A new fluorescence sensor developed with polydopamine nanospheres for the detection of anti-PLA2R antibody biomarkers of idiopathic membranous nephropathy.

Anti-PLA2R antibody is only expressed in podocytes from patients with idiopathic membranous nephropathy (IMN). The detection of anti-PLA2R antibody in serum is therefore able to obtain essential information for rapid diagnosis and evaluation of the disease activity of IMN. In the present study, a polydopamine nanosphere-based fluorescent sensor was constructed for direct detection of anti-PLA2R antibodies in human serum. In this sensing system, the double-stranded DNA was phosphorylated under the action of anti-PLA2R antibody and the single-stranded DNA was cut by exonuclease. The single-stranded DNA was then adsorbed on polydopamine microspheres. The fluorescent groups labeled on the DNA were quenched, and the concentration of anti-PLA2R antibody was detected quantitatively by measuring the fluorescence signal changes before and after the reaction. The experimental results show that the method has a good linear detection range between 0.05 and 10 μg/mL for anti-PLA2R antibody and the detection limit is 0.02 μg/mL. Graphical abstract.