Session topic


Title: A high-throughput microfluidic nano-immunoassay for detecting anti-SARS-CoV-2 antibodies in serum or ultra-low volume dried blood samples
ID: O 60
Type: Abstract talk
Talk time: 12 + 3 min
Session: Workshop 10
Clinical virology I

Speaker: Benjamin Meyer (Geneva/CH)

Abstract - Text

Abstract text (incl. references and figure legends)

SARS-CoV-2 seroprevalence studies are currently conducted world-wide to determine the spread of the virus and monitor the level of population immunity already reached. With the recent roll-out of multiple vaccines, it will become increasingly important to differentiate the humoral immune response elicited by vaccination compared to natural infection to determine the rate of asymptomatic infections in vaccinated individuals or a potential vaccine break-through in epidemiological studies. Multiple serological assay have been developed that can reliably measure antibodies in serum or capillary blood samples. However, all methods require either serum drawn by venipuncture or in case of lateral flow antibody assays the sample is lost and cannot be analyzed further. This is an important problem especially in low- and middle-income countries where it is difficult to collect serum samples and send it to central laboratories and maintain an intact cold chain. Therefore, novel technologies are needed that facilitate the large-scale detection and quantification of SARS-CoV-2 specific antibodies in human blood samples.

We developed a microfluidic nano-immunoassay for the detection of anti-SARS-CoV-2 IgG antibodies in up to 512 samples per device. The method achieved a specificity of 100% and a sensitivity of 98% based on the analysis of 289 human serum samples, including 134 pre-pandemic sera and 155 samples from COVID-19 patients (102 ≤20 days post onset and 53 >20 days post onset). To eliminate the need for venipuncture, we developed low-cost, ultra-low volume whole blood sampling methods that require only a simple finger prick that can be done conveniently at home. These dried capillary blood samples can be shipped under standard conditions at ambient temperatures to a central laboratory. This methods are therefore suitable for low and middle-income countries where it is difficult to maintain a cold chain during transport or for patients from whom it is difficult to collect venous blood, i.e. children. We found that detection of anti-SARS-CoV-2 IgG antibodies is comparable or even more sensitive than a commercially available ELISA.

In conclusion the nano-immunoassay platform achieves high-throughput, high sensitivity and specificity, negligible reagent consumption, and a decentralized and simple approach to blood sample collection. We expect this technology to be immediately applicable to current and future SARS-CoV-2 related serological studies.