Optimizing the performance of silica nanoparticles functionalized with a near-infrared fluorescent dye for bioimaging applications.

Modified fluorescent nanoparticles continue to emerge as promising candidates for drug delivery, bioimaging, and labeling tools for various biomedical applications. The ability of nanomaterials to fluorescently label cells allow for the enhanced detection and understanding of diseases. Silica nanoparticles have a variety of unique properties that can be harnessed for many different applications, causing their increased popularity. In combination with an organic dye, fluorescent nanoparticles demonstrate a vast range of advantageous properties including long photostability, surface modification, and signal amplification, thus allowing ease of manipulation to best suit bioimaging purposes. In this study, the Stöber method with tetraethyl orthosilicate (TEOS) and a fluorescent dye sulfo-Cy5-amine was used to synthesize fluorescent silica nanoparticles. The fluorescence spectra, zeta potential, quantum yield, cytotoxicity, and photostability were evaluated. The increased intracellular uptake and photostability of the dye-silica nanoparticles show their potential for bioimaging.