A modified spontaneous emulsification solvent diffusion method for the preparation of curcumin-loaded PLGA nanoparticles with enhanced in vitro anti-tumor activity

To improve the anti-tumor activity of hydrophobic drug curcumin, we prepared curcumin-loaded PLGA nanoparticles （PLGA-Cur NPs） through a modified spontaneous emulsification solvent diffusion （modified-SESD） method. The influence of main preparation parameters was investigated, such as the volume ratio of binary organic solvents and the concentration of surfactant. Results indicated that the synthesized regular spherical PLGA NPs with the average diameter of 189.7 nm exhibited relatively higher yield （58.9%）, drug loading （11.0% （w/w）） and encapsulation efficiency （33.5%）, and also a controllable drug release profile. In order to evaluate the in vitro cytotoxicity of the prepared NPs, MTT assay was conducted, and results showed that the NPs could effectively inhibit HL60 and HepG2 cells with lower IC50 values compared with free curcumin. Furthermore, confocal microscopy together with flow cytometry analysis proved the enhanced apoptosis-inducing ability of PLGA-Cur NPs. Polymeric NP formulations are potential to be used for hydrophobic drug delivery systems in cancer therapy.

Tumor-suppressor effects of chemical functional groups in an in vitro co-culture system

Liver normal cells and cancer cells co-cultured on surfaces modified by different chemical functional groups, including mercapto （-SH）, hydroxyl （-OH） and methyl （-CHz） groups. The results showed that different cells exhibited changes in response to different surfaces. Normal cells on -SH surface exhibited the smallest contact area with mostly rounded morphology, which led to the death of cancer cells, while cancer cells could not grow on -CH3 groups, which also died. In the co-culture system, the -CH3 group exhibited its unique effect that could trigger the death of cancer cells and had no effects on normal cells. Our findings provide useful information on strategies for the design of efficient and safe regenerative medicine materials.

Polyethyleneimine-modified calcium carbonate nanoparticles for p53 gene delivery

In this study,calcium carbonate(CaCO3)nanoparticles with spherical structure were regulated by arginine and successfully synthesized via a facile co-precipitation method.The average particle size of as-prepared CaCO3 was about 900 nm.The properties of nanostructured CaCO3 particles were characterized by scanning electron microscope,Fourier transform infrared spectroscopy,Xray diffraction and size distribution.After modified with polyethyleneimine(PEI),the ability of PEICaCO3 nanoparticles to carry GFP-marked p53 gene(pEGFP-C1-p53)into cancer cells to express P53 protein were studied.Meanwhile,the cytotoxicity,transfection efficiency,cells growth inhibition and the ability to induce apoptosis by expressed P53 protein were conducted to evaluate the performances of PEI-CaCO3 nanoparticles.The results show that prepared PEI-CaCO3 nanoparticles had good biocompatibility and low cytotoxicity in a certain concentration range.PEI-CaCO3 effectively transfected pEGFP-C1 gene into epithelial-like cancer cells.And with the expression of GFP-P53 fusion protein,pEGFP-C1-p53-gene-loaded PEI-CaCO3 particles significantly reduced the proliferation of cancer cells.These findings indicate that our PEI-modified CaCO3 nanoparticles are potential to be successfully used as carriers for gene therapy.