Highly sensitive electrochemical determination of neutrophil gelatinase-associated lipocalin for acute kidney injury.

A label-free electrochemical immunosensor for the detection of neutrophil gelatinase-associated lipocalin (NGAL) is developed by the immobilization of rabbit polygonal lipocalin-2 antibody on gold nanoparticles attached on generation-1polyamidoamine (PAMAM) dendrimer (LA2/AuNPs/PAMAM)-modified gold electrode. The modification procedure was characterized by UV-vis, surface enhanced Raman spectroscopy and field-emission scanning electron microscopy techniques. The detection of NGAL is based on the enhancement of oxidation current on the modified electrodes upon the antigen-antibody interaction. The electrochemical immunosensor exhibited high sensitivity (1 ng mL(-1) (280 pM) based on the signal-to-noise ratio 3), wide linear range (50-250 ng mL(-1)) and long-term stability. The reliability of the developed immunosensor was investigated by the detection of NGAL in both blood serum and urine samples.