An electrochemical genosensor for Leishmania major detection based on dual effect of immobilization and electrocatalysis of cobalt-zinc ferrite quantum dots

• Published in: Talanta (Oxford) 2016-08, Vol.156-157, p.172-179
• Main Authors: Heli, H., Sattarahmady, N., Hatam, G.R., Reisi, F., Vais, R. Dehdari
• Format: Article
• Language: English
• Subjects: Biosensing Techniques - methods; Cobalt - chemistry; Deoxyribonucleic acid; DNA biosensor; DNA, Single-Stranded - chemistry; DNA, Single-Stranded - genetics; Electrocatalysis; Electrochemical Techniques - methods; Electrodes; Ferric Compounds - chemistry; Ferrite; Humans; Immobilized Nucleic Acids - chemistry; Immobilized Nucleic Acids - genetics; Leishmania major; Leishmania major - genetics; Leishmania major - isolation & purification; Leishmaniasis, Cutaneous - diagnosis; Leishmaniasis, Cutaneous - parasitology; Limit of Detection; Magnetic nanoparticles; Markers; Methylene blue; Nucleic Acid Hybridization - methods; Parasites; Quantum dots; Quantum Dots - chemistry; Quantum Dots - ultrastructure; Signal-on genosensor; Zinc - chemistry
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2016.04.065

Identification of Leishmania parasites is important in diagnosis and clinical studies of leishmaniasis. Although epidemiological and clinical methods are available, they are not sufficient for identification of causative agents of leishmaniasis. In the present study, quantum dots of magnetic cobalt-zinc ferrite (Co0.5Zn0.5Fe2O4) were synthesized and characterized by physicochemical methods. The quantum dots were then employed as an electrode modifier to immobilize a 24-mer specific single stranded DNA probe, and fabrication of a label-free, PCR-free and signal-on electrochemical genosensor for the detection of Leishmania major. Hybridization of the complementary single stranded DNA sequence with the probe under the selected conditions was explored using methylene blue as a redox marker, utilizing the electrocatalytic effect of the quantum dots on the methylene blue electroreduction process. The genosensor could detect a synthetic single stranded DNA target in a range of 1.0×10−11 to 1.0×10−18molL−1 with a limit of detection of 2.0×10−19molL−1, and genomic DNA in a range of 7.31×10−14 to 7.31×10−6ngμL−1 with a limit of detection of 1.80×10−14ngμL−1 with a high selectivity and sensitivity. [Display omitted] •Co0.5Zn0.5Fe2O4 dots were synthesized and characterized.•A 24-mer specific single stranded DNA probe was immobilized on the quantum dots.•A label-free, PCR-free and signal-on electrochemical genosensor for the detection of Leishmania major was developed.