Advanced Materials Research Vols. 750-752

Abstract: In this paper, Fe-OCAP/PU blends were prepared. The mechanical properties and thermal stability of the samples were studied by tensile tests and thermogravimetric analysis, respectively. Results showed that the mechanical properties and thermal stability of the samples were improved with the increase of Fe-OCAP content. The antibacterial property of Fe-OCAP and Fe-OCAP/PU films was investigated by agar diifusion method and shake flask method, respectively. Fe-OCAP and Fe-OCAP/PU films showed efficient antibacterial activity against S.aureus.

Abstract: A method based on capillary electrophoresis with electrochemical detection was developed for the determination of polyphenols in Lycopus Lucidus Turcz. Operated in a wall-jet configuration, a 300 μm diameter carbon-disk electrode was used as the working electrode. Under the optimum conditions, the targeted analytes, i.e. rutin, chlorogenic acid, apigenin, luteolin and quercetin were baseline separated within 25 min in a 60mmol/L borate buffer (pH 9.0). Notably, excellent linearity was obtained over three orders of magnitude with detection limits (S/N=3) ranging from 1×10^-7 g/mL to 1×10^-6 g/mL for all analytes.

Abstract: Propolis is a resinous substance collected by honeybees from leaf buds and cracks in the bark of various plants, the pharmacologically active components in the propolis are flavonoids and phenolic acids and their esters. A simultaneous determination of flavonoids and phenolic acids from propolis and its medicinal preparations by capillary electrophoresis with electrochemical detection (CE-ED) was reported. Under the optimum conditions, the analytes could be separated in a 100 mmol/l borate buffer (pH=8.7) within 25 min. The response was linear over three orders of magnitude with detection limit (S/N=3) ranging from 1×10^-7 g/ml to 5×10^-7 g/ml for the analytes. This method has been used for the determination of flavonoids and phenolic acids from propolis and its medicinal preparations, and the assay result was satisfactory.

Abstract: The purpose of this study was to isolate citral from sweet orange oil by combined usage of molecular distillation and column chromatography. Additionally, the antioxidant activity (by DPPH radical scavenging activity and reducing power) of citral was evaluated. A significant and linear correlation coefficient between the antioxidant activity and the concentration of citral was found (R2=0.9925). On the other hand, the cytotoxic effects of the citral against tumoral human cell line Hela was examined by MTT assay and the IC50 values was 32.56 μg/mL. Overall, results presented here suggest that the citral possesses antioxidant activity and cytotoxic properties, and is a potential source of active ingredients for food and pharmaceutical industry.

Abstract: In this paper, plasma acid was obtained by treating distilled water with dielectric barrier discharge at atmospheric pressure in order to hydrolyze cellulose. The acidity of plasma acid was studied through a single factor experiment. A plasma acid with pH value of 1.42 was obtained and used to hydrolyze microcrystalline cellulose at 80°C for 60min. Under this condition, the integrated optical density (IOD) of the hydrolysis sample was 0.589. Based on standard glucose curve, the total reducing sugar (TRS) was calculated to be 53.75mg and the TRS yield was 53.75%. The filtrate was evaporated to get the solid hydrolysis sample to be analyzed by High-performance liquid chromatography (HPLC). The results showed that the sample mainly consisted of glucose, which proved that microcrystalline cellulose could be hydrolyzed by plasma acid. Therefore, it could be concluded that it was an environmentally friendly and economical method to hydrolyze the microcrystalline cellulose by plasma acid.

Abstract: In this paper, we reported the dynamic self-assembly process of an half-sequence ionic self-complementarity peptide CH₃CO-Pro-Ser-Phe-Cys-Phe-Lys-Phe-Glu-Pro-NH₂, which could self-assemble into stable nanofibers and formed hydrogel consisting of >99% water. The dynamic self-assembly process was detected by circular dichroism (CD) and atomic force microscopy (AFM). CD spectrum revealed that the mainly contents of the peptide were regular β-sheet structure. The data indicated that though the secondary structure of the peptide formed immediately, the microstructure of the self-assembly process of the designed peptide formed slowly. AFM image illustrated that the self-assembly process was layer-by-layer assembly.

Abstract: Lamellar inorganic materials such as MMT and LDH are expected to improve swelling-deswelling behavior and fatigue property of CS. In this study, laminated hydroxyapatite (HAp)/ chitosan (CS) composite hydrogels with different HAp contents (0, 1%, 2%, 3%) were prepared by means of solution intercalation in this paper. Swelling/deswelling test indicates that 3HAp/CS hydrogel shows the best swelling/deswelling property which is ideal for large drug loading and slow drug release. The intercalated strucure of 3HAp/CS hydrogel was confirmed by TEM investigation.

Abstract: Luminescent Ln³⁺ (Ce³⁺, Tb³⁺) doped hydroxyapatite (HAp: Ce, Tb) phosphors were successfully fabricated via the modified hydrothermal process. The structure, morphology, and luminescent properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectra respectively. The XRD results reveal that the obtained HAp: Ce, Tb phosphors show the characteristic peaks of hydroxyapatite in a hexagonal lattice structure and the import of Ce³⁺and Tb³⁺ causes small change in the crystalline structure and leads to the peaks shifting and declining. It is observed that the as-prepared luminescent samples exhibit nearly equiaxial morphology of dispersed particles about 50-150 nm in size. Under 254 nm UV radiation excitation, the phosphors demonstrate the characteristic ⁵D₄⁷F₃₆ emission lines of Tb³⁺and the excitation of Tb³⁺ is mainly caused by the energy transfer from Ce³⁺. PL intensity of Tb³⁺ doped HAp remarkably strengthened with increment of Ce³⁺ concentration and reached the maximum at the concentration of 4 mol%.

Abstract: Purpose A biodegradable PEG-PLGA nanoparticle (NP) modified by transferrin (Tf) was conceived. Doxorubicin (Dox), a widely used antitumor agent, without passing through the BBB, which limited its utility on glioma, was encapsulated inside (Tf-NP-Dox). Furthermore, its therapeutic efficacy to glioma was evaluated both in vitro and in vivo. Methods Tf-NP-Dox was prepared via modified single emulsion method. Its characterization including size, Drug loading capacity (DLC), entrapment efficiency (EE), Tf number on Tf-NP-Dox surface were estimated. The antitumor efficiency in vitro was evaluated via MTT assay. The transmembrane transportation was evaluated via HPLC assay. The antitumor efficiency in vivo was assessed on C6 glioma intracranial implant rats model. Results The average diameter of Tf-NP-Dox is around 200 nm with surface Tf molecule number per Tf-NP-Dox approximately 25. MTT assay demonstrated stronger cytotoxicity of Tf-NP-Dox to C6 glioma cells (P<0.01). HPLC assay showed Tf-NP-Dox transport Dox into C6 with higher efficiency compare to NP-Dox or Dox (P<0.01). On C6 glioma bearing rat, Tf-NP-Dox could transport more Dox into tumors tested by HPLC assay (P<0.05), and extended life span markedly compared to NP-Dox or Dox (P<0.05). Conclusions Tf-NP-Dox had a potential of glioma targeting and had a better therapeutic effect to glioma both in vitro and in vivo.

Abstract: Mesoporous bioactive glass (MBG) has superior bioactivity and degradation than non-mesoporous bioactive glass (BG) in vitro. But the biological effect of MBG in vivo is still unknown. In this study, MBG powders with 20μm were implanted into the femoral condyles in SD rats. BG powders with 20μm were used as a control. The local degradation and osteogenesis were observed at 1 week and 4 weeks after implantation, and the systemic toxicity of the degradation products were also evaluated simultaneously. The results revealed MBG powders had the faster rate of degradation and better osteogenesis effect than BG powders at 4 weeks, although the most of material still remained in situ. Histopathological analyses indicated the degradation products did not have any damage to major organs such as liver and kidney. In conclusion, this preliminary study demonstrated that MBG powders have more excellent biological effect at 4 weeks than that of BG in vivo. However the long-term effect needs to be confirmed.