'Lab on a chip' micro rheometer to improve viscosity tests dramatically.
The NIST rheometer could be a particularly valuable tool for biotechnologists studying minute quantities of complex materials that must function in confined spaces.
Viscosity, elasticity and how materials flow when subject to a force is the subject of rheology, and the measurements tell a lot about a complicated material like a gel.
"A lot of people in the biosciences are making very complex designer fluids based on proteins where you might make only 10 milliliters at a time. Polypeptide hydrogels for drug delivery or tissue replacement, for example," polymer scientist Gordon Christopher said.
"Their flow behaviors are very complicated and you really need to understand them, but in a traditional rheometer your sample for a single test is a large percentage of what you just spent two months making," he added.
Kalman Migler and his colleagues created the rheometer that is about one-twentieth the size of a postage stamp.
"With our device, if you gave me a milliliter of sample, I could give you back hundreds of tests," Christopher said.
Plus, when the material is meant to be used in a confined region like a blood vessel or the interior of a cell-or must be injected through a thin needle-understanding the flow characteristics of small amounts in a small space is more important than knowing how it behaves in bulk.
In a more polished version, according to the research team, the necessary sensors could be included on the chip and the entire instrument reduced to a handheld device for, e.g., quality control measurements on a plant floor.
The NIST MEMS dynamic rheometer is described in a new paper in Lab on a Chip. (ANI)
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