A team of researchers from UC Berkeley, Dublin City University, and Universidad de Valparaíso Chile have developed a self-powered microfluidic chip capable of separating plasma from blood cells and subsequently detecting biotin (vitamin B7) in the sample. The process takes about ten minutes, requires only a 5 microliter sample, and is capable of detecting biotin at 1 part per 40 billion.
For the new SIMBAS biochip, the researchers took advantage of the laws of microscale physics to speed up processes that may take hours or days in a traditional lab. They note, for example, that the sediment in red wine that usually takes days to years to settle can occur in mere seconds on the microscale.
The SIMBAS biochip uses trenches patterned underneath microfluidic channels that are about the width of a human hair. When whole blood is dropped onto the chip’s inlets, the relatively heavy red and white blood cells settle down into the trenches, separating from the clear blood plasma. The blood moves through the chip in a process called degas-driven flow.
For degas-driven flow, air molecules inside the porous polymeric device are removed by placing the device in a vacuum-sealed package. When the seal is broken, the device is brought to atmospheric conditions, and air molecules are reabsorbed into the device material. This generates a pressure difference, which drives the blood fluid flow in the chip.
In experiments, the researchers were able to capture more than 99 percent of the blood cells in the trenches and selectively separate plasma using this method.
“This prep work of separating the blood components for analysis is done with gravity, so samples are naturally absorbed and propelled into the chip without the need for external power,” said Dimov.
Link @ Berkeley: New blood analysis chip could lead to disease diagnosis in minutes…
Abstract in Lab on a Chip: Stand-alone self-powered integrated microfluidic blood analysis system (SIMBAS)