Development of a sustainable biosensor to detect respiratory infectious diseases

Abstract

The Covid-19 pandemic brought the need to use social masks to prevent the spread of the SARS-CoV-2 virus. However, no reliable and fast method were yet established to detect viral particles and to improve the protective ability of social masks.

Through color changes, colorimetric biosensors can be used as a rapid and easily approach to detect virus. Gold nanoparticles (AuNP) are known to have excellent optical properties and huge research potential.

The new SARS-CoV-2 has the ability of entering human body cells, namely through a second pathway of entry – the sialic acid (SA) receptor.

In order to respond to the emergency and to contribute to the diminishing of the spread of SAR-CoV-2, we developed a colorimetric biosensor based on the functionalization AuNP by sialic acid (SA) (SA-AuNP), as a new and effective textile coating layer, to provide a direct indication of the protective capacity of social masks.

To do that, AuNPs (10 nm) were functionalized with SA (SA-AuNP), in three different concentrations (50-50, 30-70 and 20-80, respectively) to select the optimal concentration for respiratory virus detection. Fourier-transform infrared spectroscopy (FTIR) and Scanning Electron Microscope with a Transmission Detector (STEM) analyses confirmed SA-AuNPs binding. FTIR results showed a well-established bond, through matches of peaks of SA-AuNPs. Bindings between the compounds were more evident in 50-50 concentration of SA-AuNP. In the 30-70 SA-AuNP the STEM images show some superposition of the nanoparticles and not so evident binding, as in the 20-80 concentration. Still, between these last two concentrations, the 30-70 is the one that shows the best results since it is visible some circular points larger than the others. To achieve the goal, the concentrations 30-70 and 50-50 of SA-AuNP were impregnated (Textile Foulard) in two substrates of different compositions, a cellulosic and a synthetic one. However, in this technique there are many parameters, such as drying time and temperature, which were varied to understand which the best procedure was to obtain the biosensor.