Label-Free DNA Assay by Metal Stable Isotope Detection

Abstract

The interest in label-free bioassays is increasing rapidly because of their simple procedure and direct information on the interaction between the target molecule and the sensing unit. One of the major obstacles in the application of label-free biosensors is the difficulty to produce stable and reproducible optical, electric, electrochemical, or magnetic properties for the sensitive detection of the target molecules. In this work, we demonstrated a label-free DNA assay, by directly measuring the intrinsic Cu andCu stable isotopes inside the double-strand DNA-templated Cu nanoparticles. The experimental conditions, including detection of copper by elemental mass spectrometry, the copper nanoparticles formation parameters, the hybrid chain reaction parameters, and analytical performance, were investigated in detail. The Cu signal intensity possesses a linear relation with the concentration of target DNA over the range of 20-1000 pM with a detection limit of 4 pM (3σ). The detection limit of this method is among the most sensitive label-free techniques and also comparable to the lanthanides and Au nanoparticles labeled assays by elemental mass spectrometric detection. The proposed label-free bioassay is simple and sensitive and eliminated the need for optical, electric, electrochemical, or magnetic properties of the sensing unit. To our best knowledge, this is the first report of the label-free bioassay by metal stable isotope detection.

DNA‐Templated Copper Nanoprobes: Overview, Feature, Application, and Current Development in Detection Technologies

“…A further modification of the same approach led to the development of a highly sensitive HCR based bioassay in which intrinsic Cu isotopes ( 63 Cu and 65 Cu) with the formed DNA-templated Cu-NPs were detected by ICPMS ( Figure 5(B)). [57] The method acquired a linear relation with the concentration of target DNA over the range of 20-1000 pM with a detection limit of 4 pM. This method provided the first report on the label-free DNA sensing bioassay based on metal stable isotope detection.…”

“…This design showed potential in the quantitative detection of DNA for biological and medical applications. A further modification of the same approach led to the development of a highly sensitive HCR based bioassay in which intrinsic Cu isotopes ( 63 Cu and 65 Cu) with the formed DNA‐templated Cu‐NPs were detected by ICPMS (Figure (B)) . The method acquired a linear relation with the concentration of target DNA over the range of 20–1000 pM with a detection limit of 4 pM.…”

“…[54] The sequence-dependent fluorescence intensity decreased in the following order; AT > TA > AA > CA > GA > AG > AC > GT > TG > TC > CT > TT > CG > GG > GC > CC. This finding provided a possibility to identify the single-nucleotide [54] hybridization chain reaction (HCR) by ICPMS (B); [57] and rolling circle replication (C); [58] rolling circle amplification (D); [59] genotyping by polymerase chain reaction (E); [60] T7 exonuclease-assisted cascade signal amplification by electrochemistry (F) [63] by DNA-templated Cu-NPs. Reproduced with permission.…”

“…Bio/chemical compound [81c] nn nn nn nnn nn DNA-RNA [62] Chemiluminometric DNA-RNA [81d] nn nnn n n n ICP-MS TNT [47] n nnn n nn n DNA [57] *To be improved: n ; general: nn ; better: nnn…”

Copper nanocluster‐based fluorescence enhanced determination of d‐penicillamine

“…Benefiting from their excellent luminescence properties, copper nanoclusters (Cu NCs) have been successfully applied in fluorescence analysis . In this study, based on the properties of d ‐PA and copper interaction demonstrated in the treatment of Wilson's disease, we established a sensitive and selective method for determination of d ‐PA using Cu NC‐based fluorescence enhancement.…”