Design of a Tumor Homing Cell-Penetrating Peptide for Drug Delivery

The major drawbacks with conventional cancer chemotherapy are the lack of satisfactory specificity towards tumor cells and poor antitumor activity. In order to improve these characteristics, chemotherapeutic drugs can be conjugated to targeting moieties e.g. to peptides with the ability to recognize cancer cells. We have previously reported that combining a tumor homing peptide with a cell-penetrating peptide yields a chimeric peptide with tumor cell specificity that can carry cargo molecules inside the cells. In the present study, we have used a linear breast tumor homing peptide, CREKA, in conjunction with a cell-penetrating peptide, pVEC. This new chimeric peptide, CREKA–pVEC, is more convenient to synthesize and moreover it is better in translocating cargo molecules inside cancer cells as compared to previously published PEGA–pVEC peptide. This study demonstrates that CREKA–pVEC is a suitable vehicle for targeted intracellular delivery of a DNA alkylating agent, chlorambucil, as the chlorambucil–peptide conjugate was substantially better at killing cancer cells in vitro than the anticancer drug alone.     

Inorganic Porous Nanoparticles for Drug Delivery in Antitumoral Therapy

The use of nanoparticles in oncology to deliver chemotherapeutic agents has received considerable attention in the last decades due to their tendency to be passively accumulated in solid tumors. Besides this remarkable property, the surface of these nanocarriers can be decorated with targeting moieties capable to recognize malignant cells which lead to selective nanoparticle uptake mainly in the diseased cells, without affecting the healthy ones. Among the different nanocarriers which have been developed with this purpose, inorganic porous nanomaterials constitute some of the most interesting due to their unique properties such as excellent cargo capacity, high biocompatibility and chemical, thermal and mechanical robustness, among others. Additionally, these materials can be engineered to present an exquisite control in the drug release behavior placing stimuli-responsive pore-blockers or sensitive hybrid coats on their surface. Herein, the recent advances developed in the use of porous inorganic nanomedicines will be described in order to provide an overview of their huge potential in the look out of an efficient and safe therapy against this complex disease. Porous inorganic nanoparticles have been designed to be accumulated in tumoral tissues; once there to recognize the target cell and finally, to release their payload in a controlled manner.     

细胞穿膜肽介导蛋白/多肽类药物输送的研究进展

在当前药物研发中,蛋白/多肽类药物占据着重要地位。然而,此类药物大多需进入细胞内才能发挥作用,故细胞摄取率低的问 题成为制约其发展的关键因素。细胞穿膜肽是一类富含精氨酸的短肽,自身具有较强的生物膜穿透能力,可携带多种大分子甚至是纳米 粒入胞。因此,穿膜肽被广泛应用于药物输送,且基于穿膜肽介导药物胞内输送,成为解决蛋白/多肽类药物入胞问题的优选策略。主 要综述穿膜肽介导蛋白/多肽类药物输送用于不同疾病治疗的研究进展。     

生物可降解聚合物纳米粒给药载体

生物可降解聚合物纳米粒用于给药载体具有广阔的前景。本文综述了生物可降解聚合物纳米粒给药载体领域的最新进展 :包括纳米粒表面修饰特性、药物释放、载多肽和蛋白质等生物大分子药物传输中的潜在应用。     

Preparation and Evaluation of Miconazole Nitrate-Loaded Solid Lipid Nanoparticles for Topical Delivery

The purpose of this study was to prepare miconazole nitrate (MN) loaded solid lipid nanoparticles (MN-SLN) effective for topical delivery of miconazole nitrate. Compritol 888 ATO as lipid, propylene glycol (PG) to increase drug solubility in lipid, tween 80, and glyceryl monostearate were used as the surfactants to stabilize SLN dispersion in the SLN preparation using hot homogenization method. SLN dispersions exhibited average size between 244 and 766 nm. All the dispersions had high entrapment efficiency ranging from 80% to 100%. The MN-SLN dispersion which showed good stability for a period of 1 month was selected. This MN-SLN was characterized for particle size, entrapment efficiency, and X-ray diffraction. The penetration of miconazole nitrate from the gel formulated using selected MN-SLN dispersion as into cadaver skins was evaluated ex-vivo using franz diffusion cell. The results of differential scanning calorimetry (DSC) showed that MN was dispersed in SLN in an amorphous state. The MN-SLN formulations could significantly increase the accumulative uptake of MN in skin over the marketed gel and showed a significantly enhanced skin targeting effect. These results indicate that the studied MN-SLN formulation with skin targeting may be a promising carrier for topical delivery of miconazole nitrate.     

药物输送系统中Janus纳米粒子的制备及应用

Janus纳米粒子(Janus nanoparticle,JNP)用于描述由两个不同侧面组合而成的一种异质结构的实体材料。Janus纳米粒子每个侧面在化学性质和/或极性上都有所差异,可将不同材料的特征和功能结合在一起,这是同类均质的材料难以实现的。近年来,Janus纳米粒子的制备方法已取得了重大突破,但其应用的发展方向仍然是一个充满挑战的领域,其中在抗肿瘤药物输送系统领域的研究较为突出。主要介绍了在药物输送系统中Janus纳米粒子的制备方法及应用,并提出了研究前景和可能面临的挑战。     

综述——纳米材料与药物输递：基于聚合物的环境敏感型纳米抗肿瘤药物传输系统的研究

环境敏感型聚合物纳米抗肿瘤药物传递系统能够响应外界环境的微小刺激,引起自身结构的变化,释放出药物,在肿瘤治疗方面具长效低毒、可控及高载药量等优势,已被广泛应用于生物医学领域．本文介绍了聚合物环境响应型纳米药物传输系统的发展近况,并从pH 值敏感型、温度敏感型、氧化还原敏感型、酶敏感型以及其他敏感型给药系统角度,阐述了环境敏感型药物传输系统在抗肿瘤领域的研究现状及未来展望．     

pSP偶联低分子量壳聚糖介导siRNA对靶基因的沉默

放射性标记针对荧光素酶报告基因（Luc）的siRNA,与不同分子量的壳聚糖（CS）制备成CS/siRNA复合物,转染可稳定表达Luc基因的MDA-MB-231/Luc人乳腺癌细胞系.与 较大分子量壳聚糖相比,低分子量壳聚糖（LMWC）与siRNA形成的复合物具有更小的粒径及更强的siRNA转染能力,但是对靶基因的沉默效应却不高. 其原因归咎于低分子量壳聚糖（Mr为2 000或5 000,LMWC）与siRNA间强烈的电荷引力限制了siRNA在细胞内的释放.合成基序为LLLRRRDNEY*FY*VRRLL的可磷酸化短肽(pSP)与LMWC相偶联,合成pSP-LMWC.分别对siRNA及pSP-LMWC进行FAM及Dabcyl标记,利用FRET技术检测细胞内pSP-LMWC与siRNA的解离.结果表明,pSP修饰可大幅度增加siRNA与LMWC在细胞内的解离,成为有功能的游离形式,从而显著下调靶基因的表达.本文的结果表明,低分子量壳聚糖具有良好的siRNA递送能力,促进其与siRNA在细胞内的解离可有效提高siRNA对靶基因的沉默效应.     

中空硅纳米药物递送体系的线粒体靶向性探究

目的:探究中空硅纳米粒在细胞线粒体内的定位。方法:以阿霉素为模型药物及荧光影像分子,通过激光共聚焦显微镜,考察中空硅纳米粒与线粒体分子探针在线粒体内的共定位。通过差速离心法提取线粒体,进一步确认硅纳米粒在线粒体内的聚集。结果:与线粒体分子探针为共定位参照,中孔硅纳米粒在线粒体中分布的皮尔逊系数为0.758±0.033,线粒体提取结果显示,进入细胞的纳米粒有90.01±3.89%分布于线粒体。结论:中空硅纳米粒具有自发聚集于线粒体的能力,可以作为药物靶向递送载体,为线粒体类疾病的治疗提供新的平台。     

巯基化壳聚糖季铵盐用于基因输送的研究

目的:本研究诣在对壳聚糖进行修饰,以解决其水溶性问题和基因释放困难的问题。方法:本研究通过2,3-环氧丙基三甲基氯化铵和N-乙酰-L-半胱氨酸对壳聚糖进行修饰,得到巯基化壳聚糖季铵盐(TMC-SH),使其在生理条件下带正电并含有一定量的游离巯基。以TMC-SH为基因载体,形成基因复合物。通过琼脂糖凝胶电泳考察其稳定性,并测定其粒径和ζ-电位。通过DTT条件下的粒径测定,考察基因复合物的还原响应性。结果:核磁结果表明合成TMC-SH的季铵盐取代度为22%,游离巯基-SH含量为79.22μmol/g;琼脂糖凝胶电泳结果表明以TMC-SH为载体形成的二硫键交联的基因复合物TMC-SS/p DNA具有较好的稳定性;而且,二硫键交联以后基因复合物粒径较小,结构更为密实;在还原条件下粒径变大,表明二硫键交联的基因复合物变得疏松,说明其粒径具有还原响应性。结论:对壳聚糖进行低取代度的季铵盐修饰和一定量的巯基化修饰后,其具有较好的包载p DNA能力和还原响应性的基因释放能力。     

Effects of Orally Administered Bovine Lactoperoxidase on Dextran Sulfate Sodium-Induced Colitis in Mice

The effect of lactoperoxidase (LPO) on dextran sulfate sodium-induced colitis was examined in mice. After 9 d of colitis induction, weight loss, colon shortening, and the histological score were significantly suppressed in mice orally administered LPO (62.5 mg/body/d) as compared to a group administered bovine serum albumin. These results suggest that LPO exhibits anti-inflammatory effects in the gastrointestinal tract.     

利用纳米材料制作多肽疫苗佐剂的思考

纳米粒子与生物体有着密切的关系,DNA/蛋白质复合体就在15～20 nm之间,多种病毒颗粒也是纳米级的超微粒子.多肽抗原需要与适当载体形成复合物才能诱导有效的免疫应答,但载体效应难以避免.纳米佐剂可以避免载体效应的发生,而且还是巨噬细胞(Mφ)、树突状细胞(DC)的首选吞噬目标.纳米化的有机药物可提高其生物利用度、制剂的均匀性、分散性和吸收性;脂质体可使药物更快地到达靶向部位,而且特异性更强.目前主要用理化的方法制作纳米材料,几乎所有的生化药品,特别是DNA药物的研究开发都可引入纳米材料,多肽疫苗的分子佐剂更是如此.     

Chitosan nanoparticles for oral drug and gene delivery

Chitosan is a widely available, mucoadhesive polymer that is able to increase cellular permeability and improve the bioavailability of orally administered protein drugs. It can also be readily formed into nanoparticles able to entrap drugs or condense plasmid DNA. Studies on the formulation and oral delivery of such chitosan nanoparticles have demonstrated their efficacy in enhancing drug uptake and promoting gene expression. This review summarizes some of these findings and highlights the potential of chitosan as a component of oral delivery systems.     

多肽和蛋白质药物的吸入给药

概述了多肽和蛋白质药物的肺吸收机制和用于吸入给药的研究进展,并简要讨论了多肽和蛋白质药物在用于吸入给药时存在的问题及今后的发展方向,为多肽和蛋白质药物的吸入给药研究提供一定的参考。     

Intracellular Delivery of Nanoparticles of an Antiasthmatic Drug

The aim of the investigation was to prepare and characterize wheat germ agglutinin(WGA)-conjugated poly(d,l-lactic-co-glycolic) acid nanoparticles encapsulating mometasone furoate (MF) as a model drug and assess changes in its fate in terms of cellular interactions. MF loaded nanoparticles were prepared using emulsion–solvent evaporation technique. WGA-conjugation was done by carbodiimide coupling method. The nanoparticles were characterized for size, zeta potential, entrapment efficiency and in-vitro drug release. The intracellular uptake of nanoparticles, drug cellular levels, and anti-proliferative activity studies of wheat germ agglutinin-conjugated and unconjugated nanoparticles were assessed on alveolar epithelial (A549) cells to establish cellular interactions. Prepared nanoparticles were spherical with 10–15 μg/mg of WGA conjugated on nanoparticles. The size of nanoparticles increased after conjugation and drug entrapment and zeta potential reduced from 78 ± 5.5% to 60 ± 2.5% and −15.3 ± 1.9 to −2.59 ± 2.1 mV respectively after conjugation. From the cellular drug concentration–time plot, AUC was found to be 0.4745, 0.6791 and 1.24 for MF, MF-nanoparticles and wheat germ agglutinin-MF-nanoparticles respectively. The in-vitro antiproliferative activity was improved and prolonged significantly after wheat germ agglutinin-conjugation. The results conclusively demonstrate improved availability and efficacy of antiasthmatic drug in alveolar epithelial cell lines. Hence, a drug once formulated as mucoadhesive nanoparticles and incorporated in dry powder inhaler formulation may be used for targeting any segment of lungs for more improved therapeutic response in other lung disorders as well.     

Nanoparticles for bone tissue engineering

Tissue engineering (TE) envisions the creation of functional substitutes for damaged tissues through integrated solutions, where medical, biological, and engineering principles are combined. Bone regeneration is one of the areas in which designing a model that mimics all tissue properties is still a challenge. The hierarchical structure and high vascularization of bone hampers a TE approach, especially in large bone defects. Nanotechnology can open up a new era for TE, allowing the creation of nanostructures that are comparable in size to those appearing in natural bone. Therefore, nanoengineered systems are now able to more closely mimic the structures observed in naturally occurring systems, and it is also possible to combine several approaches ‐ such as drug delivery and cell labeling ‐ within a single system. This review aims to cover the most recent developments on the use of different nanoparticles for bone TE, with emphasis on their application for scaffolds improvement; drug and gene delivery carriers, and labeling techniques. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:590–611, 2017     

Development and Characterization of Pectinate Micro/Nanoparticles for Gene Delivery

The aim of this study was to investigate the possibility of using pectinate micro/nanoparticles as gene delivery systems. Pectinate micro/nanoparticles were produced by ionotropic gelation. Various factors were studied for their effects on the preparation of pectinate micro/nanoparticles: the pH of the pectin solution, the ratio of pectin to the cation, the concentration of pectin and the cation, and the type of cation (calcium ions, magnesium ions and manganese ions). After the preparation, the size and charge of the pectin micro/nanoparticles and their DNA incorporation efficiency were evaluated. The results showed that the particle sizes decreased with the decreased concentrations of pectin and cation. The type of cations affected the particle size. Sizes of calcium pectinate particles were larger than those of magnesium pectinate and manganese pectinate particles. The DNA loading efficiency showed that Ca-pectinate nanoparticles could entrap DNA up to 0.05 mg when the weight ratio of pectin:CaCl₂:DNA was 0.2:1:0.05. However, Mg-pectinate could entrap only 0.01 mg DNA when the weight ratio of pectin:MgCl₂:DNA was 1:100:0.01 The transfection efficiency of both Ca-pectinate and Mg-pectinate nanoparticles yielded relatively low levels of green fluorescent protein expression and low cytotoxicity in Huh7 cells. Given the negligible cytotoxic effects, these pectinate micro/nanoparticles can be considered as potential candidates for use as safe gene delivery carriers.     

Chitosan and lactic acid-grafted chitosan nanoparticles as carriers for prolonged drug delivery

Nanoparticles of approximately 10nm in diameter made with chitosan or lactic acid-grafted chitosan were developed for high drug loading and prolonged drug release. A drug encapsulation efficiency of 92% and a release rate of 28% from chitosan nanoparticles over a 4-week period were demonstrated with bovine serum protein. To further increase drug encapsulation, prolong drug release, and increase chitosan solubility in solution of neutral pH, chitosan was modified with lactic acid by grafting D,L-lactic acid onto amino groups in chitosan without using a catalyst. The lactic acid-grafted chitosan nanoparticles demonstrated a drug encapsulation efficiency of 96% and a protein release rate of 15% over 4 weeks. With increased protein concentration, the drug encapsulation efficiency decreased and drug release rate increased. Unlike chitosan, which is generally soluble only in acid solution, the chitosan modified with lactic acid can be prepared from solutions of neutral pH, offering an additional advantage of allowing proteins or drugs to be uniformly incorporated in the matrix structure with minimal or no denaturization.     

A Novel Nanoparticle Formulation for Sustained Paclitaxel Delivery

Purpose  To develop a novel nanoparticle drug delivery system consisting of chitosan and glyceryl monooleate (GMO) for the delivery of a wide variety of therapeutics including paclitaxel. Methods  Chitosan/GMO nanoparticles were prepared by multiple emulsion (o/w/o) solvent evaporation methods. Particle size and surface charge were determined. The morphological characteristics and cellular adhesion were evaluated with surface or transmission electron microscopy methods. The drug loading, encapsulation efficiency, in vitro release and cellular uptake were determined using HPLC methods. The safety and efficacy were evaluated by MTT cytotoxicity assay in human breast cancer cells (MDA-MB-231). Results  These studies provide conceptual proof that chitosan/GMO can form polycationic nano-sized particles (400 to 700 nm). The formulation demonstrates high yields (98 to 100%) and similar entrapment efficiencies. The lyophilized powder can be stored and easily be resuspended in an aqueous matrix. The nanoparticles have a hydrophobic inner-core with a hydrophilic coating that exhibits a significant positive charge and sustained release characteristics. This novel nanoparticle formulation shows evidence of mucoadhesive properties; a fourfold increased cellular uptake and a 1000-fold reduction in the IC₅₀ of PTX. Conclusion  These advantages allow lower doses of PTX to achieve a therapeutic effect, thus presumably minimizing the adverse side effects.     

纳米基因转运体——原理、研制与应用

基因转移是基因治疗的关键技术,一直以来也是制约基因治疗成功开展的瓶颈问题.随着纳米技术的发展,纳米基因转运体的研制获得了积极发展,其系统内和细胞内基因转移机理得到了深入阐明.设计与研制在体内循环时间长、具有靶特异性的纳米转运体为突破基因转移瓶颈,实现安全、高效和靶向性基因治疗带来了新的希望.