Point-of-care diagnostic device for dengue fever from a single drop of blood
Dengue fever is caused by the dengue virus, transmitted mainly through the female Aedes aegypti mosquito, found in more than 120 countries worldwide. Dengue virus can cause an acute flu-like illness which may develop into a potentially lethal complication called severe dengue. Prompt access to medical care limits fatality rates of severe dengue to below 1 %.
Detecting multiple dengue fever biomarkers at once
Diagnosis relies on direct detection of viral genome and antigens or indirect serological tests for the capture of host antiviral antibodies. However, both approaches are time consuming and require specialised instrumentation and trained personnel. To address these limitations of existing diagnostic tests, the EU-funded COMBO project has developed an in vitro diagnostic device for fast, easy diagnosis of dengue fever. “Our goal was to provide robust and accurate point-of-care diagnosis applicable to developing countries, but also to determine the severity of the infection,” emphasises Maarten van der Linden, project coordinator and CEO of BluSense Diagnostics. The COMBO platform consists of the BluBox reader and a set of microfluidics cartridges allowing one or multiple immunoassays to be performed from a single drop of blood. For dengue fever, the team has developed a solution which can simultaneously measure and quantify both the dengue virus NS1 antigen (indicative marker for acute dengue fever) and dengue IgG and IgM antibodies. Importantly, the entire process, from sample to result, takes less than 15 minutes. The combination of the three dengue markers allows differentiation between primary and secondary infections, which is instrumental in advising on the right treatment and preventing severe dengue and haemorrhagic dengue fever. In terms of performance, the immunoassay cartridges match the state-of-the-art laboratory-based enzyme-linked immunosorbent assay (ELISA) analysis, which conventionally takes roughly 2 to 4 hours to produce results. Similar performance has been reported for the cartridge that detects the dengue virus NS1 antigen.
A convenient and adaptable platform for infectious disease
Dengue virus is endemic in tropical and subtropical areas, where the healthcare infrastructure and budget can only cope with a fraction of the million patients that get infected every year. The COMBO platform has the potential to improve the current situation by distinguishing severe cases that require immediate hospitalisation from those that can be monitored at home. According to van der Linden, “this wouldn’t have been possible without the introduction of three different assays on a single cartridge.” Researchers have improved the microfluidics and assay performance, making the cartridge very easy to use and produce. Moreover, BluSense has introduced a semi-automated production line that allows the creation of more than 5 000 cartridges per week. Because the COMBO cartridge platform is very flexible, it can host other assays beyond dengue antigen and antibodies. Partners therefore aim to expand the test portfolio to other infectious diseases and transform the platform into a generic infectious disease platform. The product range has grown to include cartridges for the detection of COVID19 antibodies, while the BluBox device has been validated for the detection of Zika virus. This is expected to facilitate introduction of the BluBox reader in several European countries.
Keywords
COMBO, dengue fever, antibodies, cartridge, BlueBox reader, NS1 antigen, point-of-care device
