Tamm Plasmon Resonance Responsiveness to SARS‐CoV‐2 Virus‐Like Particles

ABSTRACT Bioresponsive optical materials that convert nanoscale biointerface events into measurable spectral signals are of growing interest for sensing and antiviral applications. Here, we show that a Tamm plasmon (TP) device, consisting of a SiO 2 /TiO 2 distributed Bragg reflector capped with nanostructured silver, responds to SARS‐CoV‐2 virus‐like particles (VLPs) in a concentration‐dependent manner without selective functionalization. Upon VLP exposure, the conventional wavelength shift ( Δλ ) of the TP resonance is small (∼4 nm), whereas the resonance depth decreases systematically, by about 60% at 10 ng/mL VLP. To capture both spectral and amplitude changes, we define a displacement angle, α, from the translation vector of the Tamm dip before and after exposure. α increases monotonically with VLP concentration, from 1.3° ± 2° at 0 ng/mL to 9.7° ± 0.5° at 10 ng/mL. Control experiments with similarly sized polystyrene nanoparticles and heat‐denatured VLPs yield negligible changes (0.7° ± 1.9° and −0.7° ± 4°, respectively), indicating sensitivity to the native conformational state of viral surface proteins rather than generic nanoparticle morphology or bulk refractive‐index effects. These results establish TP structures as promising label‐free platforms for detection and probing structure‐dependent virus‐material interactions.