Field Detection of Multiple Infectious Diseases with Naked Eye Using Plasmonic-Enhanced Fluorescent Nanoparticles.

Accurately diagnosing infectious diseases in a resource-limited setting is a major challenge. Plasmonic materials, via localized surface plasmon resonance (LSPR), have greatly enhanced fluorescence signal and detection sensitivity. However, traditional plasmonic-enhanced fluorescence methods largely rely on near-infrared or visible-light fluorophores with small Stokes shift, limiting naked-eye visibility without filters. In this study, we developed a novel plasmonic silver film (pSilverF) to enhance visible-light fluorescence with large Stokes shift, allowing for improved biomarker detection sensitivity under naked-eye observation. Integrated with bright fluorescent nanoparticles, we designed a multiplexed assay for detecting Hepatitis C Virus (HCV), Hepatitis B Virus (HBV), and Human Immunodeficiency Virus (HIV) antibodies, achieving detection sensitivities down to 0.0032, 0.023, and 0.168 NCU/mL, respectively. In a cohort of 68 clinical samples, our method achieved 100% sensitivity and specificity for HIV and HCV detection and 96% sensitivity and 100% specificity for HBV detection. Notably, the results can be visualized by the naked eye and directly captured by a standard mobile phone camera without any modification for signal analysis using RGB image splitting. This platform demonstrated potential for field detection of multiple infectious diseases with simple settings, providing a useful tool for disease control in communities and areas with limited medical resources.