Synergistic Effect of MWNTs/CeO₂/CHIT Film for Detection of CdSe Nanoparticle Labeled Sequence‐Specific of 35S Promoter of Cauliflower Mosaic Virus Gene

Abstract

A porous composite film was fabricated combining the advantages of multiwalled carbon nanotubes, CeO 2 and chitosan. The synergistic effect of the film improved the immobilization of probe ssDNA. The loaded probe ssDNA was used for detection of CdSe quantum dots labeled target DNA. The DNA hybridization reaction was detected by differential pulse anodic stripping voltammetry of Cd 2 + after the oxidative release of labeled CdSe quantum dots. The established DNA biosensor can discriminate different target sequences associated with 35S promoter of cauliflower mosaic virus gene with relatively wide linear range and low detection limit (2.4 10 À13 mol/L).

Quantum dot-based electrochemical DNA biosensor using a screen-printed graphite surface with embedded bismuth precursor

“…3C). The selectivity is satisfactory and compares favorably to other electrochemical DNA assays [5,6,8,10,14,15].…”

“…The limit of detection (LOD), estimated as the target DNA concentration corresponding to three times the standard deviation of the blank sample signals (0 pmol L −1 target DNA), was 0.03 pmol L −1 . The LOD was comparable to, or lower than, other ASV-QD assays using electroplated mercury-and bismuth-film electrodes [7][8][9][10], while it was lower than chemiluminescence and fluorescence DNA assays using QDs labels [12,14,20]. Moreover, the LOD is comparable with an electrochemical DNA biosensor which performs direct measurements in untreated complex biological matrices [21].…”

“…Nevertheless, in the existing ASV-QD DNA assays, the surfaces on which the DNA assay is performed cannot be used as sensitive transducers for the ASV determination of the metallic ions released from QD labels; therefore, the hybridization/labeling step and the detection step take place at spatially separated surfaces. More specifically, in these applications the biorecognition events are conducted in microwells [3,4], on glass substrates [5], on magnetic beads [6][7][8][9], on carbon nanotubes [10], or on gold surfaces [11][12][13], while the ASV detection step of QDs is carried out at mercury-or bismuth-film sensors prepared via electroplating procedures on rigid glassy carbon electrodes. Besides the existing methodologies involve an additional step for generating the voltammetric detection layer while the electroplated metal-film electrodes present several drawbacks associated with the creation and deposition reproducibility of the Hg or Bi film.…”

Metal Oxide Nanoparticles in Electroanalysis

“…DNA detection is then performed after the target DNA is hybridized to the surface‐immobilized capture probes. Metal oxide nanoparticles function in such biosensors largely to increase the surface area for the immobilization of the capture probes 93–95, 99. This was demonstrated by Noorbaksh et al.…”

Electrochemical DNA Biosensors Based on Labeling with Nanoparticles

“…In QD-based DNA assays, the synthesis of QDs is based on different methodologies, depending on the desirable QD core [4,13,33,34,35,36,37,38,39,40]. In the case of CdTe synthesis, cadmium chloride, mercaptopropionic acid, and distilled water are mixed into flask.…”