Aptamer‐Based Colorimetric Detection of Oxytetracycline by a LSPR‐Based Assay of Gold Nanorods in Honey Sample**

Abstract

AbstractOxytetracycline (OTC) as the frequently applied antibiotics present in human and animal diets and its residue may results to various toxic effects. So, there is a crucial need for developing sensitive method for detection of OTC. Aptamer‐based biosensors (aptasensors) are frequently used in recent applied detection strategies with high affinity and specificity. In the present study, a colorimetric aptasensor was developed for detection of oxytetracycline (OTC) based on aggregation of aptamer functionalized AuNRs. The synthesized AuNRs were characterized and functionalized with specific DNA oligonucleotide as the aptamer to generate an optical signal after binding to the OTC antibiotic. The sensitivity of optical changes in spectroscopic analysis was improved under ambient temperature that resulted in aptamer folded structure and subsequent aggregation state of AuNRs. The longitudinal surface plasmon resonance (LSPR) of AuNRs was decreased in the linear range of applied OTC concentration from 0.1 nM to 100 nM with a detection limit of 0.04 nM. The proposed method was facile and showed sensitive and selective results, that would be consider as an alternative and efficient approach toward rapid detection of OTC.