pH敏感型热休克笼形蛋白纳米载体的构建及其理化性质评价

目的 设计并制备具有靶向肿瘤且pH敏感的热休克蛋白（heat shock proteins,HSP）笼形蛋白纳米递药系统,并对其理化性质进行表征。方法 采用基因全合成与蛋白质重组表达技术纯化HSP为母版,通过表面官能团功能化制备得到修饰穿膜肽Tat、聚乙二醇包衣的热休克笼形蛋白纳米载体（PT-HSP）。通过透射电镜、纳米粒度与Zeta电位测定仪对其形态、粒径及Zeta电位进行表征,并建立HPLC测定其载药量与包封率。考察载紫杉醇（paclitaxel,PTX）的PT-HSP在生理pH条件（pH 7.4）与肿瘤pH条件（pH 6.5）下的体外释药行为。结果 形态学结果表明,PT-HSP是呈现典型双层结构的均一球体,平均粒径为（154.4±23.6） nm,Zeta电位为（-2.6±0.7） mV。HPLC测得载PTX的PT-HSP的包封率为（75.3±3.6）%,载药量为（7.0±0.2）%。体外释药试验结果表明PT-HSP在pH 7.4条件下的释放速率显著慢于pH 6.5条件下的释放速率（P<0.01）。结论 本研究制备得到的pH敏感的HSP笼形蛋白智能纳米递药系统具有载药量高、稳定性强及智能靶向等优点,有望成为一种安全、有效、智能的抗肿瘤药物载体。     

Near-infrared imaging of diseases: A nanocarrier approach

Developments in fluorescence imaging, brought popularity to near infrared (NIR) imaging with far-red and NIR fluorophores applied for biosensing and bioimaging in living systems. Noninvasive NIR imaging gained popularity with the use of effective NIR dyes to obtain macroscopic fluorescence images. Several attributes of NIR dyes make them desirable agents, including high specificity, high sensitivity, minimized background interference, and the ability to easily conjugate with drug delivery systems. However, NIR dyes have some drawbacks and limitations, such as low solubility, low stability, and degradation. To overcome these issues, NIR dyes can be encapsulated in appropriate nanocarriers to achieve effective diagnosis, imaging, and therapy monitoring during surgery. Moreover, the vast majority of NIR dyes have photosensitizer features that can effectuate cancer treatment referred to as photodynamic therapy (PDT). In the near future, by combining NIR dyes with appropriate nanocarriers such as liposomes, polymeric micelles, polymeric nanoparticles, dendrimers, quantum dots, carbon nanotubes, or ceramic/silica based nanoparticles, the limitations of NIR dyes can be minimized or even effectively eliminated to form potential effective agents for imaging, therapy, and therapy monitoring of several diseases, particularly cancer.     

蛋白质类纳米载体材料的研究进展

纳米技术为制药领域、特别是药物输送领域提供了新的策略,其中,蛋白质作为药物分子的纳米载体备受关注。蛋白质纳米载药系统是以动物、植物或重组蛋白质为载体,与药物共同组成的纳米载药体系,具有良好的生物相容性、生物降解性、低抗原性、较高的稳定性及载药性等优点,在临床治疗尤其是肿瘤的靶向治疗等领域具有重要意义。本文从动物来源的蛋白质、植物来源的蛋白质以及重组蛋白质的理化性质、功能特性介绍入手,总结了蛋白质类纳米载体在药物递送载体中的应用现状,并探讨了蛋白质纳米载体的发展方向。     

Synthesis and characterization of self-assembled CdHgTe/gelatin nanospheres as stable near infrared fluorescent probes in vivo

This work presented a kind of novel near infrared emitting CdHgTe/gelatin nanospheres which were synthesized with Cd(NO₃)₂, Hg(NO₃)₂, NaHTe and a thiol stabilizer in gelatin solution. The self-assembled nanospheres were megranate-like and nearly 40 nm in diameter, with CdHgTe QDs uniformly embedded in gelatin matrix. They exhibited strong fluorescence ranging from 580 to 800 nm that could be tuned by molar ratios of Hg²⁺ and gelatin. The full widths at half-maximum of the emission spectra were in the range of 60–80 nm. Compared with bare CdHgTe QDs, the photostability of this compact complex nanostructure remarkably improved. Moreover, the fluorescence of CdHgTe/gelatin nanospheres was much more resistant to the interference from certain kinds of endogenous biomolecules such as HSA, transferrin and hemoglobin. Further applications of living cells and mouse imaging were demonstrated with an in vivo near infrared fluorescence imaging system. The inherent advantages of high stability as well as high fluorescence intensity make the nanospheres particular interested NIR bioprobe candidates for in vivo imaging studies.     

类脂囊泡在不同给药途径中的研究进展

纳米载体具有靶向递送药物至特定部位的潜力,因此纳米载体的开发一直受到广泛关注。近10年里,制备基于表面活性剂的纳米囊泡以改善药物递送,引起了研究者们的兴趣。类脂囊泡由非离子表面活性剂在水性介质中自组装形成,具有既能包裹亲水性化合物又能包裹亲脂性化合物的囊泡结构,广泛应用于各种给药途径。与脂质体相比,类脂囊泡不仅具有与其相似的优点,如既能装载亲水性药物又能装载亲脂性药物,而且类脂囊泡的制备方法更简单,制备原料价格更便宜,稳定性更好,克服了脂质体的主要缺点。本文综述了类脂囊泡各制备方法的优缺点及其在不同给药途径中的研究进展。     

甘草次酸修饰马钱子碱纳米给药系统的体内外肝靶向性评价

目的 制备甘草次酸（GA）修饰的马钱子碱（B）-聚乙二醇-二硫代二丙酸-单硬脂酸甘油酯（PSG）纳米粒（NPs）（B-GPSG-NPs）并评价其体内外肝靶向性。方法 采用溶剂乳化超声法制备B-GPSG-NPs和B-PSG-NPs,于透射电镜下观察其外观形态,测定其粒径、多分散性指数（PDI）、Zeta电位、包封率、载药量等理化性质。建立检测心、肝、脾、肺、肾、脑组织中马钱子碱含量的高效液相色谱法。将雌雄各半的小鼠90只随机分为3组：马钱子碱组、B-PSG-NPs组、B-GPSG-NPs组,禁食不禁水12h后,尾iv相应溶液（以马钱子碱计10mg·kg^-1）,分别于给药后10、30、60、120、180min取各组织进行HPLC检测,计算相对摄取率（Re）和靶向效率（Te）,以评价给药系统的体内靶向性。制备载异硫氰基荧光素（FITC）的FITC-B-PSG-NPs、FITC-B-GPSG-NPs,FITC、空白PSG载体制成的纳米粒（PSG-NPs）、空白GPSG载体制成的纳米粒（GPSG-NPs）以及含马钱子碱质量浓度分别为500、250、125μg·mL^-1的FITC-B-PSG-NPs和FITC-B-GPSG-NPs与CBRH-7919肝癌细胞共培养24h,荧光显微镜下观察CBRH-7919细胞对各受试物的摄取情况,以评价给药系统的体外靶向性。结果 B-GPSG-NPs的粒径为（98.91±3.62）nm,呈正态分布;PDI值为（0.221±0.006）,Zeta电位为-（19.63±0.40）mV,包封率为（78.37±1.83）%,载药量为（2.86±0.05）%;B-PSG-NPs与B-GPSG-NPs组肝脏的Re分别为1.49和1.72,明显高于其他组织;马钱子碱组肾脏Te最高,脑Te最低,而B-PSG-NPs和B-GPSG-NPs组肝脏中马钱子碱的Te明显高于其他各组织;CBRH-7919细胞摄取B-GPSG-NPs效率明显高于B-PSG-NPs,并表现出剂量相关性。结论 制备的BGPSG-NPs在体内外均表现出良好的肝靶向效应,且优于无GA修饰的B-PSG-NPs。     

细胞外激活纳米载药系统研究进展

隐蔽性和靶向性对于纳米载体能否高效、选择性的递送药物非常重要,然而,传统方法难以让纳米载体同时具备这两种性质。新型靶向技术的迅速发展有望克服这一难点。本文在回顾传统靶向技术,阐述其取得的成果和面临的瓶颈的同时,着重讨论了利用环境刺激来激活的新型纳米载体的研究进展。     

纳米载体提高难溶性药物口服生物利用度的研究进展

纳米载体是药剂学备受关注的研究领域,作为一类新型给药系统,它能显著提高难溶性药物的溶解度、生物利用度和稳定性,且具有明显的缓释作用,因此得到了广泛的应用.目前常用于提高难溶性药物口服生物利用度的纳米载体有纳米脂质体、固体脂质纳米粒、纳米胶束、和纳米结晶等,它们的粒径、表面性质及其释药环境等是影响纳米载体药物口服吸收的主...     

Multifunctional pH-disintegrable micellar nanoparticles of asymmetrically functionalized β-cyclodextrin-based star copolymer covalently conjugated with doxorubicin and DOTA-Gd moieties

We report on a novel type of multifunctional pH-disintegrable micellar nanoparticles fabricated from asymmetrically functionalized β-cyclodextrin (β-CD) based star copolymers covalently conjugated with doxorubicin (DOX), folic acid (FA), and DOTA-Gd moieties for integrated cancer cell-targeted drug delivery and magnetic resonance (MR) imaging contrast enhancement. Asymmetrically functionalized β-CD, (N₃)₇-CD-(Br)₁₄, which possesses 7 azide functionalities and 14 α-bromopropionate moieties in the upper and lower rim of rigid toroidal β-CD core, respectively, was synthesized at first. The subsequent atom transfer radical polymerization (ATRP) of N-(2-hydroxypropyl) methacrylamide (HPMA), conjugation with DOX and FA, and click reaction with alkynyl-(DOTA-Gd) complex afforded (DOTA-Gd)₇-CD-(PHPMA-FA-DOX)₁₄ star copolymer comprising of 7 DOTA-Gd complex moieties and 14 PHPMA arms covalently anchored with DOX and FA via acid-labile carbamate linkages and ester bonds, respectively. The covalent conjugation with ∼13 DOX molecules onto PHPMA arms per star copolymer (∼14 wt% loading content) endows the initially hydrophilic one with amphiphilicity, leading to the self-assembly into micellar nanoparticles of several tens of nanometers in aqueous solution at pH 7.4. In vitro DOX release profile from micellar nanoparticles is highly pH-dependent, and over a time period of 42 h, cumulative releases of ∼10%, 53%, and 89% conjugated DOX at pH 7.4, 5.0, and 4.0, respectively, were observed. Most importantly, the pH-modulated release of conjugated DOX from micellar nanoparticles is accompanied with the micelle disintegration due to the loss of amphiphilicity of the star copolymer scaffold. In vitro cell viability assays revealed that (DOTA-Gd)₇-CD-(PHPMA₁₅)₁₄ star copolymer is almost non-cytotoxic up to a concentration of 0.5 g/L, whereas DOX-conjugated micellar nanoparticles of (DOTA-Gd)₇-CD-(PHPMA-FA-DOX)₁₄ can effectively enter and kill HeLa cells at a concentration higher than ∼80 mg/L. In vitro MR imaging experiments indicated a considerably enhanced T₁ relaxivity (r₁ = 11.4 s⁻¹ mM⁻¹) for micellar nanoparticles compared to that for the small molecule counterpart, alkynyl-DOTA-Gd (r₁ = 3.1 s⁻¹ mM⁻¹). In vivo MR imaging assay in rats revealed considerable accumulation of micellar nanoparticles within rat liver and kidney and prominent positive contrast enhancement. The integrated design of diagnostic and therapeutic functions of multifunctional pH-disintegrable micellar nanoparticles augurs well for their practical applications in the field of image-guided cancer chemotherapy.     

Brain targeted solid lipid nanoparticles for brain ischemia: preparation and in vitro characterization

This study aims at formulating solid lipid nanoparticles (SLNs) of Vinpocetine (VIN) to be used as a brain targeted sustained drug-delivery system. VIN is a derivative of vincamine alkaloid, used for chronic cerebral vascular ischemia. However, it suffers from low bioavailability and short half-life. Its oral bioavailability is recorded to be between 7 and 55%. Its elimination half-life is 1–2?h so it would be a good candidate for a sustained drug-delivery system. VIN SLNs were prepared using modified high shear homogenization followed by ultrasonication technique. The effect of incorporating different lipids at different concentrations of various surfactants was investigated. The VIN SLNs were characterized by entrapment efficiency percent (EE%), particle size distribution, zeta-potential, and cumulative released percent after 96?h. The EE% ranged between 83.34% ± 0.95–94.56% ± 0.11 due to the lipophilic character of VIN. The mean particle size measured ranged from 123 nm–464?nm. The cumulative released percent after 96?h ranged from 23.55% to 75.67% showing a controlled release profile. Formula (F32) composed of 5% glyceryl monostearate (GMS) and stabilized by 2% surfactant mixture [Tween 80, Pluronic F 68 (1:1)] was the most appropriate formula for brain delivery having EE% of 89.09% ± 1.49, zero-order release kinetics with cumulative released percent of 72.12% after 96?h, zeta-potential of –11.3?±?0.97 mV. It showed a unimodal size distribution with particle size ≈90?nm and polydispersity index of 0.121. The formula of choice in this study exhibited a zero-order sustained release profile and met the requirement for a brain targeted SLN so it could be a promising formula to deliver VIN to the brain.