A joint action of aptamers and gold nanoparticles chemically trapped on a glassy carbon support for the electrochemical sensing of ofloxacin

Abstract

A joint action of ssDNA aptamers and electrochemistry is a key element in developing successful biosensing platforms, since aptamers are capable of binding various targets with high specificity, and electrochemistry is one of the most sensitive techniques for on-site detections. A continuous search for improved immobilization and sensing strategies of aptamers on transducer surfaces resulted in the strategy presented in this article. The strategy is based on the covalent attachment of gold nanoparticles on the surface of glassy carbon electrodes through sulfhydryl-terminated monolayer, acting as a glue to connect AuNPs on the electrode. The covalently attached gold nanoparticles modified glassy carbon electrodes have been applied for the efficient immobilization of thiolated ssDNA probes, with a surface coverage of about 8.54×10 13 molecules cm −2 which was 7-fold higher than that on the electrochemically deposited gold nanoparticles. Consequently, improved sensitivity, good reproducibility and stability are achieved for electrochemical aptasensor. Combined with the high affinity and specificity of an aptamer, a simple, novel, rapid, sensitive and label-free electrochemical aptasensor was successfully fabricated for ofloxacin (OFL) detection. The linear dynamic range of the sensor varies between 5×10 -8 to 2×10 -5 M OFL with a detection limit of 1×10 -9 M OFL. A potential application in environmental monitoring was demonstrated by using this sensing strategy for the determination of OFL in (experimentally spiked) real samples such as tap water and effluent of sewage treatment plant. The proposed nanoaptasensor combines the advantages of the covalent attachment of neatly arranged AuNPs (enlarged active surface area and strengthened electrochemical signal) and the elimination of labels for the amplified detection of OFL, with the covalent attachment of highly specific aptamers to the surface of the modified electrode.

Aptamer-Based Biosensors for Antibiotic Detection: A Review

“…Ofloxacin ( Figure 6 d) is a second-generation fluoroquinolone, used in bacterial infections of the respiratory tract and the gastrointestinal tract [ 184 ].…”

“…In 2017 Pilehvar et al [ 184 ] developed a rapid, stable, and sensitive label-free electrochemical aptasensor for ofloxacin detection based on the immobilization of the specific aptamer on AuNPs. The most important data of the two aptasensors are summarized in Table 13 .…”

Aptamer-based Biosensors for Antibiotic Detection: A Review

“…Ofloxacin (Figure 6(d)) is a second-generation fluoroquinolone, used in bacterial infections of the respiratory tract and the gastrointestinal tract [180].…”

“…In 2017 Pilehvar et al [180] developed a rapid and sensitive label-free electrochemical aptasensor for ofloxacin detection. For the immobilization of the specific aptamer a covalently attached AuNPs modified GCE was used.…”

Electrochemical Peptide-Based Sensors for Foodborne Pathogens Detection

“…The majority of the electrochemical sensors are based on modified electrodes with different types of molecules that ensure the specificity toward a designated target. Enzymes [ 6 ], cells [ 7 ], antibodies [ 8 ], aptamers [ 9 , 10 ], antigens [ 11 ], and peptides [ 12 ] are some of the bio-compounds that can be immobilized onto the electrodes’ surface in order to detect a single compound from complex matrices.…”