A homogeneous hemin/G-quadruplex DNAzyme based turn-on chemiluminescence aptasensor for interferon-gamma detection via in-situ assembly of luminol functionalized gold nanoparticles, deoxyribonucleic acid, interferon-gamma and hemin

A homogeneous hemin/G-quadruplex DNAzyme (HGDNAzyme) based turn-on chemiluminescence aptasensor for interferon-gamma (IFN-gamma) detection is developed, via dynamic in-situ assembly ofluminol functionalized gold nanoparticles (lum-AuNPs), DNA, IFN-gamma and hemin. The G-quadruplex oligomer of the HGDNAzyme was split into two halves, which was connected with the complementary sequence of P1 (IFN-gamma-binding aptamer) to form the oligonucleotide P2. P2 hybridized with IFN-gamma-binding aptamer and meanwhile assembled onto lum-AuNPs through biotin-streptavidin specific interaction. When IFN-gamma was recognized by aptamer, P2 was released into the solution. The two lateral portions of P2 combined with hemin to yield the catalytic hemin/G-quadruplex DNAzyme, which amplified the luminol oxidation for a turn-on chemiluminescence signaling. Based on this strategy, the homogeneous aptasensor enables the facile detection of IFN-gamma in a range of 0.5-100 nM. Moreover, the aptasensor showed high sensitivity (0.4 nM) and satisfactory specificity, pointing to great potential applications in clinical analysis. (C) 2013 Published by Elsevier B.V.