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排序方式: 共有97条查询结果,搜索用时 16 毫秒
1.
目的 探讨聚乙烯亚胺修饰的荧光素钠(PEI-NHAc-FS)纳米颗粒(nanoparticles,NPs)在荧光素眼底血管造影术的应用和安全性。方法 选取90只健康棕色雄性挪威大鼠作为实验动物。将1 mL 荧光素钠(200 g·L-1)加入10 mol的1-乙基-(3-二甲基氨基丙基)碳酰二亚胺盐酸盐(EDC)混合物中搅拌30 min,再加入10 mol的N-羟基琥珀酰亚胺搅拌3 h。然后将该溶液加入到5 mL聚乙烯亚胺(polyethyleneimine,PEI)(76 g·L-1)中,剧烈搅拌3 d获得PEI-NH2-FS。将2 mL三乙胺加入到PEI-NH2-FS原液中,30 min后再将1 mL的乙酸酐加入混合物中搅拌24 h,合成PEI-NHAc-FS。使用核磁共振波谱仪和紫外可见光吸收光谱观察PEI-NHAc-FS的结构,并对合成的NPs结构进行表征;CCK-8检测其细胞毒性。选取30只大鼠,根据荧光素钠和PEI-NHAc-FS NPs的浓度(5 g·L-1、10 g·L-1、50 g·L-1)将大鼠分为6组,每组5只,分别于注射前及注射后5 min、20 min、30 min和60 min进行眼底摄像,采集大鼠眼底血管荧光素图像。用激光诱导大鼠脉络膜新生血管模型后,取10只大鼠,随机分为10 g·L-1荧光素钠组和PEI-NHAc-FS NPs组,每组5只,分别于注射前及注射后5 min、20 min、30 min和60 min通过眼底血管造影成像观察病灶处渗漏。另取40只大鼠,随机分为10 g·L-1荧光素钠组和PEI-NHAc-FS NPs组,每组20只,于注射后10 min、20 min、30 min和60 min进行荧光冰冻切片。将10只大鼠随机分为对照组(注射生理盐水)和PEI-NHAc-FS NPs组,每组5只,行组织切片HE染色和视网膜电图检测。采用HE染色和视网膜电图观察PEI-NHAc-FS NPs在体内的生物安全性。结果 通过核磁共振和紫外可见光吸收光谱观察到荧光素钠与PEI成功耦合。发射荧光光谱显示,游离荧光素钠和PEI-NHAc-FS NPs的最大发射波长分别出现在546 nm和544 nm处。CCK-8检测结果表明,不同浓度的荧光素钠和PEI-NHAc-FS NPs处理人脐静脉内皮细胞12 h、24 h后,细胞活性差异无统计学意义(P>0.05)。即使用10 μmol·L-1 PEI-NHAc-FS NPs处理24 h和未处理之间细胞存活率差异亦无统计学意义(P>0.05)。在5 g·L-1游离荧光素钠组和PEI-NHAc-FS NPs组中,均仅显影视网膜主要血管,不能用于荧光素眼底血管造影的诊断。而在10 g·L-1游离荧光素钠组和PEI-NHAc-FS NPs组可清晰地显示视网膜主要血管及微血管的结构,且在注射后30 min时血管荧光强度基本相同。PEI-NHAc-FS NPs组在60 min时荧光强度已基本消失,而游离荧光素钠组仍保持较强的荧光强度。10 g·L-1游离荧光素钠组和PEI-NHAc-FS NPs组荧光素眼底血管造影结果显示,经尾静脉注射造影剂后,视网膜血管内可见荧光成像;同时病灶部位可见荧光渗漏。游离荧光素钠组在视网膜组织中荧光较强,对视网膜组织有较强的吸附和渗透作用,而PEI-NHAc-FS NPs组在视网膜组织中荧光较弱,对视网膜组织吸附较弱。HE染色和视网膜电图对造影剂进行体内生物安全性分析结果显示,PEI-NHAc-FS NPs安全性较好。结论 PEI-NHAc-FS NPs能够安全、有效地用于荧光素眼底血管造影。  相似文献   
2.
Objective: The study was undertaken to investigate the effects of polyethyleneimine (PEI)-mediated adenovirus 5 early region 1A (E1A) on radiosensitivity of human hepatic carcinoma cell in vitro and to disclosure the underlying mechanism. Materials and Methods: Human hepatic carcinoma SMMC-7721 cell line was transfected with E1A gene using PEI vector. Untransfected cells (SMMC-7721 group), cells transfected with blank-vector (SMMC-7721-vect group), and cells transfected with E1A gene (SMMC-7721-E1A group) were treated with 6 MV X-ray irradiation at doses of 0, 1, 2, 4, 8 and Gy, respectively. Radiosensitivity was determined by MTT assay and quantified by calculating the cell survival rate. Cell-cycle distribution and apotosis rate were monitored by flow cytometry. Results: The survival rate of SMMC-7721-E1A was significantly lower than that of SMMC-7721 cell. Apoptosis rate of SMMC-7721-E1A group was significantly higher than that of SMMC-7721group (P<0.01).The ratio of S stage in cell cycle of SMMC-7721-E1A was significantly lower than that in SMMC-7721 cell. The ratio of G2/M stage in cell cycle of SMMC-7721-E1A was significantly higher than that in SMMC-7721 cell (P<0.01). Conclusion: PEI could transfect E1A gene into hepatic carcinoma cells PEI-mediated E1A could effectively enhance radiosensitivity of hepatic carcinoma cells which may be related to its effects on apoptosis promoting leading to S phase suppression and G2/M phase arrest.  相似文献   
3.
4.
《Immunobiology》2022,227(6):152283
The claudin 18.2(CLDN18.2) antigen is highly expressed in gastric mucosa epithelial cells and frequently expressed in malignant tumors. Positive clinical outcomes have popularized claudin 18.2 as a novel cellular and antibody therapeutic. Here, we designed a bispecific antibody-ZWB67 using the XFab® platform, aimed at redirecting CD3+ effector T cells to CLDN18.2+ target cells or tissues. Physicochemical characterization, binding properties, T cell stimulatory activity, and T cell-dependent cellular cytotoxicity of ZWB67 were evaluated in dosage intervals using antigens of CD3 and target cells expressing CLDN18.2 or CD3. Then, the anti-tumor activity was assessed in humanized CD3EDG mice bearing MC-38-hCLDN18.2 tumors. Our data demonstrate that ZWB67 specifically binds to the human CD3e antigen (KD = 1.04E?08 M) and binds more strongly to CLDN18.2+ cells than to CD3+ cells (4.3- to 9.2-fold difference). ZWB67 showed good activity in the luciferase reporter system and exhibited dose-dependent activation, cytotoxicity of T cells, and cytokine release when co-cultured with CLDN18.2+ cells and CD3+ T cells. ZWB67 also exhibited high in vivo efficacy in the MC-38-hCLDN18.2 xenograft mouse model. In conclusion, the novel anti-CLDN18.2 × anti-CD3 bispecific antibody exhibited low affinity for anti-CD3, highly specific binding, potent cytotoxicity, and anti-tumor activity. These data provide a basis for future preclinical and clinical development of this therapeutic strategy.  相似文献   
5.
目的:制备新型分子影像探针标记间充质干细胞,以实现细胞荧光成像。方法应用1‐碘十二烷修饰聚乙烯亚胺,构建两亲性大分子。利用大分子自组装性能,包裹疏水性核壳结构CdSe/CdS量子点构建纳米探针。结果该探针在630 nm处呈现出较强的荧光信号,能够促使间充质干细胞高效内吞。体内成像结果显示,与空白对照细胞相比,被标记细胞呈现出显著的光学信号,空白组信号值为1.47 e8[p/s/cm2/sr]/[μW/cm2],实验组信号值为2.78 e8[p/s/cm2/sr]/[μW/cm2]。结论该纳米探针具有良好光学成像性能,可实现细胞标记。  相似文献   
6.
目的 制备聚乙烯亚胺修饰纳米金基因载体并研究其理化性质的表征参数和体外转染效率.方法 通过化学还原法制备聚乙烯亚胺修饰的纳米金基因载体,用绿色荧光蛋白质粒(pAcGFP-N1)做报告基因,纳米基因载体可通过静电吸附的方式结合质粒DNA.用紫外分光光度计检测其吸收光谱,用透射电镜观察其形态特征,激光粒度分析仪测定其粒度分布、表面电位(Zeta电位),1%琼脂糖凝胶电泳检测该基因载体与质粒DNA的结合稳定性,CCK-8实验检测聚乙烯亚胺修饰纳米金基因载体及DNA-纳米金复合物对HEK293细胞的细胞毒性作用,通过荧光显微镜观察聚乙烯亚胺纳米基因载体介导pAcGFP-N1在体外培养的HEK293细胞中的表达,并分析其转染效率.结果 聚乙烯亚胺还原氯金酸可以得到带正电荷的纳米颗粒,呈单分散球形分布,其粒径为(12.3 ±3.3)nm.在pH =7.2时,Zeta电位为+(29.7±5.1)mV.1%琼脂糖凝胶电泳结果表明,当纳米金/质粒DNA≥0.5时,质粒DNA可完全结合到纳米金表面.体外转染实验表明,聚乙烯亚胺修饰纳米金基因载体能介导pAcGFP-N1转染HEK293细胞并在细胞中表达绿色荧光蛋白,其转染效率可达25%.结论 聚乙烯亚胺修饰纳米金是一种新型非病毒基因载体,具有转染效率高、对细胞毒性小等优势.  相似文献   
7.
Oral drug absorption is a process influenced by the physicochemical and biopharmaceutical properties of the drug and its inter-relationship with the gastrointestinal tract. Drug solubility, dissolution and permeability across intestinal barrier are the key parameters controlling absorption. This review provides an overview of the factors that affect drug absorption and the classification of a drug on the basis of solubility and permeability. The biopharmaceutical classification system (BCS) was introduced in early 90׳s and is a regulatory tool used to predict bioavailability problems associated with a new entity, thereby helping in the development of a drug product. Strategies to combat solubility and permeability issues are also discussed.  相似文献   
8.
In order to evaluate the in vivo effect of inhaled formulations, it is a gold standard to create a lung metastasis model by intravenously injecting cancer cells into an animal. Because the cancer grows from the blood vessel side, there is a possibility of underestimating the effect of an inhaled formulation administered to the lung epithelium side. In addition, the metastasis model has disadvantages in terms of preparation time and expense. The present study aimed to establish a new method to evaluate the effect of an inhaled small interfering RNA (siRNA) formulation that is more correct, more rapid, and less expensive. We investigated whether siRNA can suppress gene expression of plasmid DNA (pDNA) by serial pulmonary administration of siRNA and pDNA powders prepared by spray-freeze-drying. We revealed that formulations of dry siRNA powder significantly suppressed gene expression of pDNA powder compared with a control group with no siRNA. Naked siRNA inhalation powder with no vector showed the suppression of gene expression equivalent to that of an siRNA-polyethyleneimine complex without damaging tissues. These results show that the present method is suitable for evaluating the gene-silencing effect of inhaled siRNA powders.  相似文献   
9.
Abstract

Bacterial infection has become a serious clinical concern due to the emergence of drug-resistance and biofilm formation. Therefore, it is in great demand to develop efficient antimicrobial agents to treat bacterial infection without using antibiotics. Herein, we successfully prepared four quaternized ammonium PEI (QPEI: PEI1200-C2, PEI1200-C4, PEI1200-C6 and PEI1200-C8) using the commercial available PEI1200. Both PEI and four QPEI presented broad-spectrum antimicrobial activity against Gram-negative bacteria (E. coli, and P. aeruginosa) and Gram-positive bacteria (B. amyloliquefaciens and S. aureus), especially PEI1200-C6 showed the strongest antimicrobial activity with good biocompatibility at the MIC concentrations. Besides, PEI1200-C6 showed 4-16-fold better antibacterial effect than PEI1200, and fluorescent microscope imaging demonstrated that both of them could efficiently eradicate biofilms formed by four bacterial strains in vitro. As the accessible broad-spectrum antibacterial agents, PEI1200 and PEI1200-C6 are significant candidates to treat bacterial infections or eradicate biofilms on indwelling medical devices.  相似文献   
10.
Poly(ethylenimine) and its role in gene delivery   总被引:31,自引:0,他引:31  
Since the first published examination of poly(ethylenimine) (PEI) as a gene delivery vehicle, there has been a flurry of research aimed at this polycation and its role in gene therapy. Here we will briefly review PEI chemistry and the characterization of PEI/DNA complexes used for gene delivery. Additionally, we will note various PEI transfection considerations and examine findings involving other polycationic gene delivery vehicles used with cellular targeting ligands. The current state of our knowledge regarding the mechanism of PEI/DNA transfection will also be discussed. Finally, we will survey toxicity issues related to PEI transfection.  相似文献   
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