We evaluated two ELISA methods to improve the sensitivity and accuracy. Biotin-streptavidin technology was selected to enhance the ELISA limit of detection due to the high binding affinity of biotin-streptavidin. GNP-conjugated biomolecules were selected to improve detection by ELISA. To evaluate these two methods, the early secreted antigenic target-6 (ESAT-6) from Mycobacterium tuberculosis and the anti-ESAT-6 antibody were used.
The detection limit of ESAT-6 was the same with and without GNP due to the saturation of biotin and streptavidin binding. However, higher absorbance was noticed using GNP only.
The proposed modified ELISA can be used to screen different types of common diseases. Additionally, this study showed how several new techniques can improve the detection and accuracy of ELISA.