Magnetic SERS-based lateral flow immunoassay for ultrasensitive on-site detection of Chikungunya virus in mosquito vectors.

The Chikungunya virus (CHIKV) is a significant re-emerging mosquito-borne pathogen primarily transmitted by Aedes aegypti mosquitoes. Its clinical symptoms (e.g., fever and arthralgia) are similar to those of other arboviral infections, frequently leading to misdiagnosis or underdiagnosis in resource-limited areas. Therefore, there is an urgent need for rapid, on-site screening techniques suitable for mosquito vectors to enable early monitoring and warning of arbovirus transmission. To address the inherent challenges of low viral load and complex matrices in mosquito samples, this study developed a lateral flow immunoassay (LFIA) biosensor based on Fe₃O₄@Au magnetic SERS tags. This platform integrates magnetic enrichment with ultrasensitive SERS detection. Driven by an external magnetic field, it enables efficient concentration and purification of trace CHIKV. The assay achieved detection limits (LOD) of 15 pg mL⁻¹ for purified recombinant CHIKV E1 protein and 887 copies mL⁻¹ for inactivated whole virus. Importantly, the platform has been successfully detected CHIKV in field-collected, positive mosquito samples, with results consistent with those from reverse transcription quantitative PCR (RT-qPCR). Collectively, these findings demonstrate the strong potential of this biosensor as a practical tool for the on-site screening and early monitoring of mosquito-borne viruses, providing substantial support for its future application in public health and field surveillance.