Visible light photoelectrochemical aptasensor for chloramphenicol by using a TiO2 nanorod array sensitized with Eu(III)-doped CdS quantum dots

Abstract

A visible-light driven photoelectrochemical (PEC) aptasensor is described that is capable of detecting chloramphenicol (CAP). It is based on the use of a TiO based nanorod array (NRA) sensitized with Eu(III)-doped CdS quantum dots. The NRA absorbs visible-light and while strongly depressing the recombination of photogenerated charges, thereby improving photo-to-current conversion efficiency. The introduction of Eu(III) ions promotes the charge transformation and utilization, and this results in a further increase of photocurrent. The NRA was employed as the photoactive material for the fabrication of a PEC aptasensor. CAP-binding aptamers were immobilized on a fluorine-doped tin oxide (FTO) electrode that was modified with the NRA. The aptasensor was applied to the determination of CAP by monitoring the decrease in photocurrent (at a typical voltage of 0 V) that is caused by the formation of the aptamer-CAP complex. Under optimal conditions, the response is linear in the 1.0 pM to 3.0 nM CAP concentration range, with a detection limit of 0.36 pM (at S/N = 3). The method was applied to the determination of CAP in spiked milk samples where it gave satisfactory results. Graphical abstract Schematic presentation of the fabrication of a visible-light driven photoelectrochemical aptasensor based on the use of a TiO nanorod array sensitized with Eu(III)-doped CdS quantum dots. It was applied to the determination of chloramphenicol with good selectivity and high sensitivity. TiO NRA: TiO nanorod array; FTO: fluorine-doped tin oxide; CdS:Eu QDs: Eu(III)-doped CdS quantum dots; BSA: bovine serum albumin; CAP: chloramphenicol.

Label-Free Electrochemical Aptasensor for Sensitive Detection of Malachite Green Based on Au Nanoparticle/Graphene Quantum Dots/Tungsten Disulfide Nanocomposites

“…After immobilizing the aptamer on the surface of AuNPs/GQDs-WS 2 /GCE, a drastically increased R et value was observed (curve c), implying successful assembly of aptamers of MG on the electrode surface. This increase in resistance is due to the electrostatic repulsion between the negatively charged redox probe and phosphate backbone of the aptamer [33]. Subsequently, the R et value significantly increased in curve d because the immobilized MCH hindered interfacial electron transfer.…”

Electrochemical Aptasensors for Antibiotics Detection: Recent Achievements and Applications for Monitoring Food Safety

“…In the latter case, QDs mostly consist of carbon nanomaterials: QDs do not worsen the electroconductivity of the surface layer but improve the surface density of the aptamers on the electrode interface and, hence, increase the signal-to-noise ratio by partial suppression of undesired adsorption of interferences. It seems obvious that the use of QDs was inspired by the undoubted advantages of their applications in optical sensing systems including photochemical sensors [ 197 , 239 , 249 , 256 , 259 ]. More common CdS QDs are also used as passive carriers for aptamers [ 208 ] or sources of Cd ion detection using DPV [ 181 , 182 , 198 ].…”

Aptamer-Based Biosensors for Antibiotic Detection: A Review

“…Based on the sensor principle to develop a electrochemiluminescent aptasensor for the detection of chloramphenicol [ 149 , 161 , 162 ], a triple-amplification assay using polymer enzyme-linked nanotracers/Exonuclease-assisted target recycling method [ 154 ] and TiO 2 -based nanorod assay sensitized with Eu(III)-doped CdS QDs as the photoactive material [ 163 ] were designed with a detection limit of 0.034 and 0.36 pM towards chloramphenicol, respectively.…”