A novel nano copper complex: potentiometry, DFT and application as a cancer prostatic biomarker for the ultrasensitive detection of human PSA

Abstract

Worldwide, prostate cancer is considered to be one of the three most commonly occurring cancers amongst the male population. Clinically, early detection of diverse forms of cancer before they spread and become incurable plays an important role in treatment strategy. Therefore, the development of fast, accurate, sensitive, and low-cost analytical methodologies and techniques for the detection of cancer biomarkers is an attractive research area for scientists globally. Herein, a Schiff base ligand (A1) was prepared via the refluxing of 3-aminobenzoic acid with 1,2-phenylenediamine. After that, a nano Cu complex (N1) was synthesized by reacting A1 with copper chloride. The produced A1 and N1 were characterized using several techniques to determine their physicochemical properties. A density functional theory study was carried out to rationalize the experimental work and support the obtained results. Moreover, the nano Cu complex (N1) was used for the fabrication of a potentiometric membrane biosensor for the early detection of the prostate-specific antigen (PSA). The results reveal that the electrode displays a stable Nernstian response of 29.26 ± 0.87 mV per decade for PSA in a linear dynamic range of 5.0 pg mL⁻¹–10.0 ng mL⁻¹, in a pH range of 6.5–9.2, with a short response time of 25 ± 5 s. The lifetime was between 5–7 weeks under different storage conditions. The detection (LOD) and quantification (LOQ) limits were 0.098 and 0.297 pg mL⁻¹, respectively. The presence of different interfering species on the potentiometric biosensor response against PSA was investigated. The sensing mechanism of N1 toward PSA and the applicability of the developed electrode for the screening and quantification of PSA in real serum samples were also studied.