Aptamer‑Based Magnetic Nanoprobe for Quantitative Measurement of Chloramphenicol in Milk through Portable Reader

Background: we described here an aptamer‑based magnetic nanoprobe for measuring the amount of chloramphenicol (cap) in milk. methods: the nanoprobe presented in this method consists of a magnetic nanoparticle conjugated to a specific cap aptamer. if the target is detected in the sample, the nanoprobe binds to it, and the aptamer forms a g‑quadruplex structure. this structure mimics the peroxidase activity in the presence of the hemin cofactor. if tetramethylbenzidine is added to the sample containing the nanoprobe, a blue color light is observed. after adding a stop reagent solution, the color produced is measured by a microplate reader and a portable meter. results: this study proves a 99% positive linear relationship between the microplate reader’s results and the portable meter results. conclusion: conjugation of the aptamer to magnetic nanoparticles and applying magnetic separation operations change the nanoprobe performance by 11% for both mentioned devices.