Researchers at the Federal University of São Carlos (UFSCar) have developed a new strategy to detect the coronavirus cause of Covid-19. It is the combination of an enzyme found in fireflies with a protein able to bind to the new pathogen.
According to reporter José Tadeu Arantes, from Agência FAPESP, belonging to the Foundation for Research Support of the State of S. Paulo, the enzyme used in the research belongs to the class of luciferases, whose role is to catalyze reactions that transform chemical energy into light energy – a phenomenon which is generically called bioluminescence.
Among all the known luciferases, the one produced by the firefly Amydetes vivianii is one that generates the brightest and most stable bioluminescence.
Found on the campus of Sorocaba from UFSCar, the insect was named after Professor Vadim Viviani, who discovered the species and cloned the DNA that encodes the firefly's luciferase into bacteria. The researcher also investigated the molecular structure and functions of the enzyme.
“We took our brightest luciferase and genetically engineered it into a protein capable of binding to antibodies. If antibodies against SARS-CoV-2 are present in the sample, binding will occur and this can be detected by means of light emission”, explained Viviani.
Likewise, the presence of specific SARS-CoV-2 proteins, indicating infection, can be detected by the bioluminescent molecule in the presence of specific antibodies.
The study was completed in less than a year, with exclusive resources from the Thematic Project “Bioluminescence of arthropods: biological diversity in Brazilian biomes; biochemical origin; structural/functional evolution of luciferases; molecular differentiation of lanterns; biotechnological, environmental and educational applications”, supported by FAPESP.
Viviani says that she has already filed a patent application for the new bioluminescent system with the National Institute of Industrial Property (INPI) and says that the study is so recent that the article describing it is still in the drafting phase.
“We have successfully tested the method for several antibodies, which can be detected by techniques such as immunoblots and Western Blot”, says Viviani.
“In immunoblots, antigen samples are immobilized on a surface. Then treated with materials such as the patient's blood serum. If the material contains the antibody, it binds to the antigen, forming the antigen-antibody complex, which is revealed by a secondary antibody – usually labeled with a protein that generates a fluorescent or chemiluminescent signal. In our study, the labeled secondary antibody is a protein with high affinity for antibodies, linked to luciferase, which generates bioluminescence”, informs Viviani.
Western Blot is a method that allows you to separate proteins in a sample of biological tissues or extracts. The method separates the proteins through electrophoresis, a technique that promotes the migration of ions in an electric field, making it possible to separate them according to their size and charge.
The work was developed at UFSCar's Laboratory of Biochemistry and Bioluminescent Technologies and had the collaboration of Paulo Lee Ho, from Butantan Institute.
The goal is to apply Covid-19's technology in rapid, non-invasive testing
According to Viviani, the next step is to know if the amount of antibodies present in saliva or nasal swab (swab) is enough to trigger bioluminescence, so that the new biosensor can be used in rapid and non-invasive testing for Covid-19 .
“To take this second phase of the research forward, we are already in talks with researcher Heidge Fukumasu, from the University of São Paulo (USP). Another perspective will be the use of nanotechnology to develop immunoassays in collaboration with the research group of Professor Iseli Nantes, from the Federal University of ABC [UFABC],” says Viviani.
“This study is an example of how a small species of firefly can provide so many benefits to society. An example of how the biodiversity of our forests and science, both so severely threatened, can, together, bring innovative solutions and add economic and social value to a developing country like Brazil”, concludes the researcher.