One of the coolest things about molecular biology and the applications thereof is that technology can be developed to handle small amounts of samples for analysis while being extraordinarily sensitive. In previous posts, I have talked about things such as Microarrays and Cantilever Arrays (which are more sensitive and require lower sample volumes for effective functioning) and also about ELISA, which can be used to detect proteins (either antibodies or antigens) by harnessing a reaction where an antigen binds to an antibody. The technology I’m showcasing in this case is an immunosorbent assay and does the same thing as ELISA, but is cheaper, more efficient and does not use enzymes et cetera. It is a microfluidic device.
The device is called the mChip, and is explained in the video that follows.
As little as a microlitre of whole blood is enough to carry out detection of pathogens such as HIV (or the presence of antibodies to it) and the device can be co-opted to handle any other pathogen if so required by modifying what goes in several looping, serpentine regions along the path the sample flows through.
These regions contain, for instance, antigens to which antibodies in the blood sample may bind, a secondary antibody tagged with gold and silver is then added and these will bind to any antibodies in the sample that have already bound to the antigens found in those loops. Excess antibodies can be washed off and excess sample removed (simply by passing it in at one end of the chip and taking it out at the other)
The colouration that the silver imparts can be used for quantitative estimation and to perform diagnosis.
The advantages are that it works with very low quantities of sample, meaning that sample collection is easier (using a drop of blood from a finger prick is easier than withdrawing blood using an intravenously inserted hypodermic needle) and is very quick (and bloody cheap)
The disadvantage, I suspect, could be issues with false positives, but it is solely my intuition at my moment and to see if there is any substance to my suspicion will necessitate large scale field trials.
If you can get past those nasty paywalls, you will be able to find the peer-reviewed research paper that describes the gadget at http://www.nature.com/nm/journal/v17/n8/full/nm.2408.html
That’s all from me this time round.