Paper based Point of Care Testing Device for Liver Function Test

Abstract

The liver disorder is a widespread health problem and a leading cause of morbidity and mortality in developing countries. Liver diseases lead to two million death per year worldwide. Therefore, the early diagnosis of liver diseases is essential to curb mortality and morbidity. This thesis reports the development of a point of care paper analytical device (PAD) for the simultaneous detection of the liver function biomarkers such as bilirubin, serum protein, alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine transaminase (ALT). First, the chromatographic paper was patterned to create hydrophobic barriers using wax printing. Then, the specific reagents were drop-cast on the reagent zones. The colour developed while introducing the sample in the reagent zone was captured using a digital camera or a desktop scanner. A colour band was developed for visual interpretation of the concentration of the biomarker. The images were processed using ImageJ for quantification. In addition to the laboratory samples, PADs were tested with serum and blood samples for validation. PADs for each biomarker were developed and tested at first. Then the design was suitably modified for the simultaneous testing of all the biomarkers on a single PAD. A PAD for the colourimetric assay of bilirubin based on the in-situ reduction of chloroauric acid to gold nanoparticles was developed. The intensity of the purple colour, due to the surface plasmon resonance, increased with the bilirubin concentration in the 0.005 to 1 g/L range. The detection limit was found to be 0.001 g/L. The method was applied to the determination of bilirubin in urine samples. The spiked urine samples exhibit more than 95 % recovery. The colourimetric assay of serum protein on the PAD was performed using tetra bromophenol blue (TBPB) reagent. The quantification was performed by processing the scanned coloured images of the PAD. The total serum protein concentration in the range of 0 to 22 g/dL was measured using the fabricated paper device, ..