Developing microscopy based microfluidic SLS assay for on-chip hemoglobin estimation

Abstract

Point-of-care (POC) biochemical assay is a highly important biochemical assay to estimate hemoglobin in the blood. High reagent volumes and complex-expensive optical setup requirements pose serious challenges when it comes to adopting conventional biochemical assays such as the Sodium Lauryl Sulfate (SLS) method into a POC device. Here, we report a modified SLS assay on a microfluidic platform, wherein the quantification is achieved using a simple microscopy-based imaging setup. Assay parameters, including SLS reagent-to-blood volume ratio, total reaction volume, the concentration of sodium dodecyl sulfate, and microfluidic chamber design, were optimized in order to achieve quantitation capability across a clinical range of hemoglobin using a path length suitable for the microfluidic platform. Besides quantitative correlation with a clinically accepted-validated standard method, the spectral absorption characteristics of the hemoglobin–SLS reagent mixture in the newly developed assay were compared with those of conventional SLS assays. The finalized chip design, including the reagent, cost 0.136 USD. The microfluidic chip in combination with an automated microscope was able to achieve a Pearson correlation of 0.99 in a validation study comparing the newly developed method and a commercially available hematology analyzer, with a turnaround time of 10 min, including incubation time. The clinical performance was ascertained, and the method achieved a sensitivity of 92.3% and a specificity of 53.8%. Overall, an automated microscopy-based biochemical assay was developed to estimate hemoglobin in whole-blood, using microfluidics technology, wherein the detector was a conventional camera associated with microscopy.

A novel lab-on-chip cartridge overcoming centrifugation and slide preparation for automated urinalysis

“…Further, these microscopic images are analyzed by Arti cial Intelligence (AI) models to detect and count the elements present in the specimen to generate a report. A crucial point to note is that the same AI100 device has been previously used for automated peripheral blood smear (PBS) (Ethirajan et al 2017;; Chari and Prasad 2018) analysis and the measurement of Hemoglobin (Arcot et al 2021) in blood. The AI100 can be considered a stand-alone device for all three clinical tests: PBS, Hemoglobin and urine microscopy.…”

Simultaneous quantitative detection of hematocrit and hemoglobin from whole blood using a multiplexed paper sensor with a smartphone interface

“…The distance-based hematocrit measurements require a complex flow-channel architecture and ultra-precise control of the dispensed sample volume, to make up for the analytical simplicity. Of late, due to the rapid emergence of advanced optical and electro-mechanical detection technologies, newer variants of POC kits for Hb level detection have been introduced that mostly rely on colorimetric, spectrophotometric, luminescence, and carbon-dot based fluorescence, 2,20–24 as well as electrophoretic principles. 25,26 In addition, electrical impedance spectroscopy (EIS) has emerged as an alternative versatile laboratory-benchmarked principle that inherently offsets various challenges of the traditional diagnostic procedures such as elaborate sample preparation and reagent-driven analysis, as well as the need for complex optical equipment if not otherwise resorting to over-simplified manual interpretation.…”