Preparation And Surface-functionalization Of Core-shell Dye Nanoparticles And Their Bio-applications

In vivo near-infrared (NIR) fluorescence imaging technique is highly desirable forsensitive cancer early detection. Recently, organic dye nanoparticles have been widelyused in bioimaging and have made great success. However, organic dye nanopaticlesalso have some disadvantages, such as weak photostability and hard functionalization.Core-shell fluorescent nanoprobes integrating the excellent characteristics of core andshell materials have shown a very outstanding application effect. Through a largenumber of literature investigation and in-depth analysis, we introduce the core-shellstructure to dye nanoparticles system, our main results are listed as below:1、We developed novel silica-coated dye nanoparticles (NPs) as highly bright andultrastable near-infrared (NIR) fluorescent probe for long-term cellular imaging andultrasensitive in vivo animal imaging. With C18PMH-PEG modification, thesilica-coated dye NPs exhibited favorable biocompatibility, robust pH stability (pH2-10). The quantum yield (QY) of the core-shell NPs was increased about5%. Thesilica-coated dye NPs maintained a strikingly bright and stable fluorescence signalduring120min continuous laser irradiation. Applications of the core-shell NPs in highefficiency in vivo and ex vivo imaging were successfully demonstrated. With theexposure time was reduced to15ms, intense fluorescent signals can be distinctly,selectively and spatially resolved in tumor sites. The results of histology, biochemistryand hematology assay assessment indicated negligible in vivo toxicity for thesilica-coated dye NPs. The totality of results clearly demonstrates the exciting potentialof the NPAFN@SiO2NPs as a NIR fluorescent probe for long-term cellular imaging andultrasensitive in vivo imaging. 2、We fabricated a novel type of folate targeted core-shell dye nanoparticles asfluorescent probe for long time and real time cellular imaging. First, core-shell silicacoated dye nanoparticles were prepared by the previously reported method. Secondly,FA molecules were covalently attached to (3-aminopropyl) triethoxysilane (APTES) inthe presence of N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride (EDC).The product is denoted as APTES-FA. Subsequently, we modified the surface ofcore-shell dye nanoparticle with APTES-FA. Confocal fluorescence microscopy imagesindicated that the FA modified dye nanoparticles have higher cellular uptake. Then, wetake it as the probe to observe the behavior of live tumor cells. We have seen thedynamic cellular uptake and cell divivion. These results have certain guidingsignificance for us understanding cellular uptake and intracellular movementmechanism.