fabrication of electrochemical aptasensor modified by nanoparticles to ultrasensitive detection of tetracycline in milk

Abstract: using antibacterial drugs plays an important role in the treatment of human diseases and veterinary medicine for more than a hundred years. nowadays, excessive use of antibiotics resulted in antimicrobial resistance (amr), and antibiotic resistance has become a serious public health problem.[1, 2] among all antibacterial drugs, tetracycline (tet) has been commonly used in the treatment of animal and human diseases due to its good bactericidal properties and low cost [3]. therefore, development of a selective, and sensitive technique is urgent to detect tetracycline in food samples [4] in this study, an ultrasensitive and selective label-free electrochemical aptasensor based on a glassy carbon electrode (gce), modified by nano particles and aptamer single strand was fabricated for detection of tetracycline (tet) trace values in food samples.the stepwise modification process of the aptasensor fabrication was characterized by cv, dpv and eis techniques. the optimization of the instrumental parameters and experimental conditions (ph, incubation time and concentration of nanoparticles, aptamer and tet) was performed. under optimized conditions, the developed aptasensor was used to determine the tetracycline concentration using differential pulse voltammetry (dpv). this biosensor was achieved a good dynamic linear range (10-16–10-10 m) and a low detection limit (1.079×10-17 m). fabricated aptasensor showed excellent stability, selectivity, repeatability (rsd = 1.58%), reproducibility (rsd = 3.40%) and accuracy. finally, this aptasensor was applied to the determination of tetracycline in milk.