Three-dimensional culture and clinical drug responses of a highly metastatic human ovarian cancer HO-8910PM cells in nanofibrous microenvironments of three hydrogel biomaterials.

BACKGROUND: Ovarian cancer is a highly aggressive malignant disease in gynecologic cancer. It is an urgent task to develop three-dimensional (3D) cell models in vitro and dissect the cell progression-related drug resistance mechanisms in vivo. In the present study, RADA16-I peptide has the reticulated nanofiber scaffold networks in hydrogel, which is utilized to develop robust 3D cell culture of a high metastatic human ovarian cancer HO-8910PM cell line accompanied with the counterparts of Matrigel and collagen I. RESULTS: Consequently, HO-8910PM cells were successfully cultivated in three types of hydrogel biomaterials, such as RADA16-I hydrogel, Matrigel, and collagen I, according to 3D cell culture protocols. Designer RADA16-I peptide had well-defined nanofiber networks architecture in hydrogel, which provided nanofiber cell microenvironments analogous to Matrigel and collagen I. 3D-cultured HO-8910PM cells in RADA16-I hydrogel, Matrigel, and collagen I showed viable cell proliferation, proper cell growth, and diverse cell shapes in morphology at the desired time points. For a long 3D cell culture period, HO-8910PM cells showed distinct cell aggregate growth patterns in RADA16-I hydrogel, Matrigel, and collagen I, such as cell aggregates, cell colonies, cell clusters, cell strips, and multicellular tumor spheroids (MCTS). The cell distribution and alignment were described vigorously. Moreover, the molecular expression of integrin ß1, E-cadherin and N-cadherin were quantitatively analyzed in 3D-cultured MCTS of HO-8910PM cells by immunohistochemistry and western blotting assays. The chemosensitivity assay for clinical drug responses in 3D context indicated that HO-8910PM cells in three types of hydrogels showed significantly higher chemoresistance to cisplatin and paclitaxel compared to 2D flat cell culture, including IC50 values and inhibition rates. CONCLUSION: Based on these results, RADA16-I hydrogel is a highly competent, high-profile, and proactive nanofiber scaffold to maintain viable cell proliferation and high cell vitality in 3D cell models, which may be particularly utilized to develop useful clinical drug screening platform in vitro.

Synthesis of La-Co-O Mixed Oxides via Polyethylene Glycol-Assisted Co-Precipitation Method for Total Oxidation of Benzene.

La-Co-O mixed oxides (LCO) were prepared by co-precipitation method with the presence of polyethylene glycol (PEG) as dispersant. The influence of adding different molecular weight of PEG (0, 2 000, 6 000, 20 000 g·mol-1) on the physicochemical and catalytic properties of La-Co-O mixed oxides for total oxidation of benzene was investigated. The samples were characterized by means of N2 physical adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature-programmed reduction by H2 (H2-TPR), temperature-programmed desorption of O2 (O2-TPD), and X-ray photoelectron spectroscopy (XPS). The order of catalytic activity was found to be LCO-PEG6000>LCO>LCO-PG20000>LCO-PG2000. Particularly, LCO-PEG6000 exhibited benzene conversion of 99% at temperature as low as 383 ℃, which was 126 ℃ lower than that of LCO. The characterization result reveals that all samples had a BET surface area of about 9～10 m2·g-1. The XRD result shows that on all samples LaCoO3 perovskite was mainly formed together with a small amount of La2O3 and Co3O4. The addition of PEG was favorable for the formation of LaCoO3 perovskite. Particularly, the addition of PEG-6000 effectively suppressed the agglomeration of LaCoO3 perovskite, giving rise to small and uniform particles as observed by SEM. Moreover, the results of H2-TPR and O2-TPD indicate that the obtained La-Co-O mixed oxides showed higher reducibility and lattice oxygen mobility, and the Co 2p XPS analysis suggests that more surface Co3+ active species were presented by the addition of PEG-6000. These properties are thought to contribute to the high activity in benzene total oxidation.

[Determination of palladium in automobile exhaust catalysts by FAAS method].

Palladium in automotive exhaust catalyst was determined by flame atomic absorption spectrometry (FAAS). The analytical conditions and the coexisting elements interference were studied. The catalyst was dissolved by the mixture of H2O2 and HCl. Pd in the solution was directly determined by FAAS method. The linearity of working curve ranges from 0.1 to 15 microg x mL(-1); the detection limit is 0.029 microg x mL(-1); the relative standard deviation (RSD) range is from 0.8% to 2.5%; and the recovery rate range is from 99.6% to 101.2%. It is a simple and convenient method for accurate analysis of Pd in the exhaust catalysts.

[Effects of pH value during synthesis on the structure and performance of ceria zirconia mixed oxides].

Heating reflux aging technology was first applied to obtain a series of ceria zirconia mixed oxides composed of 0.6CeO2-0.4ZrO2. N2 physical adsorption, FT-Raman, and UV-Vis diffuse spectroscopy techniques were preformed to investigate the relationships between the structure and oxygen storage capacity of ceria zirconia mixed oxides prepared at different pH value of precipitation. The composition of ceria zirconia mixed oxides fluctuated with the pH value of precipitation, leading to the variation in phase ingredients, defects, crystallization and texture. Controlling the pH value of precipitation at 10.5-11.0 can avoid the introduction of Si, improve the texture, phase homogeneity and defects concentration, decrease the degree of crystallization, and increase the oxygen storage capacity.

[The relationship between structure and oxygen storage capacity of Ce(x)Zr(1-x)O2 solid solution].

Heating reflux aging technology was applied to prepare a series of Ce(x)Zr(1-x)O2 (0.25 < or = x < or = 1) solid solution. The effects of the Ce(x)Zr(1-X)O2 composition on the structure and oxygen storage capacity were characterized using N2 physical adsorp tion, X-ray diffraction (XRD), FT-Raman, UV-Vis diffuse spectroscopy techniques. The texture, structure and thermal stability of ceria-zirconia mixed oxides are closely related to the ratio of cerium to zirconium in the solid solution, with increasing the zirconium content, the specific area increases, and the structure undergoes a change of order --> disorder --> order. Among them, Ce(0.4Zr(0.6)O2 sample possesses the maximum OSC and Ce(0.25)Zr(0.75)O2 sample possesses the best thermal stability.

The effects of self-assembling peptide RADA16 hydrogel on malignant phenotype of human hepatocellular carcinoma cell.

The aim of this study will provide a self-assembling peptide (RADA16-I) -derived hydrogel as a tool for investigation the malignant phenotype of human hepatocellular carcinoma cell. Characteristic analysis indicated that the peptide consists of a well-defined secondary structure and self-assembly property. Our results showed that these cells cultured in RADA16-I hydrogels showed a spindle-shaped phenotype with irregular and radial nuclei. Immunohistochemical results showed that the expression of fibronectin in hepatocellular carcinoma cells is positive cultured in RADA16-I hydrogels, and the expression levels of laminin are weakly positive. DNA contents cultured in RADA16-I hydrogel gradually increased up to Day 9. The expression levels of VEGFA, EGF and FGF2 in three hydrogels showed no statistically significant differences (P > 0.05), and the expression levels of IGF-1 in RADA16-I and collagen-I were significantly lower than those of in the Matrigel hydrogel (P ≤ 0.05). These findings suggested that the RADA16-I will help to provide a better physiological substrate for hepatocellular carcinoma cell culture, may serve as an ideal model for cancer biology research of tumorigenesis, growth, local invasion, and metastasis.

[Study on the ultraviolet-visible spectra of Au/Al2O3 catalysts].

A variety of synthesis parameters for the preparation of gold nanoparticles by NaBH4 solution reduction in the W/O microemulsion media consisting of Cetyl Trimethyl Ammonium Bromide (CTAB)/n-hexanol/water system was investigated. The results showed that the molar ratio of water to surfactant (rw) had nothing to do with the gold particle size, but the concentration of the aqueous gold salt solution had a significant effect on the size of gold particle. Through optimizing the preparation parameters, Au/Al2O3 catalysts were prepared with two different methods, then the catalysts were characterized by ultraviolet-visible spectra, XRD and TEM, and the effect of two different preparation methods on active component gold particle size in the catalysts was studied.

[Diffusion reflectance spectroscopy of ZrO2 phase structure].

Diffusion Reflectance Spectroscopy (DRS) was employed to study the surface phase structure of ZrO2-based catalysts. The effect of calcining temperature, and the addition of Al2O3 and platinum on the surface and bulk phase structures of zirconia was studied by DRS combined with XRD, DTA and XPS. The same trend was observed that heating to higher temperatures results in the conversion to monoclinic zirconia in undoped samples, while incorporation of an appropriate amount of Al2O3 would stabilize the tetragonal phase zirconia. And the reduction processing of Pt/ZrO2 affects crystallization and phase transitions, resulting in certain fraction of tetragonal ZrO2 transferred to monoclinic ZrO2. The DRS shows an appreciable difference in the corresponding XRD spectra that more monoclinic zirconia formed on the surface of catalyst during the reduction processing of Pt/ZrO2, compared to the bulk of catalyst.