Novel electrogravimetric biosensors for the ultrasensitive detection of plasma matrix metalloproteinase-2 considered a potential tumor biomarker

In this study, we developed novel, simple gravimetric and voltammetric sensors for the ultrasensitive detection of active matrix metalloproteinase (MMP)-2 in plasma. The developed sensors are cost-effective, require a very less amount of reagents, and are time-saving. They detect MMP-2 based on antigen–antibody recognition and its ability to cleave glycine-leucine peptide bond. The three-dimensional bioplatform of the sensors consisted of a cationic polyethyleneimine (PEI) polymer that facilitated robust immobilization of the dipeptide labeled with anthraquinone (AQ), or antibody molecules in appropriate density, which was crucial for biosensing. Detection was performed using quartz crystal microbalance with dissipation and voltammetry. The results showed that the developed sensors were characterized by high stability, wide analytical range (2.0 pg mL−1 to 5.0 μg mL−1), and low detection limit (ca. 10 fg mL−1). They also exhibited excellent efficiency in the determination of active MMP-2 in real samples, such as blood plasma. The developed sensors may hold great promise for the early diagnosis of cancers.