Surface Enhanced CdSe/ZnS QD/SiNP Electrochemical Immunosensor for the Detection of Mycobacterium Tuberculosis by Combination of CFP10-ESAT6 for Better Diagnostic Specificity.

Siti Khadijah Ab Rahman,Siti Fatimah Abd Rahman,Noremylia Mohd Bakhori,Jaafar Abdullah,Nor Azah Yusof,Helmi Wasoh

doi:10.3390/ma13010149

Siti Khadijah Ab Rahman, Siti Fatimah Abd Rahman + Show 4 more

Open Access

https://doi.org/10.3390/ma13010149

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Journal: Materials	Publication Date: Dec 31, 2019
Citations: 25	License type: CC BY 4.0

Affiliation: Universiti Putra Malaysia

Abstract

In this study, an electrochemical immunosensor was introduced for the detection of tuberculosis (TB) via utilization of a modified electrode containing a quantum dot (CdSe/ZnS QD) and functionalized silica nanoparticles (SiNPs) on screen-printed carbon electrode (SPCE) CdSe/ZnS QD/SiNPs/SPCE, by employing indirect enzyme-linked immunosorbent assay (ELISA). Here, the fabricated electrode was linked to the biocatalytic action of enzyme catalase through antigen–antibody binding for the detection of the antigen (CFP10–ESAT6) by means of producing a differential pulse voltammetry (DPV) current. The characterization and cyclic voltammetry (CV) of the modified electrode showed good electrochemical behavior and enhanced high electron transfer between the electrode and analyte. Moreover, the active surface area was 4.14-fold higher than the bare SPCE. The developed method showed high selectivity towards CFP10–ESAT6 compared with the other TB proteins. The detection of CFP10–ESAT6 also showed a linear response towards different concentrations of CFP10–ESAT6 with R2 = 0.9937, yielding a limit of detection (LOD) of as low as 1.5 × 10−10 g/mL for a linear range of 40 to 100 ng/mL of CFP10–ESAT6 concentration. The proposed method showed good reproducibility of target analyte with a relative standard deviation of 1.45%.

Highlights

Tuberculosis (TB) is the leading cause of death among bacterial infectious diseases [1]
This study introduces an electrochemical immunosensor that utilizes a screen-printed carbon electrode (SPCE), which offers various advantages, such as low cost, portability, and simple operation
The hydrophobic ligands around surface of QD groups were replaced by hydrophilic ligand from thioglycolic acid (TGA), (-S)

Summary

Introduction

Tuberculosis (TB) is the leading cause of death among bacterial infectious diseases [1]. TB is normally caused by airborne bacterial infection from Mycobacterium tuberculosis (Mtb) [3]. This infection normally targets the lungs (pulmonary TB), but it could attack the kidney, brain, and Materials 2020, 13, 149; doi:10.3390/ma13010149 www.mdpi.com/journal/materials. CdSe-ZnS by hydrophilic from The thioglycolic acid (TGA), contains thiol covalentlyQD bind withreplaced. NH2 groups on protein and SiNPs. The hydrophobic ligands around surface of QD groups were replaced by hydrophilic ligand from thioglycolic acid (TGA), (-S). QD were replaced by hydrophilic ligand from thioglycolic acid (TGA), which contains thiol (-S)tofunctional groups attached at the surface of CdSe-ZnS. QD that will the electrostatic binding of the hydrophilic ligandsaffinity to the surface thiol (-S)

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