Electrochemical DNA sensor for Staphylococcus aureus nuc gene sequence with zirconia and graphene modified electrode

Abstract

In this paper, zirconia (ZrO 2 ) and graphene (GR) nanocomposite was electrodeposited on the surface of carbon ionic liquid electrode (CILE), which was used to construct an electrochemical DNA biosensor. GR was electroreduced from graphene oxide by potentiostatic method, and ZrO 2 nanoparticle was further electrodeposited on GR/CILE by cycling voltammetric scan in a ZrOCl 2 solution. The presence of GR on the electrode surface can provide a highly conductive interface with large surface area for the loading of ZrO 2 nanoparticles. Single-stranded DNA (ssDNA) probe sequences with phosphate group at the 5′ end could be easily immobilized on the surface of ZrO 2 /GR/CILE due to the strong affinity between ZrO 2 and phosphate groups. The ssDNA/ZrO 2 /GR/CILE was applied to hybridize with the target ssDNA sequence, and methylene blue (MB) was used as the electrochemical indicator. Due to the different binding models of MB with double-stranded DNA and ssDNA on the electrode surface, electrochemical response of MB was decreased after the hybridization reaction. Under the optimal conditions, the reduction peak current of MB was proportional to the concentration of Staphylococcus aureus nuc gene sequence in the range from 1.0×10 −13 to 1.0×10 −6 mol L −1 with the detection limit of 3.23 × 10 −14 mol L −1 (3σ). The electrochemical DNA sensor exhibited good selectivity to various mismatched ssDNA sequences, and the polymerase chain reaction amplification products of S. aureus nuc gene sequence were further detected with satisfactory results. Therefore, this electrochemical DNA sensor with ZrO 2 nanoparticles and GR nanosheet modified electrode could be used for the detection of specific ssDNA sequence in real biological samples.

Selective Detection of an Infection Biomarker by an Osteo-Friend Scaffold: Development of a Multifunctional Artificial Bone Substitute

“…The S. aureus specific oligonucleotide (Bioneer or SFC probes, Korea) [ 24 ] was modified with a thiol group and fluorescein amidite (FAM) at the 3′ and 5′ end, respectively (5′-FAM-TGGACGTGGCTTAGCGTATATTT 15 -Thiol-3′). A disulfide bond between probe DNAs (4.26 nmol/mL) was cleaved using DL-dithiothreitol (DTT; 0.1 M in 0.18 M phosphate buffer, pH 8.0, Sigma Aldrich, St. Louis, MO, USA) for 1 h. The liberated probe DNAs were purified using an NAP-10 column (GE Healthcare, North Richland Hills, TX, USA) following the manufacturer’s instructions.…”

Recent advances in airborne pathogen detection using optical and electrochemical biosensors

“…Thus, the S. aureus -contained electrode was dipped in the MB solution and monitored the redox signal variation using the DPV technique. Notably, this fabricated biosensor detected the S. aureus as low as 3.23 × 10 −14 mol L −1 [ 132 ]. Electrochemical immunosensors were impeccably applied to S. aureus detection [ [134] , [135] , [136] , [137] ].…”

Enzyme-based electrochemical biosensors for food safety: a review

“…Another important application of the electrochemical DNA biosensor for the detection of S. aureus nuc gene sequence was found in the concentration range of 1.0×10 −13 -1.0×10 −6 mol/L with an LOD of 3.23×10 −14 mol/L (3σ). 82 Girousi et al 83 fabricated a mitochondria-based amperometric biosensor for the determination of l-glutamic acid in the range of 10±100 mM with a sensitivity of 0.021 µA/mM. Girousi et al 84 again fabricated a mitochondria-based amperometric biosensor for the determination of l-succinic acid in the range of 0.05-0.4 mM with a sensitivity of 0.388 µA/mM, and the detection limit was found to be 0.02 mM.…”