ABSTRACT
This work investigated the interactions of α-Fe2O3 nanoparticles (NPs) with different structural nucleic acids and their fluorescence quenching ability towards fluorophore-labelled nucleic acid probes. Different from bulk α-Fe2O3 samples, nanoscale α-Fe2O3 particles exhibit the unique properties of strong adsorption and fluorescence quenching to fluorophore-labelled single-stranded DNA (ssDNA) probes. Based on these findings, a facile fluorescence method was developed for versatile quantification of nucleic acids. The size scale of NPs makes a significant impact on this sensing platform. Better selectivity was given by bigger NP (50-100 nm)-based nucleic acid-sensing platform compared with smaller NP (30 nm)-based one. In the 50-100 nm α-Fe2O3 NP-based sensing platform, single nucleotide mismatch or single base-pair mismatch can even be effectively discriminated. The targets of micro-RNA (miRNA), ssDNA and double-stranded DNA (dsDNA) are sensitively detected with detection limits of 0.8 nM, 1.1 nM and 0.64 nM (S/N=3), respectively. Significantly, α-Fe2O3 NPs possess different affinities towards ssDNA probes with different lengths, and can be used as a universal quencher for ssDNA probes labelled with different fluorescent dyes. On the basis of these properties, the pristine α-Fe2O3 NPs hold the potential to be widely utilized in the development of novel biosensors with signal amplification or simultaneous multiple target detection strategies.
Subject(s)
Biosensing Techniques , DNA, Single-Stranded/isolation & purification , DNA/isolation & purification , MicroRNAs/isolation & purification , DNA/chemistry , DNA, Single-Stranded/chemistry , Ferric Compounds/chemistry , Fluorescent Dyes , MicroRNAs/chemistry , Nanoparticles/chemistry , Staining and LabelingABSTRACT
A new coordination polymer which shows an unusual 2D inorganic connectivity was constructed. This compound exhibits distinct fluorescence quenching ability to the dye-labeled single-stranded DNA probes with different lengths, based on which an analytical method was developed for the activity assay of deoxyribonuclease I.
Subject(s)
Barium/chemistry , Coordination Complexes/chemistry , DNA Probes/chemistry , Deoxyribonuclease I/metabolism , Polymers/chemistry , Coordination Complexes/chemical synthesis , DNA Probes/analysis , DNA Probes/chemical synthesis , DNA Probes/metabolism , Deoxyribonuclease I/analysis , Enzyme Activation , FluorescenceABSTRACT
As a two-dimensional (2D) ordered porous organic framework (POF), PAF-6 is demonstrated to have an extraordinarily high fluorescence quenching ability to dye-labeled single-stranded DNA (ssDNA). Based on its different affinities to ssDNA and double-stranded DNA (dsDNA), and to ssDNAs with different lengths, PAF-6 is firstly utilized as a simple, cost-efficient, sensitive and selective sensing platform for sequence-specific detection of DNA and activity analysis of exonuclease I (Exo I). In these two systems, the sensing approach is accomplished by simply mixing the dye-labeled ssDNA probe with the targets and PAF-6. The targets of DNA and Exo I are specifically and sensitively detected with detection limits of 0.6 nM and 0.03 U mL-1 (S/N = 3), respectively, by using PAF-6 as a fluorescence quencher of the dye-labeled ssDNA probe. The results of this study suggest that PAF-6 can be developed as an excellent platform for the detection of nucleic acid and nuclease activity. In addition, PAF-6 exhibits a remarkable ability to protect ssDNA probe from enzymatic digestion, which may greatly extend the applications of the proposed ssDNA probe/PAF-6 sensing system to bioanalysis and biomedicine.
ABSTRACT
A luminescent two-dimensional (2D) coordination polymer is demonstrated to be a selective sensing material for the straightforward detection of nitrobenzene via a redox fluorescence quenching mechanism.
