Evaluation of penicillin residues in milk by ELISA using aptamer bonded to gold nanoparticles

Healthy dairy products should be free of any substances that threaten human health. However, the use of antibiotics for the treatment of lactating animals can be a risk to human health, as their residues and metabolites can be transferred into milk. Various methods are used to ensure the purity of milk. In this study, a kit based on a specific penicillin aptamer bonded to gold nanoparticles was designed to measure penicillin in milk, and its measurement was performed using ELISA colorimetric method. After synthesis of gold nanoparticles, the molarity of gold nanoparticles was calculated by UV spectrophotometer, and its synthesis was confirmed by FTIR. Salt concentrations were also optimized to bind aptamer to gold nanoparticles. The gold nanoparticles were then bonded to the specific aptamer of penicillin, and the concentration of penicillin G in the milk sample was measured by a biosensor designed by ELISA. The choice of biosensor was also examined in the presence of similar antibiotics.