An UltraViolet Laser-Induced Fluorescence (UV-LIF) system to detect, identify and measure the concentration of biological agents in the environment: a preliminary study

Abstract

A: Detection and classification of biological agents are not easy, especially at an early stage of contamination and when more than one species is aerodispersed in the environment. This research aims at demonstrating the capability of UltraViolet Laser-Induced Fluorescence (UV-LIF) technique to detect, classify and measure the concentration of biological agents in aqueous samples, exploiting ubiquitous endogenous fluorophores. The incident radiation is a third harmonic Nd:YAG laser emitting at 355 nm. A spectrometer collects the fluorescence spectra that are subsequently analysed in order to achieve information about the classification and the concentration of each agent in the sample. The benefits of the UV-LIF combined with data analysis techniques concern the speed of the analysis, the limited costs for the equipment, and the possibility analyse the airflow without the need for sampling. A LIF-based system may find its applicability in different contexts (e.g. for the monitoring of HVAC systems in healthcare settings or in crowded places, such as schools or airports) allowing a fast and targeted response in the event of contamination. In this work, the experimental setup and the capability of the classification and measurement techniques will be discussed. The first measurements are shown to validate the potentialities of the LIF.

Photonics of human saliva: potential optical methods for the screening of abnormal health conditions and infections

“…Contactless, non-invasive photonic-based wearable sensors, which can provide rapid, and precise health information are also becoming common-place now (Yang and Gao 2019 ). Most important, photonics-based methods like Laser-induced fluorescence -LIF-, laser raman spectroscopy, photo thermal spectroscopy, hyperspectral imaging, laser-induced breakdown spectroscopy (LIBS), and reflectance spectroscopy are capable of remote, non-contact observation, and hence are highly suitable for identification of harmful or abnormal conditions in any kind of samples, including, clinical, environmental, and other (e.g., human and animal subjects) samples by remote, non-contact observations (Shameem et al 2017 ; Bishop et al 2019 ; Gabbarini et al 2019 ; Mandrile et al 2019 ; Nganou et al 2019 ; Yeh et al 2020 ).…”

An alternative SNR-based weighted-LSM algorithm to classify and measure the concentration of Biological Agents from Laser-Induced Fluorescence

“…The use of Laser-Induced Fluorescence (LIF) is largely investigated as optical technique to classify the Biological Agents (BAs) in a sample [1][2][3][4]. The fluorescence phenomena are electromagnetic emission originated by a molecule through its excitation with a specific wavelength [4,5].…”