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By employing DNAzyme as a recognition group and amplifier, and DNA-stabilized silver nanoclusters (DNA/AgNCs) as signal reporters, we reported for the first time a label-free catalytic and molecular beacon as an amplified biosensing platform for highly selective detection of cofactors such as Pb2+ and l-histidine. [ABSTRACT FROM AUTHOR]

DNA performsa vital function as a carrier of genetic code, but in the field ofnanotechnology, DNA molecules can catalyze chemical reactions in thecell, that is, DNAzymes, or bind with target-specific ligands, thatis, aptamers. These functional DNAs with different modifications havebeen developed for sensing, imaging, and therapeutic systems. Thus,functional DNAs hold great promise for future applications in nanotechnologyand bioanalysis. However, these functional DNAs face challenges, especiallyin the field of biomedicine. For example, functional DNAs typicallyrequire the use of cationic transfection reagents to realize cellularuptake. Such reagents enter the cells, increasing the difficulty ofperforming bioassays in vivo and potentially damaging the cell’snucleus. To address this obstacle, nanomaterials, such as metallic,carbon, silica, or magnetic materials, have been utilized as DNA carriersor assistants. In this Account, we describe selected examples of functionalDNA-containing nanomaterials and their applications from our recentresearch and those of others. As models, we have chosen to highlightDNA/nanomaterial complexes consisting of gold nanoparticles, graphene oxides, and aptamer–micelles, and we illustrate the potentialof such complexes in biosensing, imaging, and medical diagnostics. [ABSTRACT FROM AUTHOR]

Taking advantage of the super-quenching effect of the cationic perylene derivative on adjacent fluorophores, we for the first time reported a DNAzyme–perylene complex-based strategy for constructing fluorescence catalytic biosensors with improved sensitivity. [ABSTRACT FROM AUTHOR]

DNAzyme-based catalytic beacons have been widely studied for both in vivo and in vitro molecular detection. However, only a few label-free catalytic beacons with excellent analytical performance have been reported so far. In this work, by combining a catalytic DNAzyme for amplified sensing through enzymatic turnover with cleavage-induced G-quadruplex formation, a label-free DNAzyme biosensor was developed for amplified “turn-on” fluorescence detection of Pb 2+ with a detection limit of 3 nM. The method is very competitive compared to many other labeled or label-free methods with or without signal amplification. Due to the inherent specificity of the GR-5 DNAzyme, the method also exhibits excellent selectivity. This biosensor successfully detected Pb 2+ in river water samples with high sensitivity and selectivity. Such a method might provide a universal DNAzyme-based sensing platform for sensitive detection of various targets both in environmental and biomedical fields. [ABSTRACT FROM AUTHOR]

Review: 132 refs. [ABSTRACT FROM AUTHOR]