Functionalized magnetic nanoparticles for electrochemical magneto biosensing of PSMA cancer biomarker

Abstract

A novel platform on which anti-prostate specific membrane antigen (PSMA) antibodies were immobilized on the core–shell structure of iron oxide (Fe₃O₄)/6-phosphonohexanoic acid (6Pha) nanoparticles was developed for the specific detection of PSMA. The Fe₃O₄@SiO₂@6Pha nanoparticles were selected as an immune sensing platform, and external magnetic force provided separation of the target PSMA antigen in biological samples. The core–shell Fe₃O₄@SiO₂@6Pha nanoparticles conjugated with anti-PSMA antibodies were utilized for PSMA concentration measurement. The analysis strategy was based on the direct binding of anti-PSMA antibodies to the target PSMA antigens. Different electrochemical analysis approaches were utilized to characterize the biosensing system. The differences in impedimetric signals before and after interaction with PSMA antigens were associated directly with the PSMA concentration. Under optimized conditions, the linear range of 7.5–1250 pg mL⁻¹, the detection limit of 2.21 pg mL⁻¹, and the quantification limit of 7.36 pg mL⁻¹ were obtained. The applicability of the immunosensor was tested on diluted human serum samples, and satisfactory results were obtained. The results illustrate that a reliable, robust, selective, and simple detection strategy was developed for further clinical diagnosis.