电纺丝技术制备组织工程食管仿生支架

背景：前期实验中曾发现纤维的取向可以引导平滑肌细胞的取向生长,因此,设想通过制备取向排列的电纺丝纤维支架,以引导食管平滑肌细胞的有序生长,从而有利于维持肌细胞的形貌及生物功能。 目的：以可降解聚己内酯、明胶、丝素蛋白为基材,采用自制的电纺丝系统制备无规和有序的纳米级多孔纤维。 方法：将聚己内酯与丝素蛋白以4∶1质量比混合,通过调整溶液浓度、电压、喷射速度等参数,采用自制的电纺丝系统制备聚己内酯/丝素蛋白电纺丝纤维。将聚己内酯与明胶分别以2∶1、1∶1、1∶2质量比混合,在金属平板接收器下,通过调整溶液浓度、电压、喷射速度等参数,采用自制的电纺丝系统制备聚己内酯/明胶无规电纺丝纤维;同时改用滚轴接收装置,通过调整滚轴转数、电压、喷射速度等参数,制备聚己内酯/明胶有序电纺丝纤维。 结果与结论：在溶液质量浓度为0.08 g/mL、纺丝液流速1.6 mL/h和电压22.5 kV的条件下,制得了均匀、无串珠、纤维直径为(535.9±126.7) nm的聚己内酯/丝素蛋白多孔纳米纤维膜。在溶液质量浓度为0.10 g/mL、纺丝液流速0.8 mL/h和电压22.5 kV的条件下,制得了无明显串珠、纤维直径为(257.9±117.8) nm的聚己内酯/明胶多孔纳米纤维膜;并且在1∶2质量比时更易成纤维,纤维尺寸更均匀。在滚轴转速3 000 r/min。溶液流速0.8 mL/h。电压15 kV的条件下,制得的聚己内酯/明胶有序电纺丝纤维排序更理想,纤维也更均匀。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

聚乙二醇-b-聚己内酯/聚己内酯单分散电喷微球的制备与亲水性研究

用静电喷雾法制备单分散性良好、亲水性的聚乙二醇-b-聚己内酯/聚己内酯(PEG-b-PCL/PCL)电喷微球。将聚乙二醇-b-聚己内酯(PEG-b-PCL)、聚己内酯(PCL)与氯仿混合磁力搅拌3 h后,采用静电喷雾的方法,以双亲(PEG-b-PCL)含量、流速、电压为变量,研究微球形态大小、粒径分布的变化,并研究微球亲水性随双亲含量的变化程度及微球在水中的分散性。双亲含10%～20%、流速1 mL/h、电压10 kV时能得到成球性佳、粒径5～6 μm的单分散性良好的微球,粒径的变异系数为15%～21%;双亲含量增至30%,微球之间由较多的纤维连接;双亲含量由0增至20%时,接触角由126.2°±4.8° 降至29.9°±4.9°,差异具有统计学意义(P<0.05),通过改变双亲含量能有效改善微球的亲水性,同时,加入10%～20%双亲的微球在水中分散性佳,能形成均匀的混悬液。PEG-b-PCL/ PCL能得到单分散、亲水性佳的微球,为进一步制备载药微球提供条件。     

聚多巴胺修饰聚己内酯电纺膜载铜涂层的制备及抗菌和细胞性能评价

背景:在口腔领域,引导骨组织再生膜被广泛用于口腔种植、牙周、颌面外科领域,用于快速有效的实现组织再生,但如何防止植入物周围感染一直是亟待解决的难题。目的:制备聚己内酯静电纺丝纤维,并通过聚多巴胺对其进行表面改性并黏附铜离子,以制备具有抗菌成骨双重功效的引导骨组织再生膜。方法:分别制备聚己内酯电纺膜、聚多巴胺修饰聚己内酯电纺膜与聚多巴胺修饰载铜(铜离子浓度分别为0.01,0.1,1 mol/L)聚己内酯电纺膜。将MC3T3-E1细胞分别接种于上述电纺膜上,通过CCK-8实验检测细胞增殖;将变形链球菌分别与上述电纺膜共培养,检测各组抑菌率。通过CCK-8与抑菌率实验结果确定合适的载铜浓度,用于后续实验。检测聚多巴胺修饰载铜聚己内酯电纺膜的体外缓释性能。将MC3T3-E1细胞分别接种于聚己内酯电纺膜、聚多巴胺修饰聚己内酯电纺膜与聚多巴胺修饰载铜聚己内酯电纺膜上,通过活/死细胞染色分析细胞活性,碱性磷酸酶染色评价细胞早期成骨分化;将变形链球菌与上述3种电纺膜共培养,活/死细菌染色评价电纺膜抗菌活性。结果与结论:(1)CCK-8实验结果显示,载铜(0.01,0.1 mol/L)电纺膜可促进MC3...     

纳米羟基磷灰石/聚己内酯复合大鼠骨髓间充质干细胞的生物相容性

背景：纳米羟基磷灰石/聚己内酯是一种具有优良生物相容性和生物活性的典型生物复合材料。 目的：分析纳米羟基磷灰石/聚己内酯电纺薄膜作为组织工程骨支架的可行性。 方法：采用静电纺丝技术制备纳米羟基磷灰石/聚己内酯电纺薄膜,将其与第3代SD大鼠骨髓间充质干细胞复合培养,在地塞米松、β-磷酸甘油钠、维生素C成骨诱导剂诱导下,诱导骨髓间充质干细胞向成骨细胞转化。 结果与结论：纳米羟基磷灰石/聚己内酯支架具有合适的微孔结构,且孔道相互贯通。①倒置显微镜观察：复合培养 7 d后细胞大部分为梭形,细胞开始分裂;14 d后,细胞生长比较旺盛,数量明显增多,细胞分泌基质并黏附于支架上。②扫描电镜观察：复合培养7 d后大量细胞位于支架孔隙内生长,增殖良好,细胞大多呈梭形,双极突起,形态较佳,呈立体状生长,并分泌基质,有纤维连接蛋白生成。表明纳米羟基磷灰石/聚己内酯支架具有良好的生物相容性,是骨组织工程的良好载体。     

新型两亲性糖聚肽肝癌靶向诊疗一体化纳米粒子的制备及体内外实验研究

通过氨基酸环内酸酐进行开环聚合及Click反应,制备得到新型两亲性糖聚肽——含半乳糖结构单元的聚(N^ε-苄氧羰基-L-赖氨酸)/聚(L-谷氨酸酯)嵌段聚合物,通过红外光谱、核磁共振氢谱对产物结构进行表征;采用透析法制备糖聚肽纳米粒子,对其临界胶束浓度、粒径分布、表面形貌、生物活性、细胞毒性等进行考察。随后,以糖聚肽为载体包载近红外荧光染料IR780制备诊疗一体化纳米粒子,并对其在肝癌HepG2细胞的靶向摄取、光热疗效及活体成像效果方面进行评价。结果显示:该实验成功制备出含半乳糖结构单元的聚(N^ε-苄氧羰基-L-赖氨酸)/聚(L-谷氨酸酯)嵌段聚合物;这种糖聚肽在水溶液中的浓度达到0.015 μg/mL时,便可以通过自组装形成粒径大约85 nm的球形粒子。细胞毒性实验(MTT)表明,该纳米粒子具有较好的生物安全性,当其浓度达到500 μg/mL时,HepG2与HUVEC细胞仍保持90%以上的生存率。流式细胞术实验结果表明,以糖聚肽为载体,可高效地将IR780传送到HepG2细胞内,具有肝癌靶向能力;体外光热治疗实验结果证实,在808 nm波长激光照射下,对靶向吞噬诊疗一体纳米粒子的HepG2肝癌细胞具有杀伤作用,而且光热治疗效果与IR780的浓度成正相关,当IR780浓度为10.0 μM时,其治疗效果优于5.0 μM时的治疗效果。小动物活体成像实验表明,该诊疗一体化纳米粒子能特异性地聚集在肿瘤部位,经尾静脉注射24 h后仍具有明显的荧光特性。综上可见,该实验合成新型两亲性糖聚肽肝癌靶向诊疗一体化纳米粒子,在肝癌的靶向诊断与治疗中具有广阔的应用前景。     

仿生可降解组织工程纤维环支架的制备与评估

文题释义： 纤维环：是保持椎间盘强度与脊柱稳定性层面的重要组成部分,纤维环的胶原纤维在椎间盘内呈同心圆排列,每层纤维环间呈60°夹角斜行排列,这类特殊的交错网状架构,令纤维环拥有较强的抗拉性能与压缩性,能够预防髓核往外突出,对保持椎间盘的稳定起着重要的作用。 背景：构建既具有仿生结构又具备合适可降解性和良好生物相容性的组织工程纤维环支架仍是难点。 目的：以聚己内酯和聚二恶烷酮为原材料制备仿生可降解支架并评估其作为组织工程纤维环支架的可行性。 方法：通过熔融纺丝技术制备5组不同比例支架(聚己内酯组、聚己内酯/聚二恶烷酮分别为70/30、50/50、30/70组、聚二恶烷酮组)。扫描电子显微镜观察其结构、纤维直径、孔径;测量支架的力学性能和接触角;通过体外模拟和皮下埋植观察支架体外、体内降解情况;检测降解组织周围炎症因子白细胞介素1β和肿瘤坏死因子α的表达情况。接种人脐带间充质干细胞培养7 d,通过CCK-8和死活细胞检测细胞增殖和存活情况。实验于2016-03-02经天津市天津医院医学伦理委员会批准。 结果与结论：①扫描电子显微镜观察显示各组支架纤维粗细均匀,纤维成60°角;②力学性能分析显示单纯聚二恶烷酮支架的拉伸和压缩模量最低,不符合纤维环力学要求;聚己内酯组的力学性能最佳,聚己内酯/聚二恶烷酮为70/30和50/50的支架力学性能适中;③亲水性检测结果表明聚二恶烷酮含量越多,支架亲水性越好;④支架降解情况分析显示,对于组织工程纤维环再生修复来说,单纯聚二恶烷酮和聚己内酯/聚二恶烷酮为30/70支架降解过快,聚己内酯组的降解过慢,聚己内酯/聚二恶烷酮为70/30和50/50的支架降解速率较合适;⑤降解组织周围炎症反应分析显示支架中聚己内酯比例越高炎症反应越严重;⑥CCK-8和死活细胞结果显示人脐带间充质干细胞在聚己内酯/聚二恶烷酮三组混合支架具有良好的增殖活性并且存活率高;⑦结果表明,采用熔融纺丝技术制备的聚己内酯/聚二恶烷酮为70/30和50/50两组支架能够模拟天然纤维环结构,同时具备合适可降解性、优越的力学性能和良好生物相容性,适合用于组织工程纤维环支架的构建。 ORCID: 0000-0001-9088-4222(张维昊) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

紫杉醇纳米粒子的制备及其应用**◆

背景：紫杉醇临床用剂型紫素易引起过敏反应,因此研制新的紫杉醇新剂型就显得十分有意义。 目的：研制紫杉醇新剂型,观察其在动物模型上治疗肿瘤的效果。 方法：合成具有自主知识产权的生物可降解材料医用聚己内酯。采用溶剂替代法制备载紫杉醇纳米粒子,对其粒径、形态、紫杉醇含量、体外释放等进行测定。选用TA2系实验小鼠,建立乳腺癌动物模型,随机分为5组,分别局部注射生理盐水、紫素、低剂量、中剂量及高剂量紫杉醇纳米粒子进行治疗。 结果与结论：实验制备的紫杉醇纳米粒子平均粒径约为153.54 nm,包埋率为87.25%,紫杉醇含量19.06%。体外可恒定释放30 d以上。2周药物治疗显示,各治疗组均不同程度上抑制了肿瘤的生长,其中紫杉醇纳米粒子中、高剂量组的抑瘤率明显高于紫素治疗组(P < 0.01)。提示紫杉醇纳米粒子可缓释药物,中剂量组和高剂量组对小鼠乳腺癌的抑瘤率高于紫素组。关键词：紫杉醇;医用聚己内酯;纳米粒子;乳腺癌;缓释药物 缩略语注释：HPLC：high performance liquid chromatography,高效液相色谱 doi:10.3969/j.issn.1673-8225.2012.16.005     

构建淫羊藿苷/聚己内酯纳米纤维膜及体外促成骨能力

背景:在骨组织工程中,静电纺丝的应用使得促成骨生长因子能够更长久的发挥作用。研究表明,淫羊藿苷可促进MC3T3-E1细胞的增殖。目的:构建载淫羊藿苷/聚己内酯纳米纤维膜,评估其生物相容性及体外促成骨能力。方法:采用同轴静电纺丝技术制备淫羊藿苷/聚己内酯纳米纤维膜,表征其微观形貌及体外药物释放。体外培养MC3T3-E1细胞,分4组处理:空白组常规培养细胞,纳米纤维膜组加入聚己内酯纳米纤维膜,药物组加入含淫羊藿苷的培养基,实验组加入淫羊藿苷/聚己内酯纳米纤维膜,检测各组细胞骨架形态、增殖、碱性磷酸酶活性及骨钙素m RNA表达。结果与结论:(1)扫描电镜显示,淫羊藿苷/聚己内酯纳米纤维膜具有三维立体的网状交织的结构,相互交错,空隙大小均一,孔径100-200μm,纤维平均分布范围为300-600 nm;(2)观察淫羊藿苷/聚己内酯纳米纤维膜1个月内的药物释放累积量,开始1-5 d药物有突释现象,释药量达45%左右,后期药物呈缓慢持续释放,到30 d时药物释放量达80%以上;(3)培养24 h后激光共聚焦显微镜下可见,细胞黏附于纳米纤维膜生长,细胞肌动蛋白走行及细胞内部结构清晰;(4)CCK-...     

紫杉醇纳米粒子制备及血管内局部灌注后的组织分布

目的 制备紫杉醇纳米粒子,并考察其在实验兔体内经DispatchTM球囊灌注后组织分布情况.方法 以生物可降解材料聚乳酸聚乙醇酸共聚物(PLGA)为原料,采用超声乳化-溶剂挥发法制备载紫杉醇纳米粒子.对纳米粒子的粒径、形态、药物含量和体内外释放进行测定.通过新西兰兔腹主动脉局部给药模型考察紫杉醇纳米粒子球囊灌注后组织分布情况.结果 制备的紫杉醇纳米粒子的平均粒径约为246 nm,包封率为93.25％,紫杉醇含量19.06％.体外可维持恒定释放30d以上.新西兰兔体内经腹主动脉实现DispatchTM球囊灌注,观察药物可在靶部位体内贮留长达21d.结论 紫杉醇PLGA纳米粒子作为一种局部药物传递系统,经球囊灌注在动物模型体内提高局部药物浓度,延长药物作用时间,可实现缓释靶向治疗.     

3D打印成型纳米羟基磷灰石/壳聚糖/聚己内酯三元复合支架材料的构建及表征

文题释义： 组织工程骨：将体外培养的功能相关的种子细胞种植于天然的或人工合成的支架材料内,加入生长因子体外培养一段时间,将他们移植到体内,促进组织修复和骨再生的人工骨。组织工程骨形成的3要素为：支架材料、成骨细胞、生长因子。 生物陶瓷：生物表面活性陶瓷通常含有羟基,还可做成多孔性,生物组织可长入并同其表面发生牢固的键合;生物吸收性陶瓷的特点是能部分吸收或者全部吸收,在生物体内能诱发新生骨的生长。生物活性陶瓷具有骨传导性,它作为一个支架,成骨在其表面进行;还可作为多种物质的外壳或填充骨缺损。生物陶瓷有羟基磷灰石陶瓷、磷酸三钙陶瓷等。  背景：目前常用的骨缺损修复支架材料种类较多,但单一类型材料难以满足骨组织工程支架材料的要求,通过合适的方法将几种单一材料组合形成复合型材料,综合考虑各种材料优缺点,是近年来学者们的研究重点。 目的：构建纳米羟基磷灰石/壳聚糖/聚己内酯三元复合支架材料,并作表征分析研究。 方法：采用3D打印成型技术制备纳米羟基磷灰石/壳聚糖/聚己内酯多孔三元复合支架材料,从X射线衍射分析、吸水率、抗压强度、体外降解性能、孔径分析、扫描电镜分析等多个维度对支架材料进行表征研究。 结果与结论：①X射线衍射分析显示,纳米羟基磷灰石/壳聚糖/聚己内酯多孔三元复合支架的晶型峰图与羟基磷灰石粉末衍射标准卡片类似,表明该三元复合支架是通过物理作用相互结合的,不影响羟基磷灰石的生物学功能;②三元复合支架的吸水率为18.28%,亲水性好,支架可承受的最大压力为1 415 N,其体外降解速率与成骨速率相当;③显微镜下可见三元复合支架的内孔为方形,孔径250 µm,孔径大小均匀、分布有致;④扫描电镜下三元复合支架可见,壳聚糖和聚己内酯组成的纤维排列整齐有序,成网格状, 羟基磷灰石呈颗粒状在纤维表面均匀分布,三元复合材料呈现均匀、疏松的微孔结构;⑤结果表明,通过3D打印成型技术可成功制备纳米羟基磷灰石/壳聚糖/聚己内酯三元复合支架材料,其具有适度的抗压强度、一定的孔隙率、适宜的降解速度和吸水率,能为修复骨缺损的奠定基础。 ORCID: 0000-0002-6321-9160(余和东) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程       

Amphiphilic and biodegradable methoxy polyethylene glycol-block-(polycaprolactone-graft-poly(2-(dimethylamino)ethyl methacrylate)) as an effective gene carrier

A group of amphiphilic cationic polymers, methoxy polyethylene glycol-block-(polycaprolactone-graft-poly(2-(dimethylamino)ethyl methacrylate)) (PECD), were synthesized by combining ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) methods to form nanoparticles (NPs). The structures of these amphiphilic cationic polymers were characterized by (1)H NMR measurement. The PECD NPs have hydrophobic cores covered with hydrophilic PEG and cationic PDMAEMA chains. These self-assembly nanoparticles were characterized by dynamic light scattering (DLS) technique. PECD NPs can effectively condense DNA to form compact complexes of the size 65-160 nm suitable for gene delivery. The in vitro gene transfection studies of HeLa and HepG2 cells show that PECD NPs have better transfection efficiency compared to polyethylenimine (PEI) and Lipofectamine 2000 at low dose (N/P = 5). The cytotoxicity result shows that PECD NPs/DNA complexes at the optimal N/P ratio for transfection have comparable toxicity with PEI and Lipofectamine. These results indicate that PECD NPs have a great potential to be used as efficient polymeric carriers for gene transfection.     

Amphiphilic block copolymer NPs obtained by coupling ricinoleic acid/sebacic acids and mPEG: Synthesis,characterization, and controlled release of paclitaxel

Abstract

Currently, nanoparticles (NPs) made of amphiphilic block copolymer are still an essential part of drug delivery system. Here, we report a novel amphiphilic block copolymer and paclitaxel (PTX)-loaded copolymer NPs for the controlled delivery of PTX. The block copolymer was synthesized via melt polycondensation method of methoxy poly(ethylene glycol) (mPEG), sebacic acid (SA) and ricinoleic acid (RA). A series of characterization approaches such as Fourier Transform Infrared Spectroscopy (FTIR), ¹Hydrogen-Nuclear Magnetic Resonance (¹H-NMR), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD) and Gel Permeation Chromatography (GPC) applied have shown that the amphiphilic block copolymer was prepared as designed. NPs prepared by nanoprecipitation method consist of mPEG segments as the hydrophilic shell and RA-SA segments as the hydrophobic core, hydrophobic PTX was encapsulated as model drug. Subsequently, Transmission Electron Microscopy (TEM) analysis indicated that the spherical NPs have effective mean diameters ranging from 100 to 400?nm. Dynamic Light Scattering (DLS) analysis also revealed the controllable NPs diameter by modulating the mass ratio of RA to SA and drug loading amount (DLA). Besides, biphasic profile with zero order drug release was observed in general in vitro release behaviors of PTX from NPs. Further investigation confirmed that the release behaviors depend on the crystallinity of hydrophobic RA-SA segments. Results above suggest that NPs with amphiphlic block copolymer mPEG-b-P(RA-SA)-b-mPEG have a remarkable potential as a carrier for hydrophobic drug delivery in cancer therapy.     

A mPEG-PLGA-b-PLL copolymer carrier for adriamycin and siRNA delivery

A amphiphilic block copolymer composed of conventional monomethoxy (polyethylene glycol)-poly (d,l-lactide-co-glycolide)-poly (l-lysine) (mPEG-PLGA-b-PLL) was synthesized. The chemical structure of this copolymer and its precursors was confirmed by Fourier Transform Infrared Spectroscopy (FTIR), (1)H Nuclear Magnetic Resonance ((1)H NMR) and Gel Permeation Chromatography (GPC). The copolymer was used to prepare nanoparticles (NPs) that were then loaded with either the anti-cancer drug adriamycin or small interfering RNA-negative (siRNA) using a double emulsion method. MTT assays used to study the in vitro cytotoxicity of mPEG-PLGA-b-PLL NPs showed that these particles were not toxic in huh-7 hepatic carcinoma cells. Confocal laser scanning microscopy (CLSM) and flow cytometer analysis results demonstrated efficient mPEG-PLGA-b-PLL NPs-mediated delivery of both adriamycin and siRNA into the cells. In vivo the targeting delivery of adriamycin or siRNA mediated by mPEG-PLGA-b-PLL NPs in the huh-7 hepatic carcinoma-bearing mice was evaluated using a fluorescence imaging system. The targeting delivery results and froze section analysis confirmed that drug or siRNA is deliver to tumor more efficiently by mPEG-PLGA-b-PLL NPs than free drug or Lipofectamine?2000. The high efficiency delivery of mPEG-PLGA-b-PLL NPs mainly due to the enhancement of cellular uptake. These results imply that mPEG-PLGA-b-PLL NPs have a great potential to be used as an effective carriers for adriamycin or siRNA.     

Copolymer nanoparticles composed of sulfobetaine and poly(ε-caprolactone) as novel anticancer drug carriers

Novel ABA type amphiphilic copolymers (PCL-APS-PCL) consisting of polycaprolactone (PCL) (A) as hydrophobic block and N,N'-bis (2-hydroxyethyl) methylamine ammonium propane sulfonate (APS) (B) as hydrophilic segment, self-assembled into nanoparticles (NPs) with solvent evaporation method. The sizes and size distributions of NPs were characterized by dynamic light scattering. The morphology of NPs was observed by scanning electron microscopy (SEM). The critical micelle concentration (CMC) was determined by fluorescent probe. The drug loading content (DLC) and the drug release amount were characterized by UV-visible spectrophotometer. The cytotoxicity of the NPs was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazoliumbromide (MTT) assay. It was found that the NPs were spherical in shape with sizes around 100 nm. The CMCs of the copolymers were quite low (×10(-4) mg/mL). The DLC decreased with lengthening of hydrophobic PCL block. In vitro drug release experiment demonstrated that the release rate of paclitaxel sped with the decrease of PCL length. MTT results showed that NPs were nontoxic to osteoblast and human epithelial carcinoma (hela) cells. After drug loading, NPs could restrain the growth of hela or even kill hela cells. Therefore, these preliminary studies suggest that the novel PCL-APS-PCL NPs have a great potential application as anticancer drug-delivery carriers.     

Structural contributions of blocked or grafted poly(2-dimethylaminoethyl methacrylate) on PEGylated polycaprolactone nanoparticles in siRNA delivery

The multiformity in polymer structure and conformation design provides a great potential in improving the gene silencing efficiency of siRNA by polymer vectors. In order to provide information on the polymer design for siRNA delivery, the structural contributions of blocked or grafted poly(2-dimethylaminoethyl methacrylate) on PEGylated polycaprolactone nanoparticles (NPs) in siRNA delivery were studied. Herein, two kinds of self-assembly nanoparticles (NPs) formed by amphiphilic cationic polymers, methoxy poly(ethylene glycol)-block-polycaprolactone-block-poly(2-dimethylaminoethyl methacrylate) (mPEG-PCL-b-PDMAEMA, PECbD) and methoxy poly(ethylene glycol)-block-(polycaprolactone-graft-poly(2-dimethylaminoethyl methacrylate)) (mPEG-PCL-g-PDMAEMA, PECgD), were used to deliver siRNA for in vitro and in vivo studies. The physiochemical properties including size and zeta potential of PECbD NPs/siRNA and PECgD NPs/siRNA complexes were characterized. In vitro cytotoxicity, cellular uptake and siRNA knockdown efficiency were evaluated in HeLa-Luc cells. The endosome escape and intracellular distribution of PECbD NPs/siRNA and PECgD NPs/siRNA in HeLa-Luc cells were also observed. In vivo polymer mediated siRNA delivery and the complexes distribution in isolated organs were studied using mice and tumor-bearing mice. At the same total degree of polymerization (DP) of DMAEMA, PECgD NPs/siRNA complexes possessed higher zeta potentials than PECbD NPs/siRNA complexes (at the same N/P ratio), which may be the reason that PECgD NPs/siRNA complexes can deliver more siRNA into the cytoplasm and lead to higher in vitro luciferase and lamin A/C silencing efficiency than PECbD NPs/siRNA complexes. The in vivo imaging measurement and histochemical analysis also confirmed that siRNA could be delivered to lungs, livers, pancreas and HeLa-Luc tumors more efficiently by PECgD NPs than PECbD NPs. Meanwhile, the PDMAEMA chains of PECgD could be shortened which provides benefits for clearing. Therefore, PECgD NPs have great potential to be used as efficient non-viral carriers for in vivo siRNA delivery.     

In vitro evaluation of antisense oligonucleotide functionalized core-shell nanoparticles loaded with α-tocopherol succinate

Antisense oligonucleotide (ASO)-conjugated-α-tocopherol succinate (TCS)-loaded-poly(lactic acid)-g-poly(ethylene glycol) nanoparticles (ASO-TCS-PLA-PEG NPs), with the ratio of polymer/TCS of 10:2.5, 10:5, 10:7 (w/w) were prepared for targeting cancer therapy. The amphiphilic PLA, amino terminated PEG graft copolymers were synthesized by ring opening polymerization reaction. Nanoparticles were produced by using double emulsion (w/o/w) solvent evaporation method. ASO-TCS-PLA-PEG NPs demonstrated satisfactory encapsulation and loading efficiency and size distribution. The short-term stability studies were carried out at 4 and 25 °C for 30 days to assess their mean particle size, polydispersity index and zeta potential. The cellular uptake and extended cytoplasmic retention of the NPs in A549 human lung carcinoma and L929 mouse fibroblast cells were examined by fluorescence and confocal microscopy. In human lung cancer cells, ASO-TCS-PLA-PEG NPs exhibited better cellular internalization, cytotoxicity and apoptotic and necrotic effects compared to healthy cell line, L929. These findings showed that ASO-modified nanoparticles could serve as a promising nanocarrier for targeted tumor cells.     

Anti-tumor activity of paclitaxel through dual-targeting carrier of cyclic RGD and transferrin conjugated hyperbranched copolymer nanoparticles

Targeted delivery strategies are becoming increasingly important. Herein, a novel hyperbranched amphiphilic poly[(amine-ester)-co-(d,l-lactide)]/1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine copolymer (HPAE-co-PLA/DPPE) with RGD peptide (cRGDfK) and transferrin (Tf) on the periphery was synthesized and used to prepare paclitaxel-loaded nanoparticles (NPs) for dual-targeting chemotherapy. These NPs show satisfactory size distribution, high encapsulated efficiency and a pH-dependent release profile. The intrinsic fluorescence of the hyperbranched copolymer renders the detection and tracking of NPs in vitro and in vivo conveniently. In vitro cytotoxicity studies proved that the presence of cRGDfK enhanced the cytotoxic efficiency by 10 folds in α_νβ₃ integrin over-expressed human umbilical vein endothelial cells, while Tf improved cytotoxicity by 2 folds in Tf receptor over-expressed human cervical carcinoma cells. The drug-loaded NPs can be efficiently transported into the vascular endothelial cells and the target tumor cells. These results indicate that the cRGDfK and Tf decorated HPAE-co-PLA/DPPE could deliver chemotherapies specifically inside the cell via receptor-mediated endocytosis with greater efficacy. Therefore, such a fluorescent nanocarrier prepared from non-cytotoxic and biodegradable polymers is promising for drug delivery in tumor therapy.     

Tat-聚乙二醇修饰明胶-硅氧烷纳米粒跨血脑屏障研究

明胶-硅氧烷杂化材料具有低毒、表面易修饰、易重复合成等优点,并可介导外源基因在细胞内进行高效率转染,是一种潜在的高效基因载体材料。本文通过两步溶胶-凝胶反应合成明胶-硅氧烷纳米粒(GS NPs),经Tat多肽(KYGRRRQRRKKRGC)、聚乙二醇(PEG)表面修饰构成Tat-PEG-GS NPs。应用透射电镜(TEM)、粒径仪和活体成像系统对其粒径、形貌、zeta电位、跨血脑屏障入脑能力进行评价。结果得出,Tat-PEG-GS NPs粒径分布在150～200nm、zeta电位(32.27±2.47)mV;TEM观察显示Tat-PEG-GS NPs可跨过血脑屏障到达脑组织,活体成像显示Tat-PEG-GS NPs较PEG-GS NPs在脑部的荧光强,Tat-PEG-GS NPs比PEG-GS NPs在肝脏、脾脏的荧光低,差异具有统计学意义。证明Tat-PEG-GS NPs可以逃逸内皮网状吞噬系统的吞噬,跨过血脑屏障到达脑实质内,是一种有潜力的入脑纳米载体系统。     

HPMA‐PEG Surfmers and Their Use in Stabilizing Fully Biodegradable Polymer Nanoparticles

The most adopted methods to produce polymer nanoparticles (NPs) for medical and pharmaceutical applications use surfactants that are toxic and physically adsorbed to the NPs, with the risk of desorption and insurgence of side effects. A valid alternative is represented by the use of surfmers, reactive surfactants that are chemically linked to the polymer chains, thus avoiding the release of toxic species. In this case, the lack of biodegradable surfmers introduces the concern of polymer accumulation into the body. In this work, biodegradable, poly(ethylene glycol) (PEG)ylated N‐(2‐hydroxypropyl) methacrylamide (HPMA) based surfmers are synthesized and used to stabilize lipophilic NPs. In particular, the NP core is made from a macromonomer comprising a poly(lactic acid) (PLA) chain functionalized with HPMA double bond. The NP forming polymer chains are then constituted by a uniform poly(HPMA) backbone that is biocompatible and water soluble and hydrolysable PEG and PLA pendants assuring the complete degradability of the polymer. The stability provided to these NPs by the synthesized surfmers is studied in the cases of both emulsion free radical polymerization and solution free radical polymerization followed by the flash nanoprecipitation of the obtained amphiphilic copolymers.     

Supramolecular assemblies of histidinylated β-cyclodextrin for enhanced oligopeptide delivery into osteoclast precursors

Much attention has been given to the problem of drug delivery through the cell membrane in order to treat and manage bone diseases recently. The aim of this study was to develop nanoparticles made of amino- and histidinyl-modified amphiphilic β-cyclodextrins (β-CDs) entrapping osteoclast inhibitor, a hydrophobic oligopeptides drug, across the membrane of bone marrow-derived macrophages (BMMs). Drug-loaded β-CDs nanoparticles (NPs) were prepared by the emulsion solvent evaporation technique and fully characterized for size, zeta potential, and entrapment efficiency. Spherical NPs displaying a hydrodynamic radius of about 295 nm which did not change upon storage as an aqueous dispersion, a positive zeta potential, and entrapment efficiency of drug very close to 98% were produced. Flow cytometry and spectrofluorimetry analysis indicated that the model drug itself was not taken up by the BMMs; however, NP systems underwent significant cellular uptake. In particular, histidinyl group-modified CD (β-CD-H) NPs were taken up more efficiently than amino group-modified (β-CD-A) ones. Cellular uptake mechanism study demonstrated that the permeability of drug-loaded NPs across the membrane of BMMs is probably due to macropinocytosis pathway. Cell viability studies showed that both β-CD-A and β-CD-H exhibited no significant cytotoxicity up to 1.0 mg/ml against the cells. These results highlight the developed β-CD-H NPs have great potential in safely and effectively delivering osteoclast inhibitors and other therapeutic agents toward bone disease.