Fluorescent Silicon Nanoparticles-based Gene Carriers And Their Use For Biological Imaging In Live Cells

With significant advancement of nanotechnology, several types of nanomaterials have been intensively exploited as novel gene carriers with unique advantages. Among them, fluorescent carriers are highly attractive because they can provide possibilities for fluorescence imaging of the gene delivery process. The real-time and long-term bioimaging can help us understand the intracellular behaviors of gene carriers comprehensively, which is also of essential importance for rationally designing high-performance gene vectors. Zero-dimensional fluorescent silicon nanoparticles (SiNPs) have received extensive attentions in recent years. Of particular note, superior optical merits and low-/or non-toxicity of SiNPs make them as potentially idea fluorescent probes for bioimaging applications.In my study, we present the first demonstration of fluorescent SiNPs-based gene carrier and explore its capacity for gene delivery and fluorescence bioimaging. In the DNA binding and protection test, the resultant SiNPs vectors not only exhibit relatively high DNA loading capacity, but also protect the DNA against degradation by nucleases efficiently. The novel gene carriers also have adaptable gene transfection efficiency (GTE,-35%) on Human cervical carcinoma cells (HeLa cells), which is larger than those of polyetherimide (PEI, a kind of commercial non-viral carriers). Moreover, the as-prepared nanocarriers are biocompatible, yielding feeble cytotoxicity during long-time cellular incubation (e.g., HeLa cells maintain ?90% cell viability when treated by the resultant carriers for 24 and 48 h).Besides, taking advantages of the unique optical properties of SiNPs, we readily realize the long-term and real-time observation of the behaviors of the gene carriers in live cells (e.g. cellular uptake, intracellular trafficking). Most significantly, for the first time, interaction between the gene vectors and lysosome is readily observed through tracking strong and stable fluorescence of the SiNPs, revealing an interesting gene carrier-lysosome "re-fusion" phenomenon. Furthermore, by using human breast cancer cells (MCF-7 cells) with GTE value of?16% as a control, more "re-fusion" times (i.e., 3) are observed compared to that (1) of HeLa cells.In summary, we herein present a novel kind of fluorescent SiNPs-based nanocarriers, which simultaneously feature simultaneously feature strong and stable fluorescence, favorable biocompatibility, as well as high DNA loading capacity and gene transfection efficiency. Furthermore, the unique optical properties of SiNPs allow real-time and long-term tracking intracellular behaviors of gene carriers in live cells. These results suggest the fluorescent and photostable SiNPs-based gene carriers as a new kind of high-performance gene vectors in the field of gene therapy, and provide invaluable information for understanding intracellular behaviors of gene carriers.