Xiangdong Kong

Calcium carbonate microparticles used as a gene vector for delivering p53 gene into cancer cells.

Calcium carbonate (CaCO(3) ) microparticles were for the first time used for efficient delivery of p53 gene to transfect human cancer cells HeLa. CaCO(3) microparticles (2-4 μm) absorbed pEGFP-C1-p53 (expressing GFP-P53 fusion protein) to transfect HeLa cells. Flow cytometer (FCM) was used to evaluate the gene transfection efficiency in HeLa cells, which were stably transduced with a green fluorescent protein gene. In this study, CaCO(3) delivering pEGFP-C1-p53 could transfect about 5% of the tumor cells in culture. However, the efficiency of tumor cell apoptosis was surprisingly up to 80%. Meanwhile, the results of MTT assay and crystal violet staining showed that the CaCO(3) microparticles had low cytotoxicity. These findings showed that CaCO(3) microparticles were perspective to be used as new vectors for gene therapy.

The anti-tumor effect of p53 gene-loaded hydroxyapatite nanoparticles in vitro and in vivo

This research focused on anti-tumor effect of pEGFP-C1-p53 (p53) gene-loaded hydroxyapatite (HAp) nanoparticles in vitro and in vivo. Four kinds of HAp nanoparticles, spherical HAp nanoparticles (S-HAp, diameter: 50xa0nm), needle-like HAp nanoparticles (N-HAp, average length: 110xa0nm and width: 30xa0nm), rod-like HAp nanoparticles (R-HAp, average length: 100xa0nm and width: 30xa0nm), and short-rod-like HAp nanoparticles (SR-HAp, average length: 40xa0nm and width: 30xa0nm), were prepared initially. The HAp nanoparticles with or without being modified by PEI (named HAp and HAp-PEI, respectively) have excellent biocompatibility as shown by MTT assay and crystal violet staining tests. Then, the subsequent MTT, Hocehst staining tests, and Western blot showed that the killing effect of p53-loaded HAp-PEI (HAp-PEI-p53) was effective with fair selectivity toward Hep-3B and HuH-7 cells’ cell lines. Moreover, HAp-PEI-p53 could inhibit the tumor growth in vivo, and the mechanism of tumor growth inhibition was verified by the hematoxylin and eosin staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, P53 protein immunohistochemistry, and transmission electron microscope of the tumor cell in vivo. We found that HAp-PEI-p53 has good anti-cancer effect in vitro and in vivo, especially for the S-HAp-PEI-p53. Tumor metastasis could be suppressed significantly by the S-HAp-PEI-p53 and N-HAp-PEI-p53 treatments by the in vivo imaging system. All these results lead to the conclusion that the particle sizes of HAp ranging from 100 to 200xa0nm are appropriate for cancer gene therapy and may be widely used in anti-cancer investigation.

Effect of silk sericin on morphology and structure of calcium carbonate crystal

In this paper, silk sericin was employed to regulate the mineralization of calcium carbonate (CaCO3). CaCO3 composite particles were prepared by the precipitation reaction of sodium carbonate with calcium chloride solution in the presence of silk sericin. The as-prepared samples were collected at different reaction time to study the crystallization process of CaCO3 by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The results showed that silk sericin significantly affected the morphology and crystallographic polymorph of CaCO3. With increasing the reaction time, the crystal phase of CaCO3 transferred from calcite dominated to vaterite dominated mixtures, while the morphology of CaCO3 changed from disk-like calcite crystal to spherical vaterite crystal. These studies showed the potential of silk sericin used as a template molecule to control the growth of inorganic crystal.

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.

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 900u2009nm. The properties of nanostructured CaCO3 particles were characterized by scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction and size distribution. After modified with polyethyleneimine (PEI), the ability of PEI-CaCO3 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.

Towards understanding the distribution and tumor targeting of sericin regulated spherical calcium phosphate nanoparticles

The study of calcium phosphate (CaP) nanoparticles in vivo is still incomplete, which has limited their applications for biomedical delivery. Herein, we synthesized amorphous spherical calcium phosphate (S‐CaP) nanoparticles with an average size of 80 nm via a co‐precipitation method in the presence of silk sericin as the regulation template. S‐CaP was labeled by the near‐infrared dye reagent DiR, and then, the labeled nanoparticles (S‐CaP@DiR) were used to investigate the distribution and degradation in healthy mice by IVIS and TEM. The results showed that the S‐CaP nanoparticles were mainly distributed in the liver, and ∼90% of them (500 μg) could be degraded by the liver within 2 weeks. Tumor‐bearing mice were then prepared, and the S‐CaP was injected intravenously. Strikingly, the nanoparticles can effectively target solid tumors in cancer cell‐bearing mice, indicating that the solid tumor was a foundation for the enrichment of the nanoparticles by the EPR effect, which showed the important potential of biodegradable inorganic nanoparticles in clinical drugs for tumor therapy.

Glioma cell line proliferation controlled by different chemical functional groups in vitro

Glioma cell line C6 cultured on silicon surfaces modified by different chemical functional groups, including mercapto (-SH), carboxyl (-COOH), amino (-NH2), hydroxyl (-OH) and methyl (-CH3) groups, was studied here to investigate the influence of surface chemistry on the cell proliferation, adhesion and apoptosis. AFM confirmed the similar characteristic of different functional groups occupation. The adhering C6 exhibited morphological changes in response to different chemical functional groups. The C6 adhered to -COOH, -NH2, -OH and -CH3 surfaces and flattened morphology, while those on -SH surface exhibited the smallest contact area with mostly rounded morphology, which led to the death of cancer cells. The results of MTT assay showed that the -COOH and -NH2 groups promoted cell proliferation, while the -SH significantly inhibited the proliferation. Compared with other chemical functional groups, the -SH group exhibited its unique effect on the fate of cancer cells, which might provide means for the design of biomaterials to prevent and treat glioma.

Towards understanding the distribution and tumor targeting of sericin regulated spherical calcium phosphate nanoparticles: Zhao et al.

The study of calcium phosphate (CaP) nanoparticles in vivo is still incomplete, which has limited their applications for biomedical delivery. Herein, we synthesized amorphous spherical calcium phosphate (S‐CaP) nanoparticles with an average size of 80 nm via a co‐precipitation method in the presence of silk sericin as the regulation template. S‐CaP was labeled by the near‐infrared dye reagent DiR, and then, the labeled nanoparticles (S‐CaP@DiR) were used to investigate the distribution and degradation in healthy mice by IVIS and TEM. The results showed that the S‐CaP nanoparticles were mainly distributed in the liver, and ∼90% of them (500 μg) could be degraded by the liver within 2 weeks. Tumor‐bearing mice were then prepared, and the S‐CaP was injected intravenously. Strikingly, the nanoparticles can effectively target solid tumors in cancer cell‐bearing mice, indicating that the solid tumor was a foundation for the enrichment of the nanoparticles by the EPR effect, which showed the important potential of biodegradable inorganic nanoparticles in clinical drugs for tumor therapy.

Towards understanding the distribution and tumor targeting of spherical calcium phosphate nanoparticles

The study of calcium phosphate (CaP) nanoparticles in vivo is still incomplete, which has limited their applications for biomedical delivery. Herein, we synthesized amorphous spherical calcium phosphate (S‐CaP) nanoparticles with an average size of 80 nm via a co‐precipitation method in the presence of silk sericin as the regulation template. S‐CaP was labeled by the near‐infrared dye reagent DiR, and then, the labeled nanoparticles (S‐CaP@DiR) were used to investigate the distribution and degradation in healthy mice by IVIS and TEM. The results showed that the S‐CaP nanoparticles were mainly distributed in the liver, and ∼90% of them (500 μg) could be degraded by the liver within 2 weeks. Tumor‐bearing mice were then prepared, and the S‐CaP was injected intravenously. Strikingly, the nanoparticles can effectively target solid tumors in cancer cell‐bearing mice, indicating that the solid tumor was a foundation for the enrichment of the nanoparticles by the EPR effect, which showed the important potential of biodegradable inorganic nanoparticles in clinical drugs for tumor 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 (-CH3) 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.