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epoxy.” Trouble shooting that setup takes several days, before the actual continence of the chip can be assessed. Chips that pass the Schweppes test go on to electricity-flow testing. Studying this electro-osmotic flow is Aaron Osher ’13. Working with Ryan Ahern ’14—whose “real” summer job is at the mall pretzel shop but who volun- teers on the research team—Osher uses a laser system devised by Frederick and former students (with, you might think, a nod to Rube Goldberg). Osher flips a few switches on a tabletop full of clamps, wires, clear plastic boxes, screws in a metal pegboard, and duct tape, plus two high-tech lasers and a zigzag array of optical splitters and deflectors. Elec- tricity sends fluorescent dye through a clear hairlike tube analogous to a chip’s tiny conduit, the lasers pulse on and off


“LAB ON A CHIP” PIONEERS AARON OSHER ’13, LELAND MARTIN ’14, SARAH BASHAW ’11, DENISE CROOTE, PROF. KIM FREDERICK, RYAN AHERN ’14, AND BRENDA OLIVO ’14


OSHER FLIPS A FEW SWITCHES ON A TABLETOP FULL OF CLAMPS, WIRES, CLEAR PLASTIC BOXES, SCREWS IN A METAL PEGBOARD, AND DUCT TAPE, PLUS TWO HIGH-TECH LASERS AND A ZIGZAG ARRAY OF OPTICAL SPLITTERS AND DEFLECTORS.


just so, and, he says, “a sensor detects the fluorescent flashes to measure the speed of the dye’s progress.” He adapted and wrote computer code to analyze the masses of compiled data—as many as 250,000 data points comprise one dense graph yielding just one or two numbers that he needs for his calculations—so that he can develop mathematical models of the system. With such tiny amounts of liquid, the walls of the tube affect the flow significantly. Frederick says, “If the solution inside the channel changes, then the overall flow changes. It can make the results of analy- ses different each time, which really limits the use of this technol- ogy in the real world.” Osher explains,


“We’re looking at these inconsistencies, while they’re actually happening inside the tube, and trying to predict and control them.” (Frederick knows only one other American lab using this method to measure fluid flow.) Osher’s experiments use dyes at different pHs, because a higher pH is known to cause faster flow, and lower is slower. With two small beakers on a carousel, he can rotate a different dye solution into the capillary very quick- ly. What he measures is how the rate of flow changes when he adds a different solution that alters the pH in the capillary. Glitches happen, of course: the current surges a bit, the vac- uum comes unsealed, the temperature fluctuates. Any of these can produce anomalous, erratic data, which Osher has to rec- ognize and weed out. In those cases, about 90 minutes of test- ing must be repeated. When he gets a clean run, and later graphs the magnitude of the change in pH against the laser-


measured velocity of the liquid, “we should get an exponential curve, with steeper velocity curves as we have bigger pH changes.” Still needed are more repeats of his experiments, to amass a larger data set.


Meanwhile, new graduate Sarah Bashaw ’11 is honing meth- ods for detecting compounds in very small concentrations. She’s training Martin and Osher to use a capillary electrophoresis instrument, where she loads thin tubes, just 1/25th as wide as a human hair, with minuscule plugs of a guanosine-gel filtration medium and adds tiny squirts of weak protein and saltwater so- lutions. The idea is to concentrate the protein-containing solu- tion when it’s already inside a capillary, which is how it needs to be done in a “lab on a chip.” Bashaw says, “Since guanosine is so fussy about its conditions, we’re also trying a new gel prod- uct called Osorb, which absorbs organic molecules.” In a rack of vials, she’s tracking how fast it absorbs dye and how well it re- leases it again when heated. By summer’s end she’s succeeded in concentrating and detecting insulin, casein, and albumin. Her goal: “Get some parameters figured out, such as the minimum concentrations needed and the saturation limits of the gels, and leave that information behind for the next students.” “This is great experience in the real world of work,” says Fred- erick. And in life lessons as well. Sophomore Olivo admits, “In the beginning, I was shocked at how many things can go wrong! Then I got used to the process and more patient. And I’m mak- ing progress faster now that I have the knowledge I gained from the earlier problems.” She adds, “I never get bored. We use so many techniques, there’s always something new to work with.” In September these and nearly 70 other projects from up- state colleges were presented at a research conference at Skid- more. It was the first such event by the foundation-funded consortium of Skidmore, Union, Colgate, Hamilton, St. Law - rence, Siena, and St. Rose.


WINTER 2012 SCOPE 17


GARY GOLD


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