Facile synthesis of highly active PtSnCoNi hierarchical dendritic nanowires greatly boosting signal amplification for ultrasensitive immunoassay of biomarker HER-2

Human epidermal growth factor receptor-2 (HER-2), a key biomarker in breast cancer, is critical for early diagnosis and prognosis evaluation. In this work, a label-free electrochemical immunosensor was developed for biomarker HER-2 detection based on PtSnCoNi hierarchical dendritic alloyed nanowires (PtSnCoNi HDNWs). These nanowires were synthesized via a co-reduction-triggered anisotropic growth strategy in oleylamine. Their dendritic structure, multiple compositions, and superior catalytic property for H₂O₂ reduction were rigorously characterized by multiple technologies. This biosensor demonstrated a broad linear range from 0.1 to 1,000,000 pg mL⁻¹ (R² = 0.9985) and a low detection limit of 0.068 pg mL⁻¹ (S/N = 3). It performed well in human serum samples, achieving recovery rates ranging from 103.8 % to 105.3 % and a relative standard deviation below 3.7 %, validating its clinical applicability. This work highlights the potential of advanced alloy materials in developing high-performance biosensors for early cancer biomarker detection.