Electrochemical immunosensor for the determination of prolactin in saliva and breast milk

An electrochemical immunosensor for the fast, sensitive, and selective determination of salivary prolactin (PRL) is reported in this work. The developed methodology uses a sandwich-type immunoassay implemented on magnetic microparticles (MBs) functionalized with neutravidin (NA-MBs) where the capture antibody was immobilized. The resulting immunocomplexes were placed onto a screen-printed carbon electrode (SPCE) and the target hormone quantification was made by amperometry at − 0.20 V (vs. Ag pseudo-reference electrode) using the HQ/H2O2 system as electron transfer mediator and enzyme substrate. The developed immunosensor allows the determination of PRL in a linear range between 1.1 and 100 ng mL−1 (R2 = 0.996) with a limit of detection (LOD) value of 0.32 ng mL−1 PRL, and shows an excellent selectivity. The whole assay protocol takes 46 min. The immunosensor was able to determine PRL in saliva with results in agreement with those provided by ELISA method. In addition, the developed immunosensor was applied to the determination of PRL in breast milk.