Emerging Trends in Fluorescent and Quenching Nanomaterials for Viral detection: Innovations in Biological and Chemical sensing

• Fluorescent and quenching nanomaterial-based structures are integrated into optical biosensors for the purpose of extraordinary sensitivity and specificity, thus enabling direct detection during the diagnosis of viral pathogens. • The quenching mechanism-based nanocomposites fluorescence have excellent multimodal detection properties, with a high signal-to-noise ratio and stability, and also have great flexibility for use in point-of-care settings. • The mechanisms for increased sensitivity could also be in combination with FRET and localized surface plasmon resonance to enhance detection for ultra-low concentrations of virus. • Optical biosensors are quite promising, although still ahead of considerable challenges related to cost-effective scaling up, reproducibility, and regulatory approvals, which call for intensive multidisciplinary efforts to be conquered. • Future biosensors will be used with artificial intelligence meaning its intelligent diagnostics ability, along with multiplexing and nanomaterials biocompatibility along with sustainability for universal applications. Optical biosensors doped with nanomaterials are the most technologically advanced in viral diagnostics, showing higher sensitivity, specificity, and speed of detection. This review describes the role of fluorescent and quenching nanomaterials in the development of optical biosensing techniques. These sensors enable real-time, non-invasive viral detection with minimal preparation of samples by exploiting unique optical properties of nanomaterials, such as increased fluorescence, efficient energy transfer, and significant signal amplification. It is worth noting that the material's application in point-of-care settings effectively bridges laboratory accuracy with the practical applicability of real-world applications. Moreover, these aspects were put into review, along with the latest advancements in the emerging dual-functional nanocomposites able to integrate the fluorescence and quenching mechanisms for multimodal detection, with emphasis on what has been recently achieved and how these efforts have been developed to tackle stability, reproducibility, and scalability concerns. This will enable optical biosensing through advances in nanotechnology and pave the way for designing next-generation diagnostic platforms capable of addressing current and emerging viral threats.