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Browsing by Author "Cruz, Maria Teresa"

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  • Development of colorimetric cellulose-based test-strip for the rapid detection of antibodies against SARS-CoV2 virus
    Publication . Correia, Bárbara P.; Sousa, Mariana P.; Sousa, Cristina E. A.; Mateus, Daniela; Sebastião, Ana Isabel; Cruz, Maria Teresa; Matos, Ana Miguel; Santos Pereira, Ana Cláudia; Moreira, Felismina
    Given the pandemic situation, there is an urgent need for an accurate test to monitor antibodies anti-SARS-CoV-2, providing crucial epidemiological and clinical information to monitor the evolution of coronavirus disease in 2019 (COVID-19) and to stratify the immunized and asymptomatic population. Therefore, this paper describes a new cellulosebased test strip for rapid and cost-efective quantitative detection of antibodies to SARS-CoV2 virus by colorimetric transduction. For this purpose, Whatman paper was chemically modifed with sodium metaperiodate to introduce aldehyde groups on its surface. Subsequently, the spike protein of the virus is covalently bound by forming an imine group. The chemical control of cellulose paper modifcation was evaluated by Fourier transform infrared spectroscopy, thermogravimetry and contact angle analysis. Colorimetric detection of the antibodies was performed by a conventional staining method using Ponceau S solution as the dye. Color analysis was performed after image acquisition with a smartphone using Image J software. The color intensity varied linearly with the logarithm of the anti-S concentration (from 10 ng/mL to 1 μg/mL) in 500-fold diluted serum samples when plotted against the green coordinate extracted from digital images. The test strip was selective in the presence of nucleocapsid antibodies, urea, glucose, and bovine serum albumin with less than 15% interference, and detection of antibodies in human serum was successfully performed. Overall, this is a simple and afordable design that can be readily used for mass Abstract Given the pandemic situation, there is an population screening and does not require sophisticated equipment or qualifed personnel
    2022Journal article Restricted access Show more