Novel nanoarchitecture of Co-MOF-on-TPN-COF hybrid: Ultralowly sensitive bioplatform of electrochemical aptasensor toward ampicillin

Owning to the misuse of the antibiotics in animal husbandry and agriculture, it is highly urgent to determine the quantification of antibiotics in biological systems by the simple, sensitive, and fast method. In this work, a novel nanoarchitecture of Co-based metal-organic frameworks (Co-MOF) and terephthalonitrile-based covalent organic framework (TPN-COF) was synthesized (represented by [email protected]), followed by the exploitation as the bioplatform of non-label aptasensor for detecting the most frequently used β-lactam antibiotics, ampicillin (AMP). The new porous hybrid material of [email protected] was synthesized by adding the as-prepared TPN-COF into the Co-MOF preparation system. The multilayered [email protected] nanosheets exhibit a high specific surface area (52.64 m2 g−1), nitrogen-rich groups and excellent electrochemical activity. As a result, large amounts of aptamer strands can be bound over the [email protected] nanosheets owning to the strong π–π stacking and hydrogen bonds. When detecting AMP by the electrochemical impedance spectroscopy, the fabricated [email protected] aptasensor exhibits an ultra-low detection limit of 0.217 fg mL−1 within the AMP concentration from 1.0 fg mL−1 to 2.0 ng mL−1, which was superior to those previously reported in literatures. In addition, this proposed aptasensor also shows high selectivity, good reproducibility and stability, acceptable regenerability, and favorable applicability in human serum, river water and milk. Therefore, the proposed [email protected] aptasensor has a great promise to be applied as a powerful tool in the fields of food safety.