Pietro Bertolotti | Searcharxiv

arXiv2026

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

Bioresponsive optical materials that transduce nanoscale biointerface events into measurable spectral signals are of growing interest for sensing and antiviral technologies Here we show that a Tamm plasmon TP device consisting of a SiOTiO distributed Bragg reflector capped with a nanostructured silver layer exhibits a selective and structure dependent response to SARSCoV2 virus like particles VLPs Upon VLP exposure the conventional wavelength shift delta lambda of the TP resonance is minimal whereas the resonance depth undergoes a systematic attenuation To capture both spectral and amplitude variations we introduce a displacement angle alpha defined from the translation vector of the Tamm dip before and after exposure The angle alpha increases monotonically with VLP concentration and enables a limit of detection of 13 ng per mL Control experiments with polystyrene nanoparticles of similar size and with heat denatured VLPs yield negligible changes indicating sensitivity to the native conformational state of viral surface proteins rather than to generic nanoparticle morphology or bulk refractive index effects These results establish Tamm plasmon structures as promising bioresponsive platforms for label free detection and for probing structure dependent virus material interactions.

physics.optics↗

arXiv2022

Tamm Plasmon Resonance as Optical Fingerprint of Silver/Bacteria Interaction

Incorporation of responsive elements into photonic crystals is an effective strategy for building up active optical components to be used as sensors, actuators and modulators. In these regards, Tamm Plasmon (TP) modes have arisen recently as powerful optical tools for the manipulation of light-matter interaction and for building sensors/actuators. These emerge at the interface between a dielectric mirror and a plasmonic layer and, interestingly, can be excited at normal incidence angle with relatively high quality factors. Although its field is located at the interface between the dielectric mirror and the metal, recent studies have demonstrated that corrugation at the nanoscale permits to access the TP mode from the outside, opening new exciting perspectives for many real-life applications. Here, we show that the TP resonance obtained by capping a distributed Bragg reflector with a nanostructured layer of silver is sensitive to the presence of bacteria. We observed that nanoscale corrugation is essential for accessing the TP field, while the well-known bio-responsivity of silver nanostructures renders such a localised mode sensible to the presence of Escherichia Coli. Electrodoping experiments confirm the pivotal role of nanostructuration, as well as strengthening our hypothesis that the modifications of the TP mode upon exposure to bacteria are related to the accumulation of negative charge due to the bacterial-driven removal of Ag+ ions from its lattice. Finally, we devised a case study in which we disentangled optically the presence of proliferative and non-proliferative bacteria using the TP resonance as a read-out, thus making these devices as promising simple all-optical probes for bacterial metabolic activity, including their response against drugs and antibiotics.

physics.optics↗