Developing an Optical Interferometric Detection Method based biosensor for detecting specific SARS-CoV-2 immunoglobulins in Serum and Saliva, and their corresponding ELISA correlation.

The standard rapid approach for the diagnosis of coronavirus disease 2019 (COVID-19) is the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA. The detection of specific anti-SARS-CoV-2 immunoglobulins is crucial for screening people who have been exposed to the virus, whether or not they presented symptoms. Recent publications report different methods for the detection of specific IgGs, IgMs, and IgAs against SARS-CoV-2; these methods mainly detect immunoglobulins in the serum using conventional techniques such as rapid lateral flow tests or enzyme-linked immunosorbent assay (ELISA). In this article, we report the production of recombinant SARS-CoV-2 spike protein and the development of a rapid, reliable, cost-effective test, capable of detecting immunoglobulins in serum and saliva samples. This method is based on interferometric optical detection. The results obtained using this method and those obtained using ELISA were compared. Owing to its low cost and simplicity, this test can be used periodically for the early detection, surveillance, detection of immunity, and control of the spread of COVID-19.

A new optical interferometric-based in vitro detection system for the specific IgE detection in serum of the main peach allergen.

Food allergens cause worldwide chronic diseases with a great impact on public health. Immunoglobulins E (IgEs) trigger allergic reactions by specifically binding the allergens to which the allergic patients are sensitized. In this scientific work we report for the first time a new optical interferometric in vitro system for the detection of specific IgEs (sIgEs) to the principal peach allergen (Pru p 3) in real serum samples. Interferometric Optical Detection Method (IODM) was employed for reading out the signal of Fabry-Perot based interferometers acting as biotransducers. Pru p 3 was immobilized as bioreceptor onto the sensing surface for detecting the target biomolecules, sIgEs to Pru p 3. Moreover, the demanding low concentration of IgE, compared to other analytes in real serum samples, made it necessary to use nanoparticles (NPs) for two reasons: to collect only the IgEs from the serum sample and to enhance the optical interferometric read-out signal. The methodology was validated in advance by scanning electron microscopy (SEM). Consequently, we report in this article a novel high-performance in vitro detection method to recognize sIgE to molecular allergens by means of silicon dioxide (SiO2) NPs. Finally, this scientific work provides the basis for the in vitro component resolved diagnosis (CRD) of sIgEs to molecular allergens.