Nano-fluorophores as enhanced diagnostic tools to improve cellular imaging

Biological events can be mapped in real-time using fluorescent images at high spatial resolution through the use of a powerful tool called fluorescence, and it is necessary to have ultra-bright fluorescent probes. The detrimental effects associated with the existing fluorescence imaging probes and contrast agents are the primary reason behind the greater involvement of nanotechnology. Developing advanced particles at the molecular and supramolecular levels is the only way to address the constraints underlying the current scenario. Nanosized structures dominate in multiple fields, especially in nanotheranostics, due to their higher quantum yield, negligible photobleaching, excellent biocompatibility, tunable optical properties, and improved circulation half-lives. Nanofluorophores, which are nanoparticles encapsulated or doped with fluorescent dyes, play a crucial role in fluorescence-based imaging modality by providing noninvasive real-time monitoring of the inner machinery of the anatomical and cellular structures. In addition to fluorescent inorganic and organic nanoparticles, there are labeled hydrophilic and hydrophobic nanostructures, semiconducting dots, carbon dots, as well as upconversion nanomaterials, etc., which are widely used in fluorescent imaging. A comprehensive literature survey has been provided in this review since intense studies are needed to clear the preclinic stage, thus opening up opportunities for future biomedical applications.