to be the first practical tricorder in the LOCAD-PTS, a handheld biological laboratory for space travel. It has already been used to detect microorganisms such as fungi and bacteria on surfaces aboard the International Space Station.

The first true multifunction lab-on-a-chip comes from the labs at the University of Alberta's Alberta Cancer Diagnostic Consortium (ACDC). Tests are being added to the device as they are being adapted for on-chip testing. Thus far a genetic test for childhood lymphocytic leukemia; a test for chromosomal abnormalities in molecular myeloma and follicular lymphoma, two diseases of the immune system; and a test to detect high viral loads in urine samples have been adapted to the chip.

I think we all know what the future holds.

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