High Catalytic Activity of Fluorophore-Labeled Y-Shaped DNAzyme/3D MOF-MoS₂NBs as a Versatile Biosensing Platform for the Simultaneous Detection of Hg²⁺, Ni²⁺, and Ag⁺ Ions

Abstract

In this study, we have designed a three-fluorophore-labeled Y-shaped DNAzyme with a high catalytic cleavage activity and a three-dimensional (3D) MOF-MoS 2 NB (metal−organic framework fused with molybdenum disulfide nanobox), which was synthesized as an efficient quencher of the fluorescent biosensor. The synthesized porous 3D MOF-MoS 2 NBs and Y-shaped DNAzyme exhibited a good analytical response toward the simultaneous multiple detections of Hg 2+ , Ni 2+ , and Ag + ions over the other coexisting metal ions. More specifically, the three kinds of enzyme aptamer and substrate aptamer (SA) were hybridized and annealed to form the Y-shaped DNAzyme structure and labeled with three different fluorophores such as FAM, TAMRA, and ROX over the 3′-end of SA. When the targets were induced, the DNAzyme was triggered to cleave the fluorophore-labeled SAs. Then, the cleaved SAs (FAM-SA, TAMRA-SA, and ROX-SA) were adsorbed on the 3D MOF-MoS 2 NB surface to quench the fluorescence signal due to a noncovalent interaction (van der Waals and π−π stacking interaction), which transmuted the fluorescence on-state to off-state. As a result, the fluorescence assay confiscated the high selectivity and sensitivity for the target analytes of Hg 2+ , Ni 2+ , and Ag + ions achieved for the detection limits of 0.11 nM, 7.8 μM, and 0.25 nM, respectively. Accordingly, the sensitivity of the developed sensor was explored with a better lower detection limit than the previously reported biosensors. The utility of the designed Y-shaped DNAzyme may find a broad field of application in real water sample analysis with interfering contaminants.

A dual-color fluorescent biosensing platform based on amine functionalized 3D copper Prussian blue nanocubes and exonuclease I activity for simultaneous detection of kanamycin and streptomycin

“…Multicolour fluorescence detection is the most efficient method for detecting multiple biomolecules. [14][15][16] FRET is a method wherein energy is transferred between fluorescence elements (various fluorophores, carbon quantum dots, and up conversion nanoparticles, for example) as donors and quenching materials (metal oxides, graphene oxide, MoS 2 and various MOFs, [17][18][19] for example) as acceptors. Whenever the distance between the donor and acceptor is less than 10 nm, the fluorescence could be quenched due to the overlapping of the energy donor's emission spectrum and the energy acceptor's absorption spectrum.…”

“…Multicolour fluorescence detection is the most efficient method for detecting multiple biomolecules. 14–16…”

A novel near‐infrared fluorescent and colorimetric probe for selective detection of Ag+ and Hg2+

“…In contrast, fluorescent probe detection has attracted much attention due to its rapidity and convenience, short response time, high sensitivity and strong antiinterference ability and over the past years numerous fluorescent probes have been developed for detection of Hg 2+ and Ag + . [6][7][8][9][10][11][12][13] Multifunctional fluorogenic chemosensors for simultaneous or discriminative detection of Hg 2+ and Ag + have also been reported based on metal-organic frameworks (MOFs), [14][15][16] polymers, [17][18][19] DNA, 20,21 quantum dots, [22][23][24] carbon dots, 24,25 gold nanoclusters, 26,27 nanoparticles, 28,29 nanoribbons, 30 fluorescent silk, 31 chromatography paper, 32 and small organic molecules such as 1,8-naphthalimides, [33][34][35] calix [4]arenes, 36,37 BODIPY derivatives, 38 thienyldiketopyrrolopyrrole, 39 9,9 0 -bianthracene, 40 1,8-naphthyridine derivatives, 41 7-nitrobenzo-2-oxa-1,3-diazolyl (NBD), 42 rhodamine B, 43 fluorescein derivatives, 44 coumarins, 45 triarylamine rhodanine der...…”

“…[6][7][8][9][10][11][12][13] Multifunctional fluorogenic chemosensors for simultaneous or discriminative detection of Hg 2+ and Ag + have also been reported based on metal-organic frameworks (MOFs), [14][15][16] polymers, [17][18][19] DNA, 20,21 quantum dots, [22][23][24] carbon dots, 24,25 gold nanoclusters, 26,27 nanoparticles, 28,29 nanoribbons, 30 fluorescent silk, 31 chromatography paper, 32 and small organic molecules such as 1,8-naphthalimides, [33][34][35] calix [4]arenes, 36,37 BODIPY derivatives, 38 thienyldiketopyrrolopyrrole, 39 9,9 0 -bianthracene, 40 1,8-naphthyridine derivatives, 41 7-nitrobenzo-2-oxa-1,3-diazolyl (NBD), 42 rhodamine B, 43 fluorescein derivatives, 44 coumarins, 45 triarylamine rhodanine derivatives, 46 chromene-imidazophenazine, 47 and pyridyl azo compounds. 48 How...…”

Label-free DNAzyme for highly sensitive detection of multiple biomolecules in real samples through target-triggered catalytic cleavage reactions with auramine O’s discriminated fluorescence emission

“…As a consequence, the researcher has transformed DNAzymes into extremely sensitive and selective neutral molecule biosensors using diverse signal transduction techniques such as fluorescence, colorimetric, and electrochemistry. Among them, the fluorescencebased DNAzyme biosensor has received prodigious attention for quantitative analysis of neutral molecules because it is the most competitive, simpler, and compatible [20].…”