Mitochondria-Targeting Nanoplatform with Fluorescent Carbon Dots for Long Time Imaging and Magnetic Field-Enhanced Cellular Uptake

In this study, a biocompatible nanoplatform has been constructed on the basis of magnetic mesoporous silica nanoparticles (Fe3O4@mSiO2) via surface modification of triphenylphospine (TPP) and then conjugation with fluorescent carbon dots (CDs). The as-prepared Fe3O4@mSiO2-TPP/CDs nanoplatform shows a very low cytotoxicity and apoptosis rate in various cell lines such as A549, CHO, HeLa, SH-SY5Y, HFF, and HMEC-1. More importantly, this nanoplatform integrates long time cell imaging, mitochondria-targeting, and magnetic field-enhanced cellular uptake functionalities into an all-in-one system. Time-dependent mitochondrial colocalization in all of the cell lines has been proved by using confocal laser scanning microscopy and flow cytometry, while the multicolored fluorescence of the Fe3O4@mSiO2-TPP/CDs could remain bright and stable after coincubation for 24 h. In addition, the cellular uptake efficiency could be enhanced in a short time as a static magnetic field of 0.30 T was applied to the coincubation system of A549 and HFF cell lines. This bionanoplatform may have potential applications in targeted drug delivery for mitochondria diseases as well as early cancer diagnosis and treatment.