Magnetically localized and wash-free fluorescent immuno-assay: From a research platform (MLFIA) to a multiplexed POC system (MagIA)

Abstract

Sexually transmitted infections (STI) remain one of the world's public health priorities: Nearly 400 million people are infected not only in emerging, but also in western countries. HIV, HBV and HCV share common infection pathways; thus these 3 diseases are recommended to be tested at the same time. However, this combined approach is currently mainly available in laboratories, and seldomly at the Point-of-care (POC). Consequently, there is a need for a STI screening POC platform with laboratory-like performance. Such a platform should be autonomous and portable and enable multiplexed screening from capillary blood. The previously developed and introduced MLFIA (Magnetically Localized and wash-free Fluorescent Immuno-Assay) technology has the potential to address these needs, as the MLFIA 18-chamber microfluidic cartridge and the MLFIA Analyzer were previously characterized and evaluated with plasma and serum from patients infected with HIV, Hepatitis B (Hep B) or C (Hep C). Here, we present the efforts to transfer this research platform (MLFIA) to a fully integrated multi-analysis solution (MagIA). First, we present the design changes of the consumable enabling to perform multiple assays in parallel, a fast filling of the cartridge with patient samples, and a homogeneous reagent/sample incubation. Second, we describe the development a piezoelectric actuator integrated into the Analyzer: this mixing module allows for an automated, fully integrated and portable workflow, with homogeneous in-situ mixing capabilities. The obtained MagIA platform was further characterized and validated for immunoassays (LOD, cartridge stability over time), using various biological models including OVA and IgG. We discuss the performances of the MLFIA and MagIA platforms for the detection of HIV / Hep B / Hep C using results from 102 patient plasma samples. Lastly, we assessed the compatibility of the MagIA platform with veinous and capillary blood samples as a final step towards its POC validation.