Glucometer Detects SARS-CoV-2 Antibodies Quickly
Glucose meters, which are readily available, easy to use and can be integrated with remote clinical services. Researchers have been adapting these devices to sense other target molecules, coupling detection with glucose production.
If a detection antibody in the test binds to an antibody in a patient’s blood, then a reaction occurs that produces glucose something the device detects very well.
Invertase is an attractive enzyme for this type of analysis because it converts sucrose into glucose, but it’s difficult to attach the enzyme to detection antibodies with chemical approaches.
So, Netzahualcóyotl Arroyo-Currás, Jamie B. Spangler and colleagues wanted to see whether producing a fusion protein consisting of both invertase and a detection antibody would work in an assay that would allow SARS-CoV-2 antibody levels to be read with a glucose meter.
Role of Novel Fusion Protein
The researchers designed and produced a novel fusion protein containing both invertase and a mouse antibody that binds to human immunoglobulin (IgG) antibodies.
They showed that the fusion protein bound to human IgGs and successfully produced glucose from sucrose. Next, the team made test strips with the SARS-CoV-2 spike protein on them.
When dipped in COVID-19 patient samples, the patients’ SARS-CoV-2 antibodies bound to the spike protein. Adding the invertase/IgG fusion protein, then sucrose, led to the production of glucose, which could be detected by a glucose meter.
They validated the test by performing the analysis with glucose meters on a variety of patient samples, and found that the new assay worked as well as four different ELISAs. The researchers say that the method can also be adapted to test for SARS-CoV-2 variants and other infectious diseases.