Centrifugable Multiplexer Targeting Frugal Point-of-Care-Testing

Development of a 3-D printed centrifugable multiplexer (CM) has been reported. The CM is an integration of an array of connected microchambers and microchannels, which facilitates dispensation of liquid analytes of fixed volume, facile transport of them, and mixing of them while enabling an in situ reaction of the reagents. The integrated arrangement can also be centrifuged easily besides allowing the usage of multiple analyses platforms in a single unit. In order to demonstrate such efficacies, we perform a few test cases using the CM, e.g., the estimation of: 1) total protein using Biuret’s reagent and 2) albumin using the bromocresol green (BCG) method. In this direction, initially, the calibration for both the markers have been obtained using the known concentrations of the analytes. In both the situations, the centrifugations of the reagent and the analyte in the CM have been performed for a specified time to promote: 1) dispensation of a fixed volume of analyte; 2) controlled transport of liquid reagents through the channels; 3) in situ mixing of analytes; and 4) reactions inside the sensing chambers. Subsequently, the sensing microchambers are illuminated with a light-emitting diode (LED) before obtaining high-quality images of the variations in the colors with the change in the concentrations of the markers by using a mobile phone. The proposed 3-D printed CM has an average intra-CM variability of 1.56%, with variation as low as 0.42, and attained significant linearity for various concentrations of total protein and albumin.