AuNP Tetramer-Based Aptasensor for SERS Sensing of Oxytetracycline

A novel aptasensor was described and employed for ultrasensitive determination of the antibacterial agent oxytetracycline (OTC). This method was based on gold nanoparticle (AuNP) tetramers and surface-enhanced Raman spectroscopy (SERS). Under optimal conditions, in the range of 0.01–250 ng/mL, the concentration of OTC exhibited good linear relationship ( R 2  = 0.9948) with changed SERS signal intensity. In addition, the applicability of the novel aptasensor was validated by detecting different concentrations of OTC spiked in milk samples. With its satisfactory performances, this aptasensor is perceived to be a promising candidate for determining OTC in food products. This assay could also be extended for the analysis of other targets (pathogens or harmful substances) in food products by using corresponding DNA sequences.