Rational construction of a zirconium–organic framework@MXene nanocomposite for constructing a sensitive electrochemical aptasensor.

A PCN-222@MXene-based electrochemical aptasensor is fabricated to detect trace oxytetracycline via differential pulse voltammetry. The electrochemical aptasensor has good stability, fine reproducibility, and high selectivity. [Display omitted] • PCN-222 is assembled with MXene nanolayers to form PCN-222@MXene composites. • The electrochemical aptasensor can sensitively detect trace oxytetracycline. • Differential pulse voltammetry is used as the sensing method in this work. Metal–organic frameworks (MOFs) have received lots of attention in the field of electrochemical aptasensors in recent years, but most MOFs have poor conductivity to limit their electrochemical detection performance. Hence, it is still a great challenge to construct excellent MOF-based composites for fabricating outstanding electrochemical aptasensors. In this work, a zirconium–organic framework (PCN-222) is assembled with the MXene nanosheet to obtain a PCN-222@MXene nanocomposite. Due to copious Zr(IV) sites and abound mesopores of PCN-222, and the good conductivity of MXene nanosheets, the PCN-222@MXene nanocomposite is a good functional material to immobilize aptamers. Oxytetracycline (OTC), as an analytic mode, has been widely used in various applications, but the residual OTC brings a series of health and environmental problems. Excitingly, the electrochemical aptasensor based on PCN-222@MXene exhibits more outstanding sensing performance toward OTC via differential pulse voltammetry than many reported sensors, including low limitation of detection, high selectivity, available stability and reproducibility. [ABSTRACT FROM AUTHOR]