Measuring extensional viscosity of biofluids using electrical breakup rheometry

The analysis of biofluids for medical diagnostics requires new methods for handling low amounts of sample volume while measuring multiple properties. Here we investigate an approach to characterize the extensional rheological properties by applying an electrical field to facilitate a dynamic filament stretching and breakup experiment. The minimum required volume in a single run is in the range of one microliter. The filament lifetime is a measure for the concentration and molecular weight of polysaccharides and the strenghts of the respective network. We use a signal generator to control a high voltage source while monitoring the electrical current. The breakup process is observed using highspeed imaging. Results are presented for alginate model liquids and canine synovial fluid.