A smartphone enabled low-cost portable centrifuge integrated with a simple paper-based device for the estimation of plasma-albumin concentration

We are developing a simple, affordable, and biodegradable microfluidic paper-based device (µPAD) for measuring albumin levels using 25 µL of human blood. First, we separate plasma from 25 µL of blood using a portable rotating device. Further, we gently deposit 10 µL of plasma into the µPAD, which is already coated and dried with 8 µL (0.004 M) of Bromothymol blue (BTB). The albumin in the plasma reacts with BTB, and consequently, the color of the detection zone changes from yellow to blue. We use a smartphone to capture the resulting image, and we quantify the albumin level with the help of an in-house developed app (ALB-SENSE). We are comparing the level of albumin measured with the recent device with the gold-standard results, and we observe a strong correlation (R2 = 0.9834) between the two values. In a nutshell, the device for plasma-albumin estimation through a colorimetric assay has true potential for its deployment as a point-of-care device with the involvement of minimally trained human resources in resource-constrained settings where healthcare diagnostic facilities are scarce. The measurement of albumin concentration is performed to figure out various diseases such as kidney damage, liver disease, malabsorption, diarrhoea, eclampsia, and nephrosis. Though clinical assays in gold standard devices as well as miniaturized microfluidic platforms are available for the measurement of plasma albumin, these assays suffer from one or more of the following major shortcomings: (i) complex fabrication and device integration, (ii) less efficacy in blood-plasma separation technique, (iii) Clinical assays are expensive and time-consuming, (iv) involvement of highly skilled technicians, and (v) non-availability of the smartphone app for HSA level measurement. Overcoming the constraints mentioned above, herein, we have developed a hybrid platform to estimate the albumin concentration. Our platform consists of a potable centrifugal device to separate blood plasma with high purity and a paper-based device to detect albumin concentration using an in-house developed app, "ALB-SENSE". The gold-standard clinical assay has been translated in this miniaturized platform without sacrificing its fundamental principle for the determination of plasma-albumin level from the whole human blood, aiming to deploy our hybrid platform with ALB-SENSE app as a perfect candidate for field measurement of plasma-albumin, which would have the greatest possible impact on reducing the burden of above-mentioned disease among the underserved population.