Fiber Optic Assisted Optofluidic Viscometer for Biomedical Applications

Abstract

Abstract Optical fiber technology is gaining increasing importance in all those fields requiring reliable, miniaturized, compact, and plug‐and‐play devices, with a special relevance in life science applications. Here, optical fibers are adopted to measure the fluids viscosity, by detecting the transit time (related to viscosity) of a steel bead moving through the tested fluid in a microfluidic channel under constant pressure. The proposed optofluidic system is designed by defining a theoretical model, here experimentally validated in the viscosity range of 5–110 cP, well resembling main blood flow features. The achieved results demonstrate the capability to work in multi‐point and single‐point detection modalities with a trade‐off between resolution (minimum of 10−1 and 1 cP respectively) and measurement time (tens of seconds and milliseconds range, respectively). An optimum accuracy close to 1.5% has been achieved, with room for further optimization by reducing bead size uncertainty. The proposed platform features simple, low‐cost, reliable, and fast measurements and ensures the integration with microfluidics chip in a miniaturized and disposable system. The low volumes required (scalable down to µL range) and the ease of use enable the translation of the proposed platform in clinical scenarios involving real‐time blood and plasma viscosity measurements under physiological conditions.

Keywords

• blood viscosity
• microfluidics
• optical fibers
• viscosity measurement