The coronavirus disease 2019 (COVID-19) has turned into a global pandemic that has caused more than 4 million deaths worldwide as well as massive perturbations at all levels of life, from public administrations and markets to our daily social interactions. Like other emerging virus outbreaks, such as Chikungunya, Zika, or Middle East respiratory syndrome coronavirus (MERS-CoV) viruses, COVID-19 requires a complex strategy to stop its propagation and eventually defeat it. International health authorities recommend prevention and containment measures. This includes social distancing, isolation of contagious cases, and the stringent implementation of hygiene. However, they require strict execution to be effective. In addition, longer-term solutions like vaccine development require significant investment and research to understand the molecular mechanism by which the virus attacks the body and its cells.
The primary means of diagnosis for COVID-19 and other respiratory viruses are:
-Oropharyngeal and nasopharyngeal swab procedures that use biological methods like antibody tests.
-Real-time reverse transcription-polymerase chain reaction (RT-PCR).
-Antigen tests.
However, the successful engineering of these tests involves understanding the components of the virus that require sample pretreatment or labeling, like extraction of the viral DNA or RNA to match a complementary strand. In this context, developing a precise, rapid, intelligent, and cost-efficient test to determine whether a person has been infected with COVID-19 or other viruses is essential to prevent future rebounds of infections and help control the pandemic. Among label-free biosensors, piezoelectric mechanical sensors have unique advantages, i.e. i) the direct measurement of the crystal deformation by electrical methods and ii) the absence of interferences with biomolecules, compared to optical systems. In this regard, α-quartz is the best piezoelectric sensing material with a vast quality factor (Q > 106), exceptional temperature stability, and deficient phase noise. However, to date, α-quartz applied to microelectronics is exclusively synthesized by hydrothermal methods, which produce giant crystals, making it impossible to decrease their size below a thickness of 10 µm. For most applications, these crystals need to be bonded on Si substrates.
The QOVID project aims to make a proof of concept based on the ERC SENSiSOFT α-quartz devices to develop a biosensor that biologists and biomedical faculty can use to detect viruses-mediated biological processes. In short, QOVID wants to scale up the production of α-quartz resonating nano-structured devices with thicknesses between 200 nm and 1 µm, 10 to 50 times thinner than those obtained by top-down technologies on bulk crystals. As a result, we expect to fabricate a new generation of on-chip quartz piezo MEMS capable of measuring tiny masses through a variation in the resonant frequency, piezo-generated charges, or impedance without damping phenomena. Notably, the QOVID project's ambition is to generate new tools and methodologies that can be applied to other relevant emerging pathogens and prepare us to confront future pandemics.
