Label-free localized surface plasmon resonance (LSPR) biosensor, based on Au-Ag NPs embedded in TiO matrix, for detection of Ochratoxin-A (OTA) in wine.

Ochratoxin-A (OTA) is a widespread foodstuff contaminant with potential carcinogenic effects. Innovative sensing technologies that allow on-site and sensitive food screening can have a significant impact on food and environment safety. A novel and quantitative label-free LSPR-based biosensor was specifically designed for OTA detection, employing a portable LSPR spectroscopy sensing system for efficient on-site and cost-effective analysis.

New Parameter for Benchmarking Plasmonic Gas Sensors Demonstrated with Densely Packed Au Nanoparticle Layers.

Localized surface plasmon resonance (LSPR) gas sensitivity is introduced as a new parameter to evaluate the performance of plasmonic gas sensors. A model is proposed to consider the plasmonic sensors' surface sensitivity and plasmon decay length and correlate the LSPR response, measured upon gas exchange, with an equivalent refractive index change consistent with adsorbed gas layers. To demonstrate the applicability of this new parameter, ellipsoidal gold nanoparticles (NPs) arranged in densely packed hexagonal lattices were fabricated.

Enhancing the Extinction Efficiency and Plasmonic Response of Bimetallic Nanoparticles of Au-Ag in Robust Thin Film Sensing Platforms.

The extinction efficiency of noble metal nanoparticles (NPs), namely gold (Au) and silver (Ag), are dependent on their size and surrounding dielectric. Exploiting the Localized Surface Plasmon Resonance (LSPR) phenomenon, the composition and structure of the NPs might be tailored to achieve a configuration that optimizes their response (sensitivity) to environmental changes. This can be done by preparing a bimetallic system, benefiting from the chemical stability of Au NPs and the higher scattering efficiency of Ag NPs.

Recent advances in nanomaterial-based optical biosensors for food safety applications: Ochratoxin-A detection, as case study.

Global population growth tremendously impacts the global food industry, endangering food safety and quality. Mycotoxins, particularly Ochratoxin-A (OTA), emerge as a food chain production threat, since it is produced by fungus that contaminates different food species and products. Beyond this, OTA exhibits a possible human toxicological risk that can lead to carcinogenic and neurological diseases.

Chitosan Micro-Membranes with Integrated Gold Nanoparticles as an LSPR-Based Sensing Platform.

Currently, there is an increasing need to develop highly sensitive plasmonic sensors able to provide good biocompatibility, flexibility, and optical stability to detect low levels of analytes in biological media. In this study, gold nanoparticles (Au NPs) were dispersed into chitosan membranes by spin coating. It has been demonstrated that these membranes are particularly stable and can be successfully employed as versatile plasmonic platforms for molecular sensing.

Optimization of Au:CuO Thin Films by Plasma Surface Modification for High-Resolution LSPR Gas Sensing at Room Temperature.

In this study, thin films composed of gold nanoparticles embedded in a copper oxide matrix (Au:CuO), manifesting Localized Surface Plasmon Resonance (LSPR) behavior, were produced by reactive DC magnetron sputtering and post-deposition in-air annealing. The effect of low-power Ar plasma etching on the surface properties of the plasmonic thin films was studied, envisaging its optimization as gas sensors. Thus, this work pretends to attain the maximum sensing response of the thin film system and to demonstrate its potential as a gas sensor.

Immobilization of Streptavidin on a Plasmonic Au-TiO Thin Film towards an LSPR Biosensing Platform.

Optical biosensors based on localized surface plasmon resonance (LSPR) are the future of label-free detection methods. This work reports the development of plasmonic thin films, containing Au nanoparticles dispersed in a TiO matrix, as platforms for LSPR biosensors. Post-deposition treatments were employed, namely annealing at 400 °C, to develop an LSPR band, and Ar plasma, to improve the sensitivity of the Au-TiO thin film.

Development of label-free plasmonic Au-TiO thin film immunosensor devices.

This work reports on the development of a label-free immunosensor technology, based on nanoplasmonic Au-TiO thin films. The Au-TiO thin films were prepared by cost-effective reactive DC magnetron sputtering, followed by a thermal annealing procedure. The latter promoted the growth of the Au nanoparticles throughout the TiO matrix and induced some morphological changes, which are the base for the immunosensor device functionality.