Study On The Preparation Of Multi Functionlized Nanoparticles And Their Glioma-targeting Activities In Vitro

Biotinylated PEG-PLA (Biotin-PEG-PLA) block copolymer was synthesized by copolymerizing D,L-lactide with biotinylated PEG (Bitoin-PEG) via ring-opening polymerization with Sn(Oct)2 as the catalyst and Bitoin-PEG as the reaction initiator, in which Bitoin-PEG was firstly prepared by esterifying the hydroxyl groups of PEG with biotinyl chloride.The copolymer was characterized by 1H-NMR. Biotin-PEG-PLA nanoparticles were prepared via nanoprecipitation, and their mean diameter and morphology were characterized by transmission electron microscope and dynamic laser scattering, respectively. The results showed that the Biotin-PEG-PLA nanoparticles were mostly in the shape of spheres with the size less than 100nm.The biofunctionalization of Biotin-PEG-PLA nanoparticles based on Avidin-Biotin interaction was performed by using transferrin and/or RGD as functional protein/peptide. The concentrations of transferrin or RGD bonded to Biotin-PEG-PLA nanoparticles were evaluated by UV-spectrophotometer.The uptakes of bare Biotin-PEG-PLA nanoparticles, Tf founctionalized Biotin-PEG-PLA nanoparticles, RGD founctionalized Biotin-PEG-PLA nanoparticles and double founctionalized Biotin-PEG-PLA nanoparticles by U251 tumor cells in vitro were investigated via fluorescence microscopy to evaluate the target activities of the above mentioned nanoparticles. Both the results of fluorescence microscopy and flow cytometry suggested that the delivery rate of the founctionalized Biotin-PEG-PLA nanoparticles into the U251 cells werehigher than that of bare nanoparticles; while the double founctionalized nanoparticles exhibited the highest rate, indicating that Biotin-PEG-PLA nanoparticles after biofunctionalization showed glioma cell targeting ability.