Construction And Evaluation Of PLGA/O-CMC Nanoparticles As Composite Functional Delivery System For Anticancer Drugs And Genes

The traditional double emulsion (water-in-oil-in-water) method to preparehydrophilic drug-loaded nanoparticles (NPs) was modified and improved to getsmaller NPs and high encapsulation efficiency of drug; Poly (D, L-lactide-co-glycolicacid) (PLGA) and o-carboxymethyl chitosan (O-CMC) were chosen tomicroencapsulate 5-fluorouracil (5-FU) and antisense-EGFR cDNA by improvedW/O/W method due to their attractive degradation and physicochemical properties;So 5-FU and antisense-EGFR-loaded PLGA/O-CMC NPs were created to realize thecombination of anticancer drug and gene in one kind of biodegradable nanocarrier. The results of characterizing all kinds of nanoparticles showed that: (1) meansize of O-CMC-coated PLGA NPs without drug is 222.9nm, polydispersity is 0.109,Zeta potenial is 73.46eV, N percentage on the surface of NPs is 10.3%, hydrophilicityof NPs is very good; (2)mean size of 5-FU-coated PLGA/O-CMC NPs is 98.5nm,polydispersity is 0.192, Zeta potenial is 61.48eV, N percentage on the surface of NPsis 12.2%,5-FU-loading level is 18.9%; (3) mean size of antisense-EGFR-encapsulatedPLGA/O-CMC NPs while absorbing antisense-EGFR is 375.3nm, polydispersity is0263, Zeta potenial is –10.67eV. SEM was used to study the morphological change of NPs during degradation, andweight loss of NPs and pH change of degradation medium were traced. Researches of5-FU release behavior from NPs showed that (1) release kinetics of 5-FU from NPs inearly 12 hours was coincidence with Huguchi release; (2)release kinetics in 20 dayswas coincidence with Zero-level release. Release kinetics ofantisense-EGFR-encapsulated PLGA/O-CMC NPs while absorbing antisense-EGFRwas accordance with Zero-level release. Cell viability in vitro as well as in vivo demonstrated that biocompatibility ofPLGA/O-CMC NPs was good. Results of MTT and cell apoptosis illustrated that both5-FU-encapsulated NPs and antisense-EGFR-loaded NPs had high cytotoxicity onbrain tumor cells TJ905, and immunohistochemical staining approved thatantisense-EGFR-loaded NPs had inhibitory effect on the expression of EGFR ofhuman gliomas cells. Fluorescence microscope and confocal microscope were used totrace the procedures of cell transfection induced by NPs. It was found that there weresome NPs were in nucleus after 24h. Both 5-FU and antisense-EGFR-encapsulated NPs while absorbing EGFR on thesurface of NPs designed by us creatively had high antisense-EGFR loading level andhigh cytotoxicity on gliomas cells (73.6%), which showed that 5-FU andantisense-EGFR had cooperation effect on the inhibitory effect of gliomas cells.