Establishment of electrical immunosensor for the detection of nuclear matrix protein-22

Abstract

Objective A label-free electrochemical immunosensor was developed for the detection of nuclear matrix protein-22 (NMP22) as a biomarker of bladder cancer. Methods The study was based on the establishment and validation of the methodology. Urine samples were collected from 20 patients with bladder cancer and 20 controls in the affiliated Hongqi hospital of Mudanjiang medical university from September in 2017 to July in 2019 to validate the developed method. A screen-printed electrode (SPE) was modified with a film of a composite made from the reduced graphene oxide-tetraethylene pentamine (rGO-TEPA) immobilized Zn-based-Metal-organic frameworks deposited with Au nanoparticles (rGO-TEPA@Au-ZIF8). Primary antibody against NMP22 was immobilized on the Au nanoparticles on the surface of the modified SPE, which then was blocked with bovine serum albumin to elimiate nonspecific binding sites. The process of the construction of the proposed sensorwas characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Differential pulse voltammetry was used to evaluate the linear range, recovery, precision, selectivity and stability. The data were analyzed by Mann-Whitney U test. Results Under optimal conditions, the immunosensor exhibited a linear range of 0.01-1000 ng/mlwith a detection limit of 3.33 pg/ml (S/N=3) and a standard recovery of 97.65%-107.05%. The levels of NMP22 in urine samples from patients with bladder cancer [66.03 (4.34, 91.74)]ng/ml determined by the proposed sensor were significantly higher than those of controls 0.54(0.06, 8.84) ng/ml(P=0.001). Conclusion The immunosensor can achieve sensitive, rapid and acucurate detection of NMP22, and has potential application prospects in monitoring tumor markers. Key words: Urinary bladder neoplasms; Nuclear proteins; Biosensing techniques; Electrochemical techniques; Immunoassay; Graphite; Polyamines; Biomarkers, tumor