Manipulating\nNear-Infrared Absorption via Engineering\nAnisotropic Plasmonic Spiky Au Nanocubes for the Highly Efficient\nDual-Response Immune Detection of T‑2 Toxin

Integrating specific immune recognition, a desirable\nextinction\ncoefficient, and conspicuous photothermal conversion ability into\na single-immune probe to enhance the analysis performance represents\nan appealing yet significantly challenging task. Herein, by delicately\nmanipulating the geometry of plasmonic nanoparticles from spherical\nto spiky, precise engineering approach-based spiky Au nanocubes (S-AuNCs)\nare employed to address this challenge, which fully exploits the plasmon\nresonance absorption-induced photothermal effect. The finite difference\ntime domain (FDTD) method was employed to computationally simulate\nthe electromagnetic and thermal fields while assessing the feasibility\nof regulating plasmon resonance for enhanced photothermal absorption.\nThe optimized noble photothermal agent simultaneously exhibits acceptable\nnear-infrared absorption (NIR), a significantly increased 808 nm extinction\ncoefficient (145 times higher than that of AuNPs), favorable antibody\ncoupling ability, and desirable photothermal conversion behavior.\nConsequently, the satisfactory performance of the S-AuNCs-guided colorimetric\nand photothermal lateral flow immunoassay (CPLFIA) is demonstrated\nfor the sensitive detection of T-2 toxin. In comparison to spherical\nAuNPs (35.2 pg/mL), the dual-mode detection sensitivity was enhanced\nby 1.862-fold and 5.18-fold, respectively, achieving limits of detection\nat 18.9 pg/mL (colorimetric mode) and 6.8 pg/mL (photothermal mode).\nTherefore, S-AuNCs-guided CPLFIA holds great potential in advancing\nfood mycotoxin safety control.