Novel PLGGE graft polymeric micelles for doxorubicin delivery

Novel poly{(lactic acid)-co-[(glycolic acid)-alt-(L-glutamic acid)]}-g-monomethyl poly(ethylene glycol) (PLGGE) micelles were prepared and used as carriers for anti-tumor drug delivery. Three PEGylated PLGG copolymers (PLGGE2000, PLGGE1100 and PLGGE500) were characterized by XRD, TG and DSC. The critical micelle concentrations (CMCs) of the amphiphilic copolymers were 1.04, 0.55 and 0.13 μg/mL, respectively. The TEM, AFM and DLS measurements revealed that the micelles were homogeneous spherical nanoparticles with the diameters ranged from 50 to 150 nm when THF was used as solvent in the preparation of the micelles. Interestingly, extended cylindrical micelles were obtained using CHCl 3 as solvent. The micelles could trap doxorubicin (DOX) in the core with the highest drug loading content up to 23.7%. The mean diameter of drug loaded micelles was much bigger than that of blank micelles. The in vitro drug release of the micelles was diffusion-controlled release within the first 36 h and initial burst release was not obvious. However, after 36 h, the release rate in pH 5.0 was faster than that in pH 7.4 due to the degradation. The PLGGE micelles were nontoxic to both NIH 3T3 fibroblasts and HepG2 cells. The in vitro cytotoxicity against HepG2 cells demonstrated that the drug loaded micelles exhibited high inhibition activity to cancer cells. CLSM observation of HepG2 cells showed that DOX released from the micelles could be delivered into cell cytoplasm and cell nuclei. PLGGE micelles are potential promising carriers for anti-tumor drug delivery.     

抗坏血酸在聚L-谷氨酸修饰玻碳电极上的电化学行为研究

采用电聚合的方法制备了聚L-谷氨酸修饰玻碳电极,该修饰电极对抗坏血酸(AA)具有良好的电催化作用,并对实验测定条件进行了优化.实验结果表明,在pH=4.0的邻苯二甲酸氢钾缓冲溶液中,扫描电位为-0.2～1.0 V范围内,抗坏血酸在聚L-谷氨酸修饰玻碳电极表面出现稳定的氧化峰.氧化峰的峰电流(Ipa)与抗坏血酸的浓度在2.0×10-5～2.0×10-3mol/L范围内有良好的线性关系,最低检测限可达2.0×10-6mol/L.该电极制备方便,有良好的稳定性和重现性.     

MA/AA无皂乳液聚合改性纳米SiO2

以α-甲基丙烯酸、丙烯酸为反应单体,对纳米SiO2进行无皂乳液聚合表面改性;采用正交试验法探讨了反应温度、反应时间、原材料配比反应条件对纳米SiO2粒子表面改性反应的影响,并对改性前后的纳米粒子进行了红外光谱(IR)分析和差热分析(DTA). 研究结果表明,较佳的改性聚合反应条件为反应温度80 ℃、反应时间3 h、原材料配比(单体与纳米SiO2质量比)为3:100,在此条件下进行改性反应改性效果明显.     

Protein adsorption on the poly（L-lactic acid） surface modified by chitosan and its derivatives

Surface modification of biomaterials has been adopted over the years to improve their biocompatibility. In this study, aiming to promote hydrophilicity and to introduce natural recognition sites onto poly（L-lactic acid） （PLLA） films, chitosan and its derivatives, carboxymethyl chitosan（CMC） and N-methylene phosphonic chitosan （NPC）, were used to modify the surface of PLLA films by an entrapment method. Radiolabeled （^125I） proteins were used to measure the amount of protein adsorbed to PLLA surfaces. Fibronectin （Fn） was used to study the protein adsorption on the modified PLLA surfaces, including isotherm adsorption and adsorption kinetics of single protein, competitive adsorption of binary proteins system and serum multi-proteins and the desorption behavior in serum solution. The results showed that in the isotherm adsorption, Fn had a larger adsorption capacity on the CS-modified surface at lower concentrations, but had a high adsorption capacity at CMC-modified surface at higher concentrations. In the study of absorption kinetics, Fn had a fastest adsorption equilibrium and a highest equilibrium adsorption capacity at the CS-modified surface, while it was opposite at the PCS-modified surface. When BSA and serum were added, it had the greatest effect on the adsorption of Fn on the PCS-modified surface. After 6 hours soaking in the desorpUon study, Fn had reached desorption equilibrium on all the modified surfaces, which had different effects on the desorption rate and the remaining percentage of Fn.     

酒石酸化学改性松针粉对Cr(VI)的吸附性能

本文选用松针粉(PNP)为原料,通过酒石酸化学改性制备出了一种新型生物吸附材料(TA-PNP).考察不同pH值、吸附反应时间和Cr(VI)溶液初始浓度等因素影响下,TA-PNP对Cr(VI)的吸附性能;并建立了动力学模型和等温线模型.实验结果表明:室温条件下,pH=2.0,吸附反应时间是60 min,Cr(VI)初始体积质量为750 mg/L时,TA-PNP对Cr(VI)吸附效果最佳.此外,TA-PNP吸附方式为化学吸附,颗粒内扩散模型表明总吸附反应速率为膜扩散和内扩散两者共同控制.TA-PNP对Cr(VI)的吸附行为符合Langmuir等温吸附模型,其最大吸附量为98.62 mg/g.     

药用肠溶性丙烯酸树脂的合成研究

以甲基丙烯酸与甲基丙烯酸甲酯为原料,过硫酸钾为引发剂,经溶液聚合制备出药用肠溶性丙烯酸树脂。考察了物料配比、反应温度、溶剂浓度、引发剂用量对反应的影响。     

聚对乙酰基偶氮胂膜修饰玻碳电极对抗坏血酸的催化氧化研究

用电化学聚合法研制了聚对乙酰基偶氮胂膜修饰玻碳电极 ,该电极对抗坏血酸 (AA)有良好的电催化氧化作用 ,AA在修饰电极上的氧化电位较空白玻碳电极负移约 4 50 m V。在选定的实验条件下 ,修饰电极以线扫伏安法测定 AA的线性范围为 5.0× 1 0 -5～ 1 .0× 1 0 -2 mol/L,检测下限为 1 .0× 1 0 -5mol/L。该电极具有较好的稳定性和重现性。     

聚1H-咪唑-4-甲酸-纳米氧化锌复合膜修饰电极的制备及其对抗坏血酸、多巴胺和尿酸的同时测定

采用电化学法在滴涂纳米氧化锌(ZnO)的玻碳电极(GCE)上聚合修饰1H-咪唑-4-甲酸(HIMC),制得聚1H-咪唑-4-甲酸-纳米ZnO(PHIMC-ZnO)复合膜修饰的GCE(PHIMC-ZnO/GCE),并用扫描电子显微镜(SEM)及电化学方法对修饰电极的形貌和电化学特性进行了表征.利用循环伏安法(CV)和差分脉冲伏安法(DPV)研究了抗坏血酸(AA)、多巴胺(DA)和尿酸(UA)在该修饰电极上的电化学行为.结果表明:在pH值为7.0的磷酸盐缓冲溶液(PBS)中,PHIMC-ZnO/GCE对AA,DA和UA均具有良好的电催化作用.在优化的实验条件下,AA,DA和UA的物质的量浓度线性范围分别为80～1 400,0.15～45.00和2～120μmol·L~(-1),相关系数分别为0.998 0,0.993 7和0.998 3,检出限(S/N=3)分别为0.50,0.03和0.09μmol·L~(-1).AA,DA和UA在不同扫速下的电化学行为表明:AA,DA和UA在PHIMC-ZnO/GCE上的电极过程受吸附过程控制,将PHIMC-ZnO/GCE应用于尿样和血清中AA,DA和UA的同时测定,结果令人满意.     

Methoxy poly（ethylene glycol）-b-poly（ethyl cyanoacrylate） copolymer nanoparticles as delivery vehicles for dexamethasone

Methoxy poly（ethylene oxide）-b-poly（ethyl cyanoacrylate） （mPEG-b-PECA）, amphiphilic block copolymer, was synthesized via oxyanion-initiated polymerization with a sodium alcoholate-terminated monomethoxy poly（ethylene glycol） as the macroinitiator. mPEG-b-PECA was characterized by GPC, 1H-NMR and FTIR. The results indicate that the structure of mPEG-b-PECA is well controlled with narrow molecular weight distribution. The dexamethasone （DXM）-loaded mPEG-b-PECA nanoparticles （NPs） were prepared by the nanoprecipitation technique and characterized by LPSA, 1H-NMR and TEM. The DXM-loaded mPEG-b-PECA NPs are of spherical shape with the size of less than 100 nm. The drug-loaded amount （DL） and encapsulation efficiency （EE） of DXM-loaded NPs were investigated by HPLC. The results show that DXM can be effectively incorporated into mPEG-b-PECA NPs, which provides a potential delivery system for DXM and other hydrophobic drugs.     

聚乳酸和乳酸-乙醇酸共聚物的溶液热力学

为了准确地预测溶液热力学数据,分别使用了36和38种溶剂对聚乳酸和乳酸-乙醇酸共聚物进行实验研究。采用正交优化计算方法确定了聚乳酸和乳酸-乙醇酸共聚物的三维溶度参数,分别为:δ_d=17. 969 (MPa)~(1/2),δ_p=6. 707 (MPa)~(1/2),δ_h=7. 324(MPa)~(1/2);δ_d=17. 083 (MPa)~(1/2),δ_p=6. 939 (MPa)~(1/2),δ_h=8. 650 (MPa)~(1/2)。单体中乳酸和乙醇酸浓度的升高会引起高分子聚合物溶度参数的增大。依据溶度参数,计算了聚乳酸和乳酸-乙醇酸共聚物与溶剂间的相互作用参数和相互作用半径。同时,计算了聚乳酸和乳酸-乙醇酸共聚物溶剂的体积修正系数,聚乳酸—溶剂体系和乳酸乙醇酸共聚物—溶剂体系的体积修正系数分别在0. 80～0. 90和0. 85～1. 10范围内。获得的相互作用参数、相互作用半径及体积校正系数完全符合Flory-Huggins高分子溶液理论。     

阳离子型高分子絮凝剂P(DMDAAC-AM)的分散聚合制备初探

采用分散聚合法,在乙醇-水体系中制备了二甲基二烯丙基氯化铵(dimethyl diallyl ammonium chloride, DMDAAC)和丙烯酰胺(acylamide, AM)的共聚物P(DMDAAC-AM)。研究了醇水质量比、单体质量分数、单体的物质的量比、引发剂用量、引发温度、EDTA等因素对聚合物的转化率和特性黏度的影响。使用红外光谱仪和透射电镜对产品的结构和形貌进行了表征。结果表明:以聚乙烯吡咯烷酮(PVP)为分散剂,用量为单体总质量的4％;在醇水质量比为1:1、单体质量分数为40％、DMDAAC与AM物质的量比为2:8、过硫酸钾为引发剂(其用量为体系总质量的0.04％)引发温度为40℃的条件下,得到特性黏度为94.77(cm3／g)、易分离提纯、溶解迅速的产品。     

一种改进的模糊C-均值(FCM)聚类算法

模糊C-均值(FCM)聚类算法受初始化影响较大,在迭代时容易陷入局部极小,鉴于遗传算法(GA)的并行全局搜索能力,文章将遗传算法引入进来对FCM聚类算法加以改进,并对所提出的新算法与经典算法的迭代步数和运行时间进行比较。实验结果表明:该算法与FCM聚类算法相比收敛速度更快,迭代步数更少。     

磷脂胆碱聚乳酸自组装胶束的结构与性能

用与天然磷脂结构和相对分子质量类似的磷脂月E{碱聚乳酸(Phosphorylcholine-containing poly(L-lactide),PLLA.pc)$sJ备自纽装胶束,采朋透射电镜和激光共聚焦显微镜进行观察.研究结果表明:胶束为外壳亲水内核疏水的实心球:表面张力法测得临界胶束质量浓度(Critical micelle concentration,CMC)~23 mg/L,显著低于天然磷脂胆碱质鼍浓度;当氯化钠质量分数低于0.9%时,CMC无明显变化,表明胶柬在生理盐水中较稳定:胶束被稀释时,动态光散射测得胶束粒径和粒径分布均逐渐变小,表明体系是动态体系;在37℃恒温条件下放置15 h,胶束数量、粒径和分布均变小,表明胶束可随时间降解;PLLA-PC胶束生物相容性好,可降解,可望成为新型的控释药物载体.     

碳纳米管/聚邻氨基苯甲酸复合物修饰电极的制备及其应用

邻氨基苯甲酸(o-ABA)在超声效应的诱导下可在多壁碳纳米管(MWCNTs)表面形成聚邻氨基苯甲酸(POABA)膜,其生成的碳纳米管与聚邻氨基苯甲酸的复合物具有良好的水溶性和电化学活性,可以通过电聚合的方法被修饰在石墨电极表面.该修饰电极对尿酸(UA)呈现出很好的分离、富集和电催化氧化作用.据此,建立了分析特性优良的尿酸测定的电化学分析新方法.结果表明,在最佳实验条件下,尿酸的氧化峰电流与尿酸的浓度在7.0×10-8～1.0×10-5mol/L内呈线性关系,检出限为3×10-8mol/L.该修饰电极可直接用于尿液中尿酸的测定.     

微机电系统(MEMS)在施药中的应用

探讨微型生物传感器和药液贮囊容器单元植入体内,用一无线集成系统能控制药物的释放.接收传感器接收并反馈信号,可同时进行治疗药剂注射及组织采样等作业.本文主要介绍了MEMS(NEMS)技术在施药系统中的应用,并且对其发展给予了展望.     

微机电系统（MEMS）在施药中的应用

探讨微型生物传感器和药液贮囊容器单元植入体内，用一无线集成系统能控制药物的释放。接收传感器接收并反馈信号，可同时进行治疗药剂注射及组织采样等作业。本文主要介绍了MEMS（NEMS）技术在施药系统中的应用，并且对其发展给予了展望。     

微机电系统(MEMS)在施药中的应用

探讨微型生物传感器和药液贮囊容器单元植入体内,用一无线集成系统能控制药物的释放。接收传感器接收并反馈信号,可同时进行治疗药剂注射及组织采样等作业。本文主要介绍了MEMS(NEMS)技术在施药系统中的应用,并且对其发展给予了展望。     

BSA-SDS-Ag聚合物水凝胶性质的研究(Ⅲ)

报道影响水凝胶性质的因素及生色过程。研究表明，BSA－SDS－Ag聚合物水凝胶的吸光度A和电导率δ均随体系pH.Ag(NH3)2^ 浓度，反应温度和时间而变化。A除随温度升高而急剧增加之外，其它因素无前一平台；但δ的变化确较复杂。显色过程表明随Ag(NH3)2^ 浓度增加而加深，亦随反应时间的增加而加深，说明该体系为化学键合的凝胶体系，微粒的粒径亦随之变大。     

12—钼磷杂多酸（PMo12）聚／N，N—二甲基苯胺修饰电极的制备及电化学研究

采用恒电位电解法在水溶液中成功地制备了12－钼磷杂多酸（PMo12)／聚N，N－二甲基苯胺（PDMA）薄膜修饰电极，并研究了其电化学性质。此膜在酸性溶液中具有良好的氧化还原性能，且制备方法简单、快速，为有机／无机功能膜在电催化中的和研究方面提供了新的方法。