Development of a Microfluidic-Integrated Magneto-Immunoassay for Early HIV Detection

HIV remains a major global health challenge more than four decades after its discovery, with an estimated 39 million people living with the virus in 2022, including 1.3 million new infections and 630,000 HIV-related deaths (UNAIDS). Current diagnostic approaches include laboratory-based assays, which are highly accurate but labor-intensive and require clinic visits, and rapid antibody (Ab) tests, which offer point-of-care convenience, particularly for individuals using Pre-Exposure Prophylaxis (PrEP). However, rapid Ab tests are limited by delayed seroconversion and cannot reliably detect early-stage or acute infections, nor directly identify viral particles. This creates a critical need for more sensitive methods for early detection of HIV.

In this study, we developed magnetic bead–based electrochemical immunoassays capable of detecting HIV-1 p24 at picogram-per-milliliter (pg/mL) concentrations. Several antibody detection strategies were evaluated to optimize both sensitivity and quantitative performance. By combining efficient target capture with signal amplification, the assays achieved high sensitivity across a broad dynamic range while maintaining operational simplicity. A comparison of antibodies conjugated with horseradish peroxidase (HRP) and poly-HRP confirmed proportional increases in electrochemical signal with rising p24 concentrations in spiked serum samples. The magneto-immunoassays were further validated using inactivated virus samples. Preliminary integration with a microfluidic device highlighted the platform’s potential for early HIV detection and adaptability for monitoring additional clinically relevant biomarkers. Future work will focus on developing a multiplex, capillary-driven immunoassay capable of simultaneously detecting HIV p24 antigen and HIV antibodies.