MB-GNP-I-PCR for purified ESAT-6 detection.
Notes: (A) 3.5% Agarose gel analysis of ten-fold decreasing concentrations of purified ESAT-6 in PBS by MB-GNP-I-PCR: lane M, 20 bp ladder; lanes 1–14, dilutions of ESAT-6 (10 µg/mL to 1 ag/mL); lane 15, no antigen; and lane 16, PCR-positive control (signal DNA). (B) Specificity of functionalized GNPs coupled with rabbit anti-ESAT-6 pAb showing reactivity with ESAT-6 by MB-GNP-I-PCR but no reactivity with other RD antigens and Ag85B: lane M, 20 bp ladder; lane 1, no template DNA; lane 2, ESAT-6; lane 3, CFP-10; lane 4, CFP-21; lane 5, MPT64; lane 6, Ag85B; lane 7, PCR-positive control (signal DNA); and lane 8, no antigen. (C) Sample matrix effect: 3.5% agarose gel analysis of ten-fold decreasing concentrations of purified ESAT-6 in saliva sample from a healthy individual by MB-GNP-I-PCR: lane M, 20 bp ladder; lanes 1–12, dilutions of ESAT-6 (1 µg/mL to 10 ag/mL); lane 13, no antigen; lane 14, no antigen and no detection antibody; lane 15, no template DNA; and lane 16, PCR-positive control (signal DNA). The experiment was performed with six sputum samples and one of the representative figures has been shown.
Abbreviations: ag, attogram; CFP-10, culture filtrate protein-10; ESAT-6, early secreted antigenic target-6; I-PCR, immuno-PCR; MB-GNP-I-PCR, magnetic bead-coupled GNP-based I-PCR; MPT64, mycobacterial protein from species tuberculosis-64; pAb, polyclonal antibody; RD, regions of differences.