Steve Quake's lab has been making a name for itself in attempts to use single cells for genomic studies, so it makes sense that his team pioneered the use of a microfluidics-based chip to perform multiple displacement amplification with single cells. When Paul Blainey joined the lab two years ago, his job was to help scale up the technology for use in higher-throughput cell sorting.
The problem: "It turned out it was difficult to scale the purely fluidic method for sorting up to larger devices that could do more amplifications at once," Blainey says. In a presentation he gave at the American Society for Microbiology's annual meeting in Philadelphia this spring, he offered a glimpse of the laser trapping solution he's come up with.
Blainey added a new technology to the mix. "I had the idea to use laser tweezers to do the sorting, rather than just push the bugs around on the chip using fluid flows," he says. The laser tweezers, which look something like a pair of chopsticks manipulating a cell, offer a greater degree of precision and control — and they also let the user "exclude all the junk that might be coming along with the cell from the sorting solution," Blainey adds. While the microfluidic approach required reconfiguring valves to move cells around — a process that tended to have unintended effects on the rest of the contents of the chip — the laser tweezers "can do this precise manipulation without any sort of side effects going on," he says.
Now that the platform is at a fairly robust level, Blainey says the next step will be to use it to "churn through a lot of samples" that Quake and his collaborators have. The laser cell sorting tool will really come in handy for sorting cells in projects that aim to amplify individual genomes, Blainey says.
Technically speaking, the technology could be reproduced in other labs — all of the components are readily available, but Blainey says the tricky part is "integrating it all and engineering it at the systems level." The microfluidics chip, which is used as part of the process, is made by the Stanford Microfluidics Foundry and can be ordered online, Blainey says.