Microrheometer for Biofluidic Analysis: Electronic Detection of the Fluid-Front Advancement

Abstract

The motivation for this study was to develop a microdevice for the precise rheological characterization of biofluids, especially blood. The method presented was based on the principles of rheometry and fluid mechanics at the microscale. Traditional rheometers require a considerable amount of space, are expensive, and require a large volume of sample. A mathematical model was developed that, combined with a proper experimental model, allowed us to characterize the viscosity of Newtonian and non-Newtonian fluids at different shear rates. The technology presented here is the basis of a point-of-care device capable of describing the nonlinear rheology of biofluids by the fluid/air interface front velocity characterization through a microchannel. The proposed microrheometer uses a small amount of sample to deliver fast and accurate results, without needing a large laboratory space. Blood samples from healthy donors at distinct hematocrit percentages were the non-Newtonian fluid selected for the study. Water and plasma were employed as testing Newtonian fluids for validation of the system. The viscosity results obtained for the Newtonian and non-Newtonian fluids were consistent with pertinent studies cited in this paper. In addition, the results achieved using the proposed method allowed distinguishing between blood samples with different characteristics.

Blood Rheological Characterization of β-Thalassemia Trait and Iron Deficiency Anemia Using Front Microrheometry

“…The experimental setup used consists of a microfluidic channel with 24 gold electrodes, a pumping source, and a computer terminal ( Méndez-Mora et al, 2021 ). A series of shear rates is obtained by applying a set of pressures on the sample fluid.…”

“…Thanks to the mass conservation principle, the flow inside the system is , where Q t and v t , are the flow and velocity inside the tube, respectively, and Q is the flow inside the channel ( Méndez-Mora et al, 2021 ). The relation is valid for the coupled system and ΔP t can be written as:…”

“…In this work, a PoC front-microrheometer with electronic detection is used to characterize blood samples from different donors. The viscosity value as a function of the shear rate of the blood front is measured, details on the mathematical model developed can be found in previous works ( Trejo-Soto et al, 2017 , Trejo-Soto et al, 2018 ; Méndez-Mora et al, 2021 ). Three types of samples are analyzed: control samples from healthy donors, and blood samples from IDA and β-TT patients.…”

Microfluidics Approach to the Mechanical Properties of Red Blood Cell Membrane and Their Effect on Blood Rheology

“…However, the rise of microfluidics at the end of the 1990s brought new applications and innovation in this area. In recent years, a variety of microfluidics devices and methods have been developed with the objective of measuring the viscosity of blood plasma [124][125][126][127] and blood [128], using optical detection techniques [75,[129][130][131][132][133][134], pressure sensors [135,136] and electrical sensors [137][138][139]; see Figure 6. In a capillary, the viscosity of the fluid is measured by establishing the relation between the pressure difference exerted on the fluid and the flow velocity.…”

A Review of Microfluidic Devices for Rheological Characterisation

“…They also measured several bovine serum albumin solutions at different concentrations and found good agreement with the literature data. In the attempt of removing the dependency from optical cameras, Mendez-Mora et al [46] embedded an electronic sensor to detect the liquid-air front. They employed their device to measure the shear viscosity of blood at different hematocrits levels across two order of magnitude in shear-rate.…”