Light-Based Device that Uses Few Drops of Saliva to Detect Covid


Researchers at ICFO and IrsiCaixa developed an inexpensive, portable, and non-invasive, light-based device. It detects COVID19 in patients in less than 30 minutes. The results have shown that the device detects very low concentrations of SARS-CoV-2. Moreover, it has a sensitivity of 91.2% and a specificity of 90%. It is the same as PCR testing but much faster than the antigen test.

The Need for Immediate Testing

Marisa Rodriguez and Jorge Carrillo, researchers at IrsiCaixa said,

“At the beginning of the pandemic, we knew it was really important to detect all those infected individuals in order to control the virus spread. That’s why IrsiCaixa researchers, with Bonaventura Clotet at the helm of the initiative, got together and saw the need to find an alternative to PCR and antigen tests that would combine the advantages of each of them, and that would also detect SARS-CoV-2 infection from saliva samples as it is much simpler and less invasive to obtain for most patients..”

They had the idea in mind and contacted ICFO to seek technology for light-based imaging and diagnostic devices.

Alfredo Ongaro, ICFO researcher vividly remembers when they were contacted and said,

“Researchers from IrsiCaixa contacted us to see if we could come up with a solution to the problem of testing and provide a new device that could detect SARS-COV-2 from saliva, avoiding painful nasal swab sampling, and achieve accurate results in short time scales, possibly as fast as an antigen test”

Light-Based Detection (A Flow Virometer)

The team made a flow virometer that uses light for the detection of the virus concentration in the liquid flowing through a very small tube (microfluidic change).

Rubiya Hussain, ICFO researcher said,

“The device uses a couple of drops of saliva and fluorescent light markers. When saliva is collected from the saliva of a patient’s mouth, we introduce it in a solution that contains fluorescent antibodies. If the saliva contains any presence of viral particles, the fluorescent antibodies will attach to the virus.”


The low cost and simple use can make it an excellent solution for COVID-19 diagnosis. In addition to spreading control in lower socioeconomic countries that have limited access to vaccines and healthcare.


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