杏吧原创

TINY barcodes could offer a cheap way to tell which bugs are making you sick
by allowing doctors to screen samples of blood, saliva or urine for common
microorganisms.

The barcodes, developed in Britain by SmartBead Technologies of Cambridge,
are etched onto microscopic aluminium wafers using techniques developed by
silicon chip makers. Each wafer is also loaded with an antibody or DNA probe
that recognises and binds to a specific pathogen or DNA sequence. To tell which
wafer has captured an organism, doctors will treat them all with a mixture of
the same probes鈥攅xcept that they are attached to a chemical that glows. So
any target organism or molecule will end up attached to both a glowing molecule
and a barcoded sliver.

To analyse the results, doctors will fix an attachment to their microscopes
that feeds images of the wafers into a computer. The SmartBead software then
detects any glowing wafers and reads their barcodes.

For more sophisticated or bulk screening, the company has adapted machines
called flow cytometers. 鈥淭hese could screen many thousands of wafers per
minute,鈥� says managing director Caroline Garey.

The technology is similar to that used in DNA or biochips, but Garey says the
method is far more flexible. Doctors could mix and match wafers for different
patients, whereas biochips carry out a fixed set of tests and analysing them
requires more expensive equipment. The company, which hopes its test will become
as routine as checking blood pressure, is now seeking commercial partners to
develop the technology further.

鈥淚t鈥檚 a fun approach,鈥� says Tony Turner, an expert on biosensors at Cranfield
University in Bedfordshire. 鈥淚t鈥檚 a good idea to have independent particles that
are labelled and coded.鈥� Other researchers have tried this with particles such
as glass beads, Turner says, but this is the first attempt he鈥檚 heard of using
slivers of metal.