Preparation And Bio-application Of Carrier-free Organic Fluorescent Nanoprobes And Nanodrugs

With the development of nanotechnology, it appears various nanocarriers which loading dyes or anti-cancer drugs, such as liposomes, micelles, dendrimer and so on. After wrapped into nanocarrier, the stability of dyes or anti-cancer drugs against the outer environment can be greatly enhanced. However, the loading capacity is low because of the high proportion of carrier.Based on the above problems, we prepare carrier-free organic fluorescent nanoprobes and nanodrugs, the main studies are listed as follows:1. We report a type of organic dye nanoparticles with coating of a thin silica layer and folic acid targeting molecules on the surface(NPAPF@SiO2-FA NPs) for live cell imaging. These organic nanoparticles possess superior characteristics of high fluorescence intensity, large Stokes shift, good photostability, emission in the NIR range, and targeted delivery, enabling them to be a powerful fluorescent probe for living cell imaging. In our study, we successfully demonstrate their applications in investigating cell division, exploring the cellular uptake kinetics and pathway of NPs, observing the distribution of NPs, and live-time tracking the trajectory of specific NPs. The major advantage of as-prepared NPAPF@SiO2-FA NPs is that these nanostructures enter cells via clathrin- and caveolae-independent endocytosis pathway. This leads to improved intracellular uptake and prolonged stay within cells and correspondingly enhanced fluorescence intensity. We expect that this type of organic dye NPs will play an important role in live cell imaging.2. We have demonstrated a simple strategy of preparation of carrier-free Pt(IV) prodrug nanoparticles for drug delivery. C18PMH-PEG was used to modify the material and this led the nanostructures to be water-dispersible and size stable. The in vitro anticancer efficacy showed that the toxicity of Pt(IV) NPs was higher than cisplatin for long time observation. Pt(IV) NPs were internalized into cells through clathrin and caveolae- dependent pathway, which changed the internalization pathway of cisplatin. To some extent, it could overcome the problem of multidrug resistance. After internalized into cells, Pt(IV) NPs could be captured by lysosomes and followed by the release of free Pt(IV). Pt(IV) complexes were then reduced to cisplatin for cancer therapy. The as-prepared high drug loading based delivery system exhibited obvious advantages than the conventional nanodrug delivery system.