Self-supported PtPdMnCoFe high-entropy alloy with nanochain-like internetworks for ultrasensitive electrochemical immunoassay of biomarker

High-entropy nanomaterials are regarded as the new research hotspots for their intriguing "cocktail effect". Herein, self-supported PtPdMnCoFe high-entropy alloy with nanochain-like internetworks (PtPdMnCoFe HEAINN) were synthesized by a one-pot co-reduction method, where newly-generated H2 bubbles served as dynamic template, as identified by a series of characterizations. The high-entropy architecture was certificated effectiveness for reduction of H2O2, which was explored as signal amplifier to develop a novel label-free electrochemical amperometric immunosensor for ultrasensitive determination of biomarker neuron-specific enolase (NSE). In the optimized analytical surroundings, the as-fabricated sensor showed a broad linear range of 0.1 pg mL-1 to 200 ng mL-1 for immunoassay of NSE with a low limit of detection (LOD = 0.0036 pg mL-1, S/N = 3), coupled by its quantification in human serum samples with satisfactory results. This work provides valuable guidance for potential applications of high-entropy alloyed materials in biosensors and immunoanalysis.