Screen-Printed Nanohybrid Palladium-Based Electrodes for Fast and Simple Determination of Estradiol in Livestock

One of the main challenges in animal breeding systems is determining estradiol (E2) in livestock samples as simple and minimally invasive as possible, Thus, a nonenzymatic biosensor screen-printed electrode (SPE) was developed by modifying nanohybrid palladium nanoparticles (PdNPs), and carbon dots anchored on a nanosilica particle (PdNPs/C.dots/SiO₂), denominated SPE/PdNPs/C.dots/SiO₂, and successfully tested for the direct detection of estradiol in livestock samples. PdNPs were directly obtained by a one-step synthesis through carbon dot reduction. Hybrid nanomaterials were characterized by atomic force microscopy, high-resolution transmission electron microscopy, and electrochemical impedance. The combination of PdNPs with C.dots resulted in a nonenzymatic biosensor supported on a screen-printed platform with superior electrocatalytic properties regarding the oxidation of E2 when compared to unmodified sensors. Modifications in the working electrode resulted in high sensitivity toward E2 determination within a linear range from 0.005 to 14.0 μmol L^-1 with a limit of detection of 1.0 nmol L^-1. The recovery rate of E2 in bovine serum samples and urine samples ranged from 92 to 106%. Interference studies showed that peak current variation (Δ<i>i</i> _p) among all interferents evaluated and E2 did not exceed ±2%. The newly developed sensor stands out not only for its high sensitivity but also for its quick and simple way of production while also being disposable after analysis, providing a simple, sensitive, and practical approach for the determination of reproductive hormones in livestock.