PSA detection electrochemical immunosensor based on MOF-235 nanomaterial adsorption aggregation signal amplification strategy

Abstract

Conventional electrochemical immunosensors use electroactive materials often suffer from leakage of electroactive materials and signal instability. To solve this problem, this paper proposes an electrochemical immunosensor based on MOF-235 adsorption aggregation signal amplification strategy for the sensitive detection of PSA. Methylene blue (MB) is a cationic dye with redox properties. It has electrochemical reversibility, high electron transfer rate and good biocompatibility. Therefore, it is often used as an electroactive substance in electrochemical immunosensors. However, the non-specificity and poor stability of MB will inevitably distort the diagnostic results and limit its application. In this experiment, MOF-235, a fluffy metal porous MOF material with two carboxyl groups has been prepared and it has a large specific surface area and good biocompatibility. Meanwhile, it can generate electrostatic attraction with the amino groups on MB, and firmly fix methylene blue on the MOF material, which can effectively prevent the signal leaks of MB during the test, and after being adsorbed, the reunion of MB can be controlled, which is conducive to electron transmission thus amplifying the electrical signal. The produced electrochemical immunosensor has good stability and repeatability, and the concentration of the analyte is directly linear with the magnitude of the electrical signal. Under optimum conditions, the proposed immunosensor shows a wide detection range from 10 pg·mL−1 to 1200 pg·mL−1 with a low detection limit of 3 pg·mL−1.