Biotin-specific molecularly imprinted polymers as a biomimetic test line in lateral flow assays

Lateral flow assays are widely used for rapid diagnostics at the point of care. However, their dependence on biological receptors limits their stability, scalability, and cost-effectiveness. This work demonstrates the use of biotin-specific molecularly imprinted polymers (biotin-MIPs) as synthetic recognition elements in nucleic acid lateral flow (NALF) assays. The biotin-MIPs were synthesized, structurally characterized, and integrated into the nitrocellulose membrane as a test line. Their selective binding affinity was first validated using biotinylated horseradish peroxidase as a model analyte. The platform was then evaluated for the detection of double-tagged PCR amplicons from Escherichia coli labeled with biotin and digoxigenin, achieving a visual detection limit of 2 ng mL^-1 and a limit of detection of 1.8 ng mL^-1, with no detectable signal in negative controls. Clinical feasibility was further assessed retrospectively using swab specimens collected during routine third-trimester screening (35-37 weeks of gestation) for Group B Streptococcus, a major cause of neonatal sepsis. In this proof-of-concept study, the MIP-based NALF assay showed complete qualitative agreement with the qPCR reference classification and the gold standard microbiological culture, demonstrating the compatibility of this approach with battery-operated portable PCR amplification. Unlike biological receptors, MIPs offer robustness, long-term stability at room temperature, and animal-free scalable production. These features position the MIP-based NALF platform as a cost-effective alternative to antibody-based tests and a promising foundation for next-generation lateral flow diagnostics for the detection of communicable diseases at the point of care.