Rapid Bacterial/Viral Infections Typing Strategy Using a Portable Dual-Channel Electrochemical Biosensor Based on One-Step Assembly of Immunomagnetic Beads

Amidst multiple epidemics, a rapid, sensitive, economical, and portable infection diagnosis strategy is crucial for primary medical care, particularly through the analysis of pathogen sources to determine appropriate antibiotic use. C-reactive protein (CRP) and serum amyloid A (SAA) are host-related biomarkers, and their combined detection can effectively distinguish between bacterial and viral infections, which holds great significance for the diagnosis of unknown pathogens. In this work, a portable dual-channel electrochemical biosensor based on a one-step assembly of immunomagnetic beads was proposed for the on-site combined detection of plasma CRP and SAA, which streamlined the operation and shortened the minimum detection time to less than 3 min. The biosensor exhibited excellent linearity in the detection of 3.125-1250 ng/mL CRP and 31.25-1250 ng/mL SAA, with detection limits of 0.91 and 12 ng/mL, respectively, falling within the clinically relevant reference range. Through simulated sample tests, the biosensor effectively distinguished between bacterial infection, viral infection, and healthy plasma samples. The actual sample tests demonstrated a high correlation and comparable medical value to enzyme-linked immunosorbent assay. Overall, this proposed strategy showed potential to aid in infection diagnosis and enable rapid combined detection of multiple biomarkers.