A low-cost and disposable capillary-based paper sensor for measuring blood-plasma viscosity using a smartphone app

Abstract

Plasma viscosity is a significant biomarker for the detection of several inflammatory diseases such as rheumatoid arthritis, cardiovascular disorders, autoimmune disease, and ischemic heart disorder. The traditional methods to measure viscosities are accurate and provide results rapidly, however, they are expensive, less transportable, and require a costly data acquisition system. Therefore, we develop a simple, inexpensive, portable and disposable paper-based device for the measurement of plasma viscosity with the help of a smartphone app using only 50 µL blood plasma. The developed device works on the fact that the sample having higher viscosity will take longer time to travel a fixed distance on the porous substrate. A 50 µL of plasma sample is loaded onto the device. The time taken by the sample to travel a fixed distance of 30 mm is recorded, and the viscosity value is estimated with an in-house developed smartphone app. Further, the value of viscosity obtained with our device is benchmarked against the gold-standard results obtained from the Brookfield viscometer. An excellent correlation was found between the values measured by both methods with a coefficient of determination (R 2) of 0.9644. The proposed device covers the entire clinical range of blood-plasma viscosity (0.9–4 cP) and can easily distinguish even a small difference of 0.13 cP in the viscosity value. Hence, our developed device renders not only a portable low-cost miniaturised platform but also a device with uncompromised accuracy which can easily be deployed to resource-poor settings as a point-of-care device. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.