Bioinspired urchin-like AuMnCu nanoreactors: Integrating tip-enhanced electric fields with alloy-tuned interfacial...

Alloying-tuned electronic structure engineering offers a promising avenue to enhance the interfacial thermoelectric-phonon coupling effects of multifunctional nanomaterials and further improve the analytical performance, especially in the photothermal sensing performance combined with morphology engineering. A stable interface electronic configuration is formed by changing the electronic structure and enhancing the interaction between the metal and electrons. Escherichia coli 0157: H7, as a foodborne pathogenic bacterium posing a serious threat to human health, urgently needs to go beyond the colorimetric single detection and achieve a sensitive and rapid dual mechanism. The electronic structure of nanomaterial engineering certainly sets up a bridge for this purpose.

Herein, we developed an alloy-engineered interfacial electronic modulation strategy to synthesize trimetallic AuMnCu nanoparticles (AMC) via one-step ultrasonication. The biomimetic urchin-like nanostructure facilitates molecular-level antibody-mediated bacterial capture while exhibiting synergistic tip-enhanced plasmonic resonance and MnCu alloy-driven hot electron-phonon coupling. Finite element method (FEM) simulations verify these effects, establish built-in electric fields that broaden AMC's optical absorption in immunochromatographic assays (ICA), simultaneously enhancing colorimetric signal intensity, photothermal conversion efficiency, stability, and dispersibility. The detection limits of colorimetric and photothermal modes are 10³ and 10² CFU mL^-1 for Escherichia coli O157:H7 (E. coli O157:H7) detection, respectively, representing a 1000-fold improvement in sensitivity compared to conventional AuNPs-ICA (10⁵ CFU mL^-1). Meanwhile, the recoveries in the complex substrates of skim milk and apple juice are 85.0 %-106.2 %.

These results establish alloying-mediated electronic structure optimization as an effective strategy for enhancing ICA performance through improved thermoelectric-phonon coupling. Furthermore, it provides a field-deployable point-of-care (POC) tool for detecting foodborne pathogen contamination in complex matrices, and reveals the deep coupling of "material genes" and "target pathogenic bacteria" to achieve more accurate manipulation and provide efficient and technology-enabled solutions to global challenges such as food safety and public health crises.