What Does COVID-19 (and some other diseases) Smell Like?

To detect SARS-Cov-2 is necessary to carry out tests in specific places, which are impractical and time consuming. The method proposed for development involves: detailed identification of the Volatiloma (VOC) carrying by the virus by using smell sensors.

Dr. José Luis Gordillo

National Laboratory for Robotics - CONACyT-ITESM
Leader of the Research Group on Robotics, School of Engineering and Sciences - EIC
Tecnologico de Monterrey
5o piso Torre Sur, CETEC
Av. Eugenio Garza Sada 2501       Email: JLGordillo@Tec.mx
64849 Monterrey, N.L., MEXICO     Home Page: http://tec.mx/es/Robotica

As an example of the pandemic impact, until April 2021, 135.2 million confirmed cases of COVID-19 had been reported worldwide (2,926,000 deceased)

However, so far, there is no instrument that allows us to get an early identification of the disease, especially in asymptomatic patients; this is the fundamental reason to have non-invasive instruments for the identification of volatile compounds present in the exhaled air of patients with suspected SARS-CoV-2.

Based on the identification of the specific VOC, this method will be useful to face future pandemics to design the sensors and focus their responses.

This device is intended to be an auxiliary tool in the early diagnosis of COVID-patients to decrease complications and transmission risk. Most positive cases are detected only on the 7th or 8th day when symptoms appear or complications develop. Hence, the spread of asymptomatic patients in communities, schools, workplaces or has been indiscriminate.

Therefore, although there are five basic senses (hearing-touch-sight-taste-smell), which we use daily to orient ourselves to perceive danger, people tend to rely more on vision and hearing to obtain information about their environment, neglecting smell. Unaware that we retain the ability to detect and discriminate many odorous molecules and complex mixtures of molecules.

In some reports, in the case of COVID-19, patients can detect or perceive a different odor before the onset of the most characteristic symptoms (headache, cough, nasal discharge), hence the present study's importance. So far, no instrument allows early identification of the disease, especially in asymptomatic patients; this is the fundamental reason for the availability of non-invasive instruments for the identification of volatile compounds present in the exhaled air of patients with suspected SARS-CoV-2.

Early SARS-COV-2 virus response and detection according to its "molecular footprint" through a specific VOC sensor will enable a broad, low-cost detection of COVID-19 patients in the asymptomatic phase. This VOC-specific analyzer is a portable sensor that allows access to this test to many people. Besides, VOC-specific analysis could be carried out by people with basic training and relatively short time. This approach could allow prompt isolation, persistent monitoring and proper treatment, and being a useful tool to help stop virus spread as much as possible.

Simultaneously, using this method and technology will provide tools for characterizing new viruses and fast-developing efficient smell sensors for the new disease.

Mexico currently has the third-highest number of deaths from the COVID-19 pandemic worldwide. One of the reasons for this evolution in the country has been the shortage of PCR testing. Despite being at high risk of infection in asymptomatic subjects, the absence of PCR testing and the lack of knowledge of their carrier status increase infection to spread.

Among the constraints to the lack of testing are the cost, availability and accessibility of testing in specialized laboratories with adequate quality standards. Other countries with the same emerging conditions as Mexico have had the same problems.

A portable, low-cost and easy-to-use COVID-specific VOC-sensor will overcome this problem in countries with economically compromised situations, such as most Latin American and African countries. These type of sensors will facilitate the early identification of sick, asymptomatic carriers or patients with complications. The possibility of repeated testing at a low cost will allow adequate follow-up of cases. This sensor model could be extended to other pathologies with similar clinical and epidemiological conditions and presentations in the long term.

One year:

During the first year, BEC samples from COVID-19 patients in the first seven days of evolution and subjects without the disease will be collected for processing on the GS-MS Chromatograph to identify differential compounds between the two conditions. 

To develop a copper, gold, and silver doped sensor that responds to VOCs present in BEC samples from COVID patients.

Additionally, the implementation of an electronic nose equipped with an array of sensors formed out of the previous doped sensors to differentiate the VOCs present in respiratory diseases.

Three years:

Several identification tests will be carried out in patients with and without COVID-19 in a diagnostic test design during this time. Up next the development of a portable sensor prototype with a process of integration and miniaturization of the elements that integrate it.

For the sensor manufacture approach, a new method will be applied in order to design smaller sensors using spray pyrolysis on silicon wafer as substrates, and with this creating a more sophisticated technology.

One year:

To follow up on the impact of our research and to monitor our progress. The first year is necessary to: manufactured a specific number of each doped sensor having an inventory capable of producing several electronic noses, which will allow us to characterize the signal coming from the VOCs components in BEC from covid-positive patients. The signal analysis in this phase will be critical because a deep pattern signal analysis has to be effectuated to differentiate the  VOCs samples.

Three years:

At the end of the third year, the electronic nose's creation using micro-assembly parts will facilitate the detection of respiratory diseases in a more controlled environment due to its handy size. Size reduction will allow the medical group to take measurements in a more controlled environment. The evaluation will be performed through a state-of-the-art comparison that contemplates several characteristics: sensitivity, response time, and stability.

The development of a COVID-VOC-Sensor depends on identifying specific volatile substances present in the condensed exhaled breath of patients with early SARS-COV2 involvement. It is important to determine the chromatograph conditions such as the type of column, the carrier gas, the injection temperature and the ionization energy.

The main barrier to carry out this step is the lack of own infrastructure, the GS-MS chromatograph. This equipment is accessible with other institutions' support, with restrictions on availability due to other uses, making contamination of the samples possible.

The second step is the design of sensors based on the recognition of specific VOCs. Nowadays, the technology used for the manufacture of sensors is out of date. There is an inherent necessity to update the machinery to create even more specialized sensors, and with this, get the migration to future miniaturization applications overcoming this barrier.

Tecnológico de Monterrey, Monterrey, México.

Universidad Autónoma de San Luis Potosí – UASLP, México

Tecnológico Nacional de México, Campus Nuevo León, México

Our most important barriers to achieving the proposed goals are the lack of adequate and modern infrastructure to adequately carry out the steps described above, financial support for training human resources in research and obtaining the necessary consumables to do so. The search for international agencies that could support this type of project allowed the Trinity Challenge to be identified as a probability.

Our initiative meets the vision of the Trinity Challenge regarding safeguarding human lives by using Scientific methodology to respond to health emergencies. Also, follow the foundation's three principles: inclusivity given that if the sensor is obtained, it can be made available at low cost for worldwide distribution; collaboration with the joint work of groups of researchers from three Mexican universities; and innovation has given the focus on COVID-VOC specific sensors that allow massive, accessible and early diagnostic testing.

Unfortunately, we recently know of this initiative, and we have not a clear and detailed idea of all the partner organizations. In that case, we are initially interested in contributing and collaborating with academic organizations like ours.