▎ 摘　　要

Herein, we report the fabrication of aptamer probe for ultrasensitive detection of penicillin based on unique nanocomposite material consist of graphene and iron oxide (magnetite) (GR-Fe3O4) and multi-walled carbon nanotubes and iron oxide (MWCNTs-Fe3O4 ) with nanoporous platinum and titanium (NP-PtTi) alloy. The prepared new nanocomposite material provide a signal amplification and immobilization strategy and hence significantly contribute in the fabrication of ultrahigh sensitive label-free penicillin aptasensor. The detailed studies confirmed that the prepared newly composite i.e. nanoporous PtTi/GR-Fe3O4/MWCNT-Fe3O4 exhibited improved synergistic effect compared with any other single material. The developed biosensor demonstrates ideal stability and reproducibility with high selectivity. The observed linear range of the as-prepared aptasensor was from 0.05 to 100 ng mL(-1) with an ultra-low detection limit of 25.3 pg mL(-1). Based on the good sensing performance, the constructed electrochemical aptasensor showed potential practical application in the quantitative analysis of penicillin.