ABSTRACT
A simple, label-free and colorimetric method for coralyne detection was successfully established based on the coralyne-induced formation of split G-quadruplex-hemin DNAzyme. It can achieve a detection limit of 31 nM toward coralyne with excellent selectivity.
Subject(s)
Berberine Alkaloids/analysis , Berberine Alkaloids/pharmacology , Biomimetic Materials/metabolism , Biosensing Techniques/methods , DNA, Catalytic/chemistry , Peroxidase/metabolism , Biomimetic Materials/chemistry , Colorimetry , DNA, Catalytic/metabolism , G-Quadruplexes/drug effectsABSTRACT
A bifunctional fluorescent oligonucleotide probe for small molecules and protein detection has been developed based on turn on fluorescence response via the target induced structure-switching of molecular beacon. The two loops of this molecular beacon are designed in such a manner that they consist of thrombin (Tmb) aptamer sequence and adenosine triphosphate (ATP) aptamer sequence, respectively, which are utilized to sense thrombin and ATP. The oligonucleotide forms double stem-loops in the absence of targets, yielding no fluorescence emission because of the FRET from the excited fluorophore to the proximal quencher. Upon addition of the target, the ATP or Tmb, its specific interaction with loop sequence of the hairpin structure induce the separation of reporter fluorophore and the fluorescence quencher of the molecular beacon, resulting in an increase of fluorescence response. Hence, the separate analysis of ATP and Tmb could be realized through only one designed molecular beacon. The detection limits were estimated to be 25 nM for ATP and 12 nM for Tmb, respectively. The results of this study should substantially broaden the perspective for future development of oligonucleotide probe for analysis of other analytes.
Subject(s)
Adenosine Triphosphate/analysis , Aptamers, Nucleotide/chemistry , Biosensing Techniques/instrumentation , Molecular Probe Techniques/instrumentation , Spectrometry, Fluorescence/instrumentation , Thrombin/analysis , Complex Mixtures/analysis , Equipment Design , Equipment Failure Analysis , Molecular Probes/chemistry , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
A facile, highly sensitive colorimetric strategy for dihydronicotinamide adenine dinucleotide (NADH) detection is proposed based on anti-aggregation of gold nanoparticles (AuNPs) via boronic acid-diol binding chemistry. The aggregation agent, 4-mercaptophenylboronic acid (MPBA), has specific affinity for AuNPs through Au-S interaction, leading to the aggregation of AuNPs by self-dehydration condensation at a certain concentration, which is responsible for a visible color change of AuNPs from wine red to blue. With the addition of NADH, MPBA would prefer reacting with NADH to form stable borate ester via boronic acid-diol binding dependent on the pH and solvent, revealing an obvious color change from blue to red with increasing the concentration of NADH. The anti-aggregation effect of NADH on AuNPs was seen by the naked eye and monitored by UV-vis extinction spectra. The linear range of the colorimetric sensor for NADH is from 8.0 × 10(-9)M to 8.0 × 10(-6)M, with a low detection limit of 2.0 nM. The as-established colorimetric strategy opened a new avenue for NADH determination.
