Dual-signaling and ultrasensitive detection for PCT based on the photoelectric and electrocatalytic hydrogen evolution signals of Pt/Mo-CoFeS.

Few study has been carried out on the construction of immunesensors utilized the photoelectric and catalytic signal of nanomaterial. Here, a dual-signal electrochemical immunosensor was constructed for procalcitonin (PCT) detection based on the excellent photoelectric and hydrogen evolution performance of molybdenum-doped cobalt-iron sulfur nanosheets modified by platinum nanoparticles (Pt/Mo-CoFeS). Due to the electronic structure regulation between Pt and Mo-CoFeS, Pt/Mo-CoFeS exhibits superior photoelectric and hydrogen evolution performance compared to single Mo-CoFeS, which improved the sensitivity of the electrochemical immunosensor. Furthermore, the presence of Pt improves surface area and biocompatibility, achieving more antibodies loading and signal amplification. The linear range of PCT detection are 0.002-20 ng mL-1 and 0.002-50 ng mL-1, the detection limits are 0.0015 and 0.0012 ng mL-1. In addition, this electrochemical immunosensor was applied to the PCT analysis in human serum samples with high recoveries. F-test and t-test show that there is no significant difference in the test results between the HER and photoelectric signals, the mutual verification between above two signals can effectively improve the accuracy of detection result.

CoFe-(oxy)hydroxide as a novel electrocatalytic tag in immunosensing for ultra-sensitive detection of procalcitonin based on the oxygen evolution reaction.

Nanomaterials play an important role in the fields of electrocatalysis and electrochemical immunosensor. As we all know, electrocatalytic oxygen evolution reaction (OER) can generate intensive current response under alkaline and even neutral conditions, and no by-products are produced. In recent years, OER based on non-noble metal nanocatalysts has become a research focus in the field of new energy, but there are few reports on using it as an electrocatalytic immunosensor label for biomolecule detection. In this study, we successfully synthesized CoFe-(oxy)hydroxide nanosheets through transforming CoFe prussian blue analogue (CoFe PBA). Based on the excellent OER activity of CoFe-(oxy)hydroxide in neutral solution, it was used as a new electrocatalytic marker for capturing procalcitonin (PCT) secondary antibody (Ab2). Meanwhile, gold nanoparticles (Au NPs) modified glassy carbon electrode (GCE) was utilized as immunosensor platform to immobilize PCT primary antibodies (Ab1). The linear range of the immunosensor for PCT detection is 0.0005 âˆ¼ 100 ng mL-1, and the detection limit is 0.33 pg mL-1. Furthermore, a high recovery was obtained when this proposed method was applied to analysis human serum samples. This work not only provides a new method for clinical analysis of PCT, but also extends the application of electrocatalytic OER.