Preparation of Poly[lactic-co-glycolic] Acid Nanospheres and Its Role in Hepatoma Cells.

Poly[lactic-co-glycolic] acid (PLGA) targeting nanoparticles AFP/PLGA/Dt, loaded with Dt plasmid of diphtheria toxin gene, modified by Alpha fetoprotein (AFP) monoclonal antibody, is prepared. Its physical and chemical properties and its effect on HepG2 cells are studied. Firstly, Dt expression plasmid pET11a/Dt is constructed and PLGA nanoparticles are prepared by emulsion solvent evaporation (ESE). Scanning electron microscope (SEM) is used to observe its morphology. Laser Particle Sizer is used to measure the particle size. In addition, the encapsulation efficiency, drug loading and release rate of PLGA nanoparticles are measured. Carboxy fluorescein and rhodamine fluorescein are used to double label IgG/PLGA/Dt and AFP/PLGA/Dt nanospheres, respectively, the entry of nanospheres into HepG2 cells are observed at 3 h and 12 h. The effect of AFP/PLGA/Dt nanospheres on the migration of HepG2 cells is examined by wounding healing assay. Transwell chamber experiment is used to detect the effect of AFP/PLGA/Dt nanospheres on the invasion of HepG2 cells. MTT method is utilized to determine the inhibitory activity of nanoparticles on HepG2 cell proliferation. After treated with IgG/PLGA/Dt and AFP/PLGA/Dt nanoparticles for 48 hours, flow cytometry is used to detect the apoptosis rate and cell cycle of HepG2 cells in each group. The results show that the prepared nanospheres have regular morphology, flat surface, average particle size of 265.72±12.46 nm, zeta potential of -18.15 mV. The average entrapment efficiency and drug loading are 78.48±1.71% and 3.16±0.35%, respectively. The nanoparticles release slowly and stably . At the 10th day, the release rate reaches 75.13%. PLGA nanospheres can effectively protect DNA from nuclease degradation. The results show that AFP/PLGA/Dt nanospheres have biological targeting effect and can be enriched in cells. AFP/PLGA/Dt nanoparticles can significantly inhibit the migration, invasion and proliferation of HepG2 cells, and promote apoptosis.