Wine represents one of the most important business sectors in the Portuguese economy, for both internal and exportation market sectors. The development of fast, easy and cost-effective mycotoxins’ sensing systems, is of paramount importance to attest the quality of wine, through the detection of low concentrations of Ochratoxin-A and hence prevent diseases caused by its ingestion.
NANO4BIO aims the development of a new type of optical biodetection system, based on the Localized Surface Plasmon Resonance phenomenon that may be portable, easy to use, and able to detect low concentrations of biomolecules, namely mycotoxins commonly found in wine.
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The physical phenomenon to be explored is the use of the Localized Surface Plasmon Resonance (LSPR) effect, observed in noble metal nanoparticles (NPs). The LSPR effect amplifies electromagnetic fields near the resonance frequency, decaying rapidly with distance to the NP/dielectric interface.
The interaction between a nanocomposite film and (bio)molecular species causes detectable deviations in the LSPR band frequency, since nanoparticles are very sensitive to changes in the refractive index of the surrounding dielectric medium. TLSPR biosensors are thus expected to be able to detect very small amounts of biomolecules, such as specific mycotoxins, among which OTA, present in some food derivatives such as wine, stands out.
This project has as main research focus the doping/growing of gold NPs, in selected dielectric matrices (transition metal oxides/nitrides) and their functionalization as biosensors. Au NPs have unique properties, as they possess LSPR absorption bands in the visible zone of the electromagnetic spectrum, easily monitored with a spectrophotometer in transmittance mode (TLSPR). During this process, it becomes critical to monitor the formation process of the NPs, optimize the TLSPR bands and model the optical properties.
For the preparation of LSPR-based sensors, specific biomolecular recognition elements will be immobilized on the surface of the nanoplasmonic films to detect the target molecule. In the end, features such as specificity, sensitivity and detection limit will be evaluated on the developed high-resolution LSPR spectroscopy system and compared with those of conventional methods.
Due to the historical and economic importance of wine in Portugal, the project will place particular emphasis on the optimization of this methodology in wine samples. However, it is expected the application of this technology in other areas, namely: food safety, medical diagnosis or environmental quality.