Fabrication of cost-effective and efficient paper-based device for viscosity measurement.

Abstract Use of paper-based devices for affordable diagnostics is gaining interest due to unique advantages such as affordability, portability, easy disposability and inherent capillarity. As capillary transportation is an integral component of paper-based devices, low sample volume with faster measurement becomes an additional advantage. We have developed a simple, paper-based microfluidic device suitable for measuring the viscosity of Newtonian fluids as well as a few non-Newtonian fluids with sample volume as little as 12–20 μL. The results could be obtained much faster than the conventional methods. A comparative analysis of the results obtained with our paper-based viscometer and with that of the conventional Ostwald viscometer shows a correlation coefficient greater than 0.99. Apart from viscosity measurement, the paper-based devices were tested for protein denaturation and polymer molecular weight determination. Our results show that the paper-based viscometer could be a potential alternative for the conventional viscometers in the viscosity range from 0.9 cP up till ∼40 cP, with added benefits in terms of time, cost and low sample volume requirement. Graphical abstract Image 1 Highlights • Paper-based viscometer (PBV) with correlation coefficient >0.999 w.r.t. Ostwald's. • First PBV to measure viscosity of Newtonian and non-Newtonian fluids. • First report of use of PVB for protein-stability and molecular weight determination. [ABSTRACT FROM AUTHOR]