Gold Nanoparticle-Mediated High-Performance Enzyme-Linked Immunosorbent Assay for Detection of Tuberculosis ESAT-6 Protein

Background: Tuberculosis (TB) is a life-threatening human disease and ESAT-6 protein in TB is vital for the effective diagnosis, treatment, disease prevention and control. ESAT-6 is an early secretory protein by the pathogen (Mycobacterium tuberculosis), a suitable candidate to detect TB at an early stage. Methods: Enzyme-linked immunosorbent assay (ELISA) is the standard assay used to detect pathogens with higher sensitivity. Since Gold nanoparticle (GNP) is a sensitivity improvement material in biosensor, in this study, we proposed ELISA combined GNP to detect the low abundance of ESAT-6. Results: GNP-assisted ELISA exhibited ~7.5-fold improved detection compared to the conventional ELISA. Larger (80 nm) sized GNP provided a higher sensitivity than smaller (10 nm) sized GNP. The detection limit of this method has attained the level of 1 nM of ESAT-6. Conclusion: This method can be used to detect the presence of ESAT-6 and provides a model for sensitive detection of other pathogens such as HIV and Influenza.