重组人骨形态发生蛋白2壳聚糖纳米微球的制备及体外细胞毒性

背景:通过各种微球负载骨生长因子使骨形态发生蛋白达到缓释效果逐渐成为研究热点,但关于载药壳聚糖纳米微球的生物相容性特别是细胞毒性的报道较少。目的:对重组人骨形态发生蛋白2壳聚糖纳米微球进行细胞毒性检测,评估应用壳聚糖纳米微球作为重组人骨形态发生蛋白2缓释载体的生物安全性。方法:通过离子交联法制备空白壳聚糖纳米微球,应用透视电镜观察微球的形态,激光粒径分析其粒径分布;通过重组人骨形态发生蛋白2壳聚糖纳米微球体外细胞毒性试验评估微球的生物安全性。结果与结论:离子交联法制备的壳聚糖微球,球形规整,分散均匀,微球平均粒径为230nm,分布较集中。载药及空白微球的反应分级为0或1级,均为合格。提示,离子交联法制备可成功制备出负载重组人骨形态发生蛋2的纳米微球,且微球细胞毒性检测合格,为进一步的骨组织工程研究提供理论实验基础。

Biocompatibility of vascular stents manufactured using metal injection molding in animal experiments

This study aimed to evaluate the feasibility and safety of a novel stent manufactured by metal injection molding(MIM)in clinical practice through animal experiments.Vessel stents were prepared using powder injection molding technology to considerably improve material utilization.The influence of MIM carbon impurity variation on the mechanical properties and corrosion resistance of 316L stainless steel was studied.In vitro cytotoxicity and animal transplantation tests were also carried out to evaluate the safety of MIM stents.The results showed that the performance of 316L stainless steel was very sensitive to the carbon content.Carbon fluctuations should be precisely controlled during MIM.All MIM stents were successfully implanted into the aortas of the dogs,and the MIM 316L stents had no significant cytotoxicity.The novel intravascular stent manufactured using MIM can maintain a stable form and structure with fast endothelialization of the luminal surface of the stent and ensure long-term patency in an animal model.The novel intravascular stent manufactured using MIM demonstrates favorable structural,physical,and chemical stability,as well as biocompatibility,offering promising application in clinical practice.

In vitro corrosion behavior and cytotoxicity property of magnesium matrix composite with chitosan coating

Mg-6%Zn-10%β-Ca3(PO4)2 composite was prepared through powder metallurgy methods with different chitosan coatings on its surface. The properties of the chitosan coatings on the surface of Mg-6%Zn-10%β-Ca3(PO4)2 composite, such as the adhesion ability, the corrosion behavior and the cytotoxicity properties, were investigated, and the microstructure of the chitosan coating was observed by scanning electron microscope(SEM). The results show that chitosan coating improves the corrosion resistance of the magnesium composite specimens significantly. Mg-6%Zn-10%β-Ca3(PO4)2 composite specimens exhibit good corrosion resistance and low p H values in simulated body fluid(SBF) at 37 °C in the immersion test with 7-layer chitosan coating whose relative molecular mass is 30×104 Da. The cytotoxicity tests indicate that Mg-6%Zn-10%β-Ca3(PO4)2 with chitosan coating is nontoxic with a cytotoxicity grade of zero against L-929 cells, which is better than that of uncoated composites.

In-vitro and In-vivo Anti-trypanosomal Activity of Terminalia chebula Retz Dried Fruits

African trypanosomosis had caused lots of havocs to both humans and animals over a century with successes and failure in curtailing it. This study was aimed at screening medicinal plant, Terminalia chebula dried fruits against Trypanosoma evansi for trypanocidal activity. Twenty grams of powdered Terminalia chebula dried fruits was cold extracted with methanol. Obtained MPE （methanolic plant extract） was in vitro tested against Trypanosoma brucei （1 × 10^6 trypanosomes/mL of the medium in each ELISA plate wells） at concentrations （250～1,000 μg/mL） on Vero cells grown in DMEM （Debecco＇s Modified Eagle Medium） in appropriate conditions for trypanocidal activity. In-vitro cytotoxicity test of MPE of Terminalia chebula was conducted on Vero cells grown in DMEM. In-vivo assay for trypanocidal activity, each mouse was inoculated with 1 × 10^4/mL of trypanosomes and treated （48 h post inoculation） with MPE of Terminalia chebula at concentrations （12.5, 25, 50, 100 and 200 mg/kg body weight） were administered at dose rate of 100 BL per mouse via intraperitoneal route to different groups of mice, 6 mice per concentration. In-vitro cytotoxicity test was done on Veto cells at concentrations （1.58～100 μg/mL） of MPE of Terminalia chebula. Results of in-vitro trypanocidal activity varied from immobilization, reduction and to the killing of the trypanosomes. At 250 μg/mL ofMPE ofTerminalia chebula dried fruits, there was significant trypanocidal activity at 4 h of incubation and trypanosomes were not detected in corresponding ELISA plate wells at 5 h of incubation, which was statistically equivalent to reference drug, diminazine aceturate （50 μL/mL） at 4 h of incubation. Results of in-vivo trypanocidal activity revealed that at concentrations （l 2.5～25 mg/kg body weight） of MPE of Terrninalia chebula, mice in these groups survived for 6 days. While at 50 and 100 to 200 mg/kg body weight, mice in these groups survived up to 7 and 8 days, respectively. In-vitro cytotoxicity test showed that all concentrations of MPE of Terminalia chenula and diminazine aceturate were cytotoxic to cells except at 1.56 μL/mL and 6.25 μL/mL. In conclusion, MPE of Terminalia chebula dried fruits possessed trypanocidal compounds. Further study （bioassay-guided purification） is required to know the full potential of Terrninalia chebula as future trypanocide candidate.

Study on Biocompatibility of Cross-linked Hyaluronic Acid Derivatives

Objective:The cross-linked production,which was prepared by HA and cross-linking agent STMP,EDC,GP through cross-linking reaction,might be used in drug delivery system(DDS).To ensure the security of clinical application,the excellent properties such as none cell toxicity,nonirritant,none general toxicity,none immunological rejection are necessary.Methods:In accordance with the request of GB/T 16886.1 on security evaluation of medical biomaterials,cell toxicity test,hemolysis test,intracutaneous stimulation test,acute toxicity test,and hypersensitive test were required.Results:Cell toxicity of HA-STMP,HA-EDC,HA-GP were all less than 1.All hypersensitive tests were eligible.But HA-EDC,HA-GP produced different degrees of slight thrill,slight toxicity,hemolysis rate,which were larger than the standard value.Conclusion:HA-STMP possesses favourable biocompatibility,which is a kind of ideal biomaterials and drug carriers.

Preparation of enzymatically cross-linked sulfated chitosan hydrogel and its potential application in thick tissue engineering

For the requirement of preliminary vascularization, the scaffolds for thick tissue engineering should have not only good cell affinity, but also anticoagulant ability. In this paper, enzymatically cross-linked hydrogel scaffolds based on sulfated chitosan （SCTS） were prepared. Firstly, sulfated chitosan-hydroxyphenylpionic acid （SCTS-HPA） conjugate was synthesized, and the structure of SCTS-HPA was identified by FITR and ~H NMR. And then the enzymatically cross-linked hydrogels were pre- pared in presence of horseradish peroxidase （HRP） and hydrogen peroxide （H202）. The gelation time, mechanical property, morphology and cytotoxicity to human umbilical vein endothelial cells （HUVECs） of the hydrogel were evaluated in vitro, the tissue compatibility of SCTS-HPA scaffold was studied in vivo. The results showed that the gelation time, mechanical property, morphology of the dehydrated hydrogel could be controlled by the the concentration of HRP and H202. The cytotoxicity test showed that the hydrogel extracts have no cytotoxicity to HUVECs. The in vivo assay indicated that SCTS-HPA scaffold have good tissue compatibility with no thrombus formation. All these results indicated that the SCTS-HPA scaffold could be used as a thick tissue engineering scaffold.

Metal complexes of a novel bis-β-diketone-type ligand and its copper(Ⅱ) complexes of two-photon biological imaging

A curcumin derivative ligand,1,7-bis(3-methoxyl-4-acetoxyl)phenyl-1,6-heptadiene-3,5-diketone (diacetylcurcumin,abbreviated as HL),and its Cu and Ni complexes have been synthesized and fully characterized by elemental analyses,IR,1 HNMR and molar conductivity.The resulting complexes exhibit two-photon excited fluorescence (TPEF) in DMF,and have been proven to be potentially useful for two-photon microscopy imaging in living cells.In addition,cytotoxicity tests showed that the low-micromolar concentrations of ML 2 did not cause significant reduction in cell viability over a period of at least 24 h and should be safe for further biological studies.

Acute toxicity study of Aspidopterys obcordata aqueous extract in Sprague-Dawley rats

OBJECTIVE: To examine the acute toxicity of an aqueous extract of Aspidopterys obcordata(A. obcordata) in Sprague Dawley rats.METHODS: The rats were orally administered a dose of 5000 mg/kg body weight and observed continuously for 6 h and then daily for 14 days. Control rats were administered distilled water. The effect of the extract on general behavior, body weight, and food and water intake were measured.After 14 days, the rats were sacrificed and their organs(liver, heart, spleen, lungs, kidney, adrenal glands, ovaries, and testes) were removed for macroscopic examination. The body and organ weights in addition to hematology(e.g., hemoglobin and white blood cell counts) and clinical blood biochemistry(e.g., albumin and bilirubin) were also examined.RESULTS: There were no deaths recorded, and the rats treated with A. obcordata showed no signs of toxicity. All measured parameters in rats treated with A. obcordata were unaffected when compared with those in control rats. The acute toxicity(LD_(50))was estimated to be > 5000 mg/kg body weight.CONCLUSION: Our results demonstrate the safety of an acute oral administration of an aqueous extract of A. obcordata in rats and indicate that future subacute and long-term toxicity testing of A. obcordata is warranted.