Small volume viscometer

NIDDK scientists have developed a capillary-based device and system for measuring the rheological properties of solutions of synthetic and biological polymers. The device automatically serially dilutes and varies the flow rate of a sample, permitting measurement of solution viscosity across wide ranges of concentration and shear rate without changing samples. Viscosity is calculated directly from Poiseuille's law, given the measured difference in pressure between two ends of a capillary tube through which the solution is flowing at a known rate. The device can rapidly and accurately assay solute stability, solute-solvent and solute-solute interactions in solutions of proteins and other macromolecules of biotechnological and pharmaceutical interest, as well as solution injectability.