We report a new point-of-care, multiplexed immunoassay platform based on 3D porous hydrogel particle sensors embedded into a plastic microfluidic device.
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.
Blood is the most analyzed body fluid for diagnostic purposes, and complete blood count is a widely performed blood test, wherein hemoglobin estimation is performed colorimetrically, while other parameters including counts of platelets, Red Blood Cells (RBCs) and White Blood Cells (WBCs) are estimated using imaging or impedance or light scattering techniques. Artificial Intelligence (AI) powered automated imaging systems in conjunction with microfluidic chips are some of the most promising cost-effective medical diagnostic solutions poised to revolutionize the field of Point-of-Care (POC) healthcare. Performing imaging based colorimetry would enable minimizing the cost and also the footprint of POC blood analyzers. We report the development and verification of an imaging based on-chip colorimetric assay to estimate hemoglobin in blood using ultra-low path lengths by transitioning from a widely utilized Q band absorbance peak to a more intense Soret peak associated with Sodium Lauryl Sulfate (SLS) assay. Initial SLS reagent customization characterization of the SLS reagent was performed using a nanospectrophotometer with in-house prepared hemoglobin standards and also whole blood samples. Subsequently, the imaging based SLS assay was optimized on a microfluidic chip (chamber height: 190 µm) in conjunction with an automated microscope (AI-100) equipped with a violet LED whose emission peak coincided with the Soret peak of the SLS–hemoglobin complex. The thus optimized on-chip hemoglobin assay was verified for clinical performance using a sample set consisting of 30 blood samples. The verification study indicated an accuracy (R2) of 0.98, a sensitivity of 100%, and a specificity of 87.5%. Overall, we present an imaging based on-chip hemoglobin assay using a microfluidic chip with ultra-low path lengths by quantifying the Soret peak associated with the customized SLS assay.
Ferrocement panels increasingly are used in low cost housing in developing countries. In order to understand the functional performance of such panels, sound transmission studies previously have been carried out. This work now focuses on the sound transmission performance of ferrocement panels lined with jute fibre. In this study panel elements were cast and tested in a sound transmission suite to experimentally evaluate the sound reduction index.
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