Construction of electrochemical aptasensors with Ag(I) metal−organic frameworks toward high-efficient detection of ultra-trace penicillin

Two novel silver-based metal − organic frameworks (MOFs) have been successfully designed and synthesized by coordination assembly of tri(pyridin-4-yl)amine (TPA) and Ag(I) salts with different anions (SiF62− vs. CH3SO3−). Both MOFs show excellent physicochemical stability and superior electrochemical activity. It is the first time to implement Ag(I)-MOFs to fabricate high-efficient aptasensors to detect ultra-trace penicillin by electrochemical method. Remarkably, the Ag2SiF6-MOF-based biosensor shows ultra-high selectivity toward penicillin in the presence of other antibiotic interferences, which also exhibits the lowest detection limit of 0.849 pg mL−1 among all reported sensing materials, in the concentration range from 0.001 to 0.5 ng mL−1. Moreover, the fabricated aptasensor with good repeatability and high stability can effectively monitor penicillin in real milk sample. Interestingly, the isostructrual nature of two MOFs firstly illustrates the critical role of anion in constructing MOFs-based aptasensors. This work establishes a promising approach to design and modulate MOFs-based aptasensors for rapid and convenient detection of ultra-trace targets.