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

• Published in: Electrochemistry communications Vol. 60; pp. 47 - 51
• Main Authors: Kokkinos, Christos, Prodromidis, Mamas, Economou, Anastasios, Petrou, Panagiota, Kakabakos, Sotirios
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2015
• Subjects: DNA; Electrochemical biosensor; Quantum dots; Screen-printed electrode; Stripping voltammetry; Screen-printed electrode; Stripping voltammetry; Electrochemical biosensor; Quantum dots; DNA
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2015.08.006

This work reports the development of screen-printed quantum dots (QDs)-based DNA biosensors utilizing graphite electrodes with embedded bismuth citrate as a bismuth precursor. The sensor surface serves both as a support for the immobilization of the oligonucleotide and as an ultrasensitive voltammetric QDs transducer relying on bismuth nanoparticles. The utility of this biosensor is demonstrated for the detection of the C634R mutation through hybridization of the biotin-tagged target oligonucleotide with a surface-confined capture complementary probe and subsequent reaction with streptavidin-conjugated PbS QDs. The electrochemical transduction step involved anodic stripping voltammetric determination of the Pb(II) released after acidic dissolution of the QDs. Simultaneously with the electrolytic accumulation of Pb on the sensor surface, the embedded bismuth citrate was converted in situ to bismuth nanoparticles enabling ultra-trace Pb determination. The biosensor showed a linear relationship of the Pb(II) peak current with respect to the logarithm of the target DNA concentrations from 0.1pmol L−1 to 10nmolL−1, and the limit of detection was 0.03pmol L−1. The biosensor exhibited effective discrimination between a single-base mismatched sequence and the fully complementary target DNA. These “green” biosensors are inexpensive, lend themselves to easy mass production, and hold promise for ultrasensitive bioassay formats. [Display omitted] •Screen-printed voltammetric DNA biosensor modified with Bi-citrate was developed.•Hybridization, labeling, and detection steps take place on the same surface.•PbS quantum dots nanocrystals were used as labels.•In situ formed Bi nanoparticles provide ultra-trace detection of released Pb(II).•These sensors address the limitations of voltammetric quantum dot-based biosensors.