Gold nanoparticle based Tuberculosis immunochromatographic assay: The quantitative ESE Quanti analysis of the intensity of test and control lines

Abstract

A rapid dual channel lateral flow assay for the detection of Mycobacterium Tuberculosis antibodies (MTB 38kDa monoclonal antibody) in human blood was developed. The MTB 6–14–38kDa fusion antigen and anti-Protein A were used as the capture proteins for test and control lines respectively. Protein A labeled 40nm gold nanoparticles were used as the detection conjugate. Whole blood and serum were spiked with MTB 38kDa monoclonal antibody to make a positive sample model. The developed lateral flow was used to test MTB 38kDa monoclonal antibody, and a detection limit of 5ng/ml was used as a cut-off concentration of the analytes. The effect of the analyte concentration on the MTB lateral flow assay was studied using the variation of the intensity obtained from a ESE Quanti reader. There was a direct correlation between the analyte (MTB 38kDa monoclonal antibody) concentration and the intensity of the test line. The intensity increased with an increase in the concentration of MTB 38kDa monoclonal antibody, while in contrast, an increase in analyte concentration decreased the intensity of the control line.