ESS - CISA – Centro de Investigação em Saúde e Ambiente
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- Development of a sustainable biosensor to detect respiratory infectious diseasesPublication . Nascimento, Ana Margarida; Abreu, Cristina; Silva, M.; Leite, B.; Rouly, S.; Abreu, M. J.; Ferraz, Ricardo; Costa, M.; Prudêncio, Cristina; Parente, E.; Vieira, Mónica; Ferraz, Ricardo; Vieira, Mónica; Prudêncio, CristinaThe 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.
- Development of biosensors for functional textile applicationsPublication . Nascimento, Ana; Abreu, Cristina; Silva, Mariana; Leite, Bárbara; Rouly, Simon; Ferraz, Ricardo; Costa, Miguel; Prudêncio, Cristina; Parente, Elsa; Vieira, MónicaSARS-CoV-2, the cause of the disease COVID-19, has a high level of contagiousness, and has been verified as a major epidemiological threat. In order to reduce the spread of the virus, the entire population was advised to use personal protective equipment, among which are the face masks. The eficacy of masks depend on the time of use, amount of moisture and contact with infectious agents. The objective of this study is the development of a colorimetric biosensor, based on biological reactions that detect a given analyte through color change. This biosensor will be incorporated in a textile surface, with the capacity of direct indication of the protection effectiveness of the face masks, giving the user information about the filtration level of the equipment, with a humidity sensor; and of the contamination space, with a sensor to detect the presence of the virus. Thus, a biosensor for SARS-CoV-2 is intended to indicate the contact with the virus. It was developed based on gold nanoparticles functionalized with sialic acid, to be coupled with a humidity biosensor and previously presented to scientific community. The humidity biosensor is intended to contribute to reduce the risk spread and contagion of the disease, by monitoring the effectiveness of the protection of the masks, since humidity causes the degradation of the filtering quality of the masks. For the development of the humidity biosensor, two approaches were adapted: clay and silica mesoporous, which will be impregnated, together with the SARS-CoV-2 biosensor, on a textile surface, and then incorporated into the textile mask. The developed biosensor appears to be more reliable through silica-based technology with methylene blue dye, is aligned with the Portuguese standard for textile face masks that indicate up to 4 hours of use and [85±5]% of maximum relative humidity, as maximum levels expected for the inutilization of the masks. After reaching this humidity the biosensor changes color, indicating to us the need for mask replacement.