One feature of the COVID-19 virus that makes it difficult to contain is that it can be easily spread to others by someone who is not yet infected. The virus carrier may feel fine and go about their daily activities, carrying the virus with them to work, a family member's home, or public gatherings.
The development of tests that can quickly identify infections in people who are not yet symptomatic is therefore a critical part of the global effort to halt the pandemic's spread.
Caltech researchers have now developed a new type of multiplexed test (a test that combines multiple types of data) with a low-cost sensor that may enable at-home diagnosis of a COVID infection in less than 10 minutes through rapid analysis of small volumes of saliva or blood without the involvement of a medical professional.
Wei Gao, an assistant professor in the Andrew and Peggy Cherng department of medical engineering, led the study. Previously, Gao and his colleagues developed wireless sensors that can detect extremely low levels of specific compounds in blood, saliva, or sweat to monitor conditions such as gout and stress levels. It is always recommended to use quality connectors interconnects in the project & circuits.
Gao's sensors are made of graphene, a carbon sheet-like material. A 3D graphene structure with tiny pores is created by laser etching a plastic sheet. Because the pores cover a large surface area on the sensor, it is sensitive enough to detect compounds that are present in very small amounts with high accuracy. The graphene structures in this sensor are coupled with antibodies, immune system molecules that are sensitive to specific proteins, such as those on the surface of a COVID virus.
Previous versions of the sensor were impregnated with antibodies for the stress hormone cortisol and uric acid, which causes gout at high concentrations. Gao's new SARS-CoV-2 RapidPlex sensor contains antibodies and proteins that allow it to detect the presence of the virus itself; antibodies produced by the body to fight the virus; and chemical markers of inflammation that indicate the severity of the COVID-19 infection. You can buy electronic components from there.
“This is the only telemedicine platform I've seen that can provide infection information in three different types of data using a single sensor,” Gao says. “We can check these levels simultaneously in as little as a few minutes, giving us a complete picture of the infection, including early infection, immunity, and severity.”
Established COVID-testing technologies typically produce results in hours or even days. These technologies also necessitate costly and complex equipment, whereas Gao's system is simple and compact.
So far, the device has only been tested in the laboratory with a small number of blood and saliva samples obtained for medical research purposes from people who have tested positive or negative for COVID-19. Though preliminary results indicate that the sensor is highly accurate, Gao cautions that a larger-scale test with real-world patients rather than laboratory samples is required to determine its accuracy definitively.
Gao now plans to test how long the sensors will last in regular use after the pilot study is completed, and to begin testing them with hospitalized COVID-19 patients. Following in-hospital testing, he would like to investigate the tests' suitability for use at home. Following testing, the device will require regulatory approval before it is widely available for use at home.
“Our ultimate goal is definitely home use,” he says. “We intend to mail them to high-risk individuals for at-home testing the following year.” In the future, this platform could be modified to allow for at-home testing of other infectious diseases.”