Rapid Temperature-Dependent Rheological Measurements of Non-Newtonian Solutions Using a Machine-Learning Aided Microfluidic Rheometer

Abstract

Biofluids such as synovial fluid, blood plasma, and saliva contain several proteins which impart non-Newtonian properties to the biofluids. The concentration of such protein macromolecules in biofluids is regarded as an important biomarker for the diagnosis of several health conditions, including cardiovascular disorders, joint quality, and Alzheimer's. Existing technologies for the measurements of macromolecules in biofluids are limited; they require a long turnaround time, or require complex protocols, thus calling for alternative, more suitable, methodologies aimed at such measurements. According to the well-established relations for polymer solutions, the concentration of macromolecules in solutions can also be derived via measurement of rheological properties such as shear-viscosity and the longest relaxation time. We here introduce a microfluidic rheometer for rapid simultaneous measurement of shear viscosity and longest relaxation time of non-Newtonian solutions at different temperatures. At variance with previous technologies, our microfluidic rheometer provides a very short turnaround time of around 2 min or less thanks to the implementation of a machinelearning algorithm. We validated our platform on several aqueous solutions of poly(ethylene oxide). We also performed measurements on hyaluronic acid solutions in the clinical range for joint grade assessment. We observed monotonic behavior with the concentration for both rheological properties, thus speculating on their use as potential rheo-markers, i.e., rheological biomarkers, across several disease states.

Morphology, repulsion, and ordering of red blood cells in viscoelastic flows under confinement

“…For HA01, where the shear-thinning was scarcely noticeable, we further determined a relaxation time of l = 3.7 AE 1.4 ms using the m-rheometer introduced previously. 40 This value agrees with the relaxation time of l = 2 ms obtained from the cross-model (Table 1). For consistency, we use the relaxation time of l = 2 ms for further analysis.…”

Viscoelastic Particle Encapsulation Using a Hyaluronic Acid Solution in a T-Junction Microfluidic Device

“…To quantify the fluid elasticity, we attempted to measure the longest relaxation time of the solution via conventional small angle oscillatory shear (SAOS) measurements; however, the rheometer was not sufficiently sensitive to detect such small values of . For this reason, we determined by using the -rheometer microfluidic rheometer recently introduced [ 54 , 55 ], obtaining a value of ms.…”

Continuous sheathless particle separation in viscoelastic fluids with different rheological properties

“…Despite many studies on particle separation in viscoelastic fluids, most existing microfluidic devices for sheathless separation only work for the viscoelastic fluid with specific rheological property, which would limit the application of microfluidics technology in practice. For instance, the concentration and the morphology of biological macromolecules in body fluids vary for different people at different time and under different conditions, which would change the rheological property of the body fluids (Giudice and Barnes 2022). The designed microfluidic platform might face the risk of failure in practical application.…”