Microfluidic Biosensor Development for Multiplexed Rapid Detection of Malaria, Typhoid Fever, and HIV at Point-of-Care Settings in North East Nigeria

Syndromic febrile illness in North East Nigeria requires differential diagnosis of malaria, typhoid fever, and HIV, yet sequential single-test approaches are time-consuming, expensive, and often unavailable in peripheral settings. This research develops and validates a microfluidic biosensor platform for simultaneous multiplexed detection of these three priority pathogens at point-of-care settings. The research follows a four-phase innovation design. Phase one involves microfluidic channel fabrication on PDMS using soft lithography with optimisation for whole-blood processing without pre-analytical centrifugation. Phase two develops electrochemical immunosensor modules using gold nanoparticle-enhanced antibody-antigen capture for HRP2 antigen, Salmonella Typhi Vi antigen, and HIV p24 antigen, with independent signal channels per analyte. Phase three optimises multiplexing, cross-reactivity mitigation, and analytical sensitivity benchmarking against reference methods on clinical samples from Yola and Maiduguri. Phase four conducts prospective clinical validation in 300 febrile patients at primary health centres, assessing diagnostic accuracy, operational feasibility, and user acceptability with minimally trained health workers. The device will be battery-operable and provide a digital readout via smartphone Bluetooth connectivity. Original contributions include the first Nigerian-designed multiplexed microfluidic biosensor for syndromic fever, a novel biosensor architecture for simultaneous three-analyte whole-blood testing, and a feasibility model for technology transfer and local manufacturing. The research contributes to indigenous health technology development capacity in Nigeria. Keywords: microfluidic biosensor, point-of-care, multiplexed diagnostics, malaria typhoid HIV, North East Nigeria