聚焦超声联合微泡开放血脑屏障增强脑靶向递送研究进展

血脑屏障(blood-brain barrier, BBB)是药物脑靶向递送的最主要屏障,聚焦超声和微泡联合应用为跨BBB脑靶向递送提供了一种新途径,其主要机制为空化效应.本综述概括了近年来采用聚焦超声联合微泡增强BBB通透性实现药物脑靶向递送的相关研究,详细论述了聚焦超声及其作用机制;商品化微泡种类、常用微泡膜材、内...     

超声微泡造影剂介导基因靶向治疗肝细胞癌的研究进展

随着超声造影及微泡制备技术的不断发展,超声微泡造影剂携带基因和药物的靶向治疗成为当前医学领域中的研究热点.利用超声波与微泡造影剂的相互作用及所产生的生物学效应,可实现微泡携带基因向目标组织转移释放,使肿瘤细胞局部目的基因的浓度大大增高,达到靶向治疗目的.     

超声微泡介导基因转移在骨折创伤愈合中的应用

随着分子生物学的深入研究,基因治疗在医学领域具有广阔的应用前景。超声微泡介导基因转移是将携带有目的基因的微泡造影剂经静脉注射传递到靶组织后,利用超声波在靶区破坏微泡,实现体内局部组织目的基因转移及促进表达的技术。     

超声介导微泡靶向药物释放的应用研究进展

随着基因治疗学及分子生物学的迅速发展,无创性治疗基因靶向传输技术在不断进步,超声微泡除可广泛应用于疾病的诊断以外,还被证实是一种有效的靶向释放药物和基因载体[1～4].药物与微泡的结合方式有2种:一是直接粘附于微泡外壳;二是与特异性配体结合.     

微泡超声造影剂的研究进展

根据近年来微泡超声造影剂的国外研究进展，阐述了微泡超声造影剂的制法、靶向制备技术、体内过程和物理原理，并讨论了其在治疗上的应用和发展前景。     

含气微泡介导反义寡核苷酸转染实验的参数优化

近年的研究表明，含气微泡在超声作用下的声孔效应（sonorporation）可明显增加基因的转染率，不仅安全性高，而且针对不同的基因具有定位和时空可控性。利用含气微泡作为基因与药物的超声靶向递送的载体，要求微泡的包膜材料在包裹气体的同时还必须具有足够的韧性和强度，使其在体内外都能保持一定的稳定性，特别是能克服体内动脉压力的影响。     

超声微泡和超声空化效应在生物医学中的应用探讨

随着新型超声技术和超声对比剂的研究和在医学领域中的广泛应用,超声对比剂和空化效应联合运用,作为一种新型治疗手段,具有安全、高效、操作简单的优势,在药物输送、基因治疗以及肿瘤和炎症的靶向治疗中显示了巨大的应用价值。本文参考近几年文献,综述了超声微泡和超声空化效应的治疗机制及其应用。     

一种新的药物传递系统——超声微泡剂

目的：探讨超声微泡剂作为药物载体传输药物的机制及临床应用前景。方法：查阅国内外文献，进行归纳总结，分析其作用机制及应用前景。结果：超声微泡剂可作为药物载体，可传输基因和药物，能提高基因的转染率和表达，配合超声处理产生的空化效应可提高细胞膜的通透性，利于药物穿透；并且具有靶向性。因此在基因治疗和抗肿瘤治疗方面有很好的应用前景。结论：随着超声技术和微泡剂制备技术的发展，超声微泡剂必将为临床治疗提供一种安全、高效、无创的超声介导靶向传输及治疗系统。     

超声微泡用于脑胶质瘤靶向药物递送

本文用超声微泡可逆地有限开放血脑屏障(blood-brain barrier,BBB),为抗肿瘤药物的脑内靶向递送打下基础。建立脑胶质瘤大鼠模型,探索低频超声(1 MHz)结合微泡对脑胶质瘤部位BBB开放的影响,并与非超声条件下伊文思蓝(Evans blue,EB)渗透BBB对比。考察超声的时机和时长对BBB渗透和脑组织的损伤作用。考察脑胶质瘤生长期对BBB渗透性的影响。结果表明,脑胶质瘤对BBB渗透性影响非常有限;而超声微泡可短暂有限开放BBB,并具有可逆性,可促进EB和核磁增强造影剂渗透BBB。超声时长30 s最合适,可开放BBB,并且对脑组织不会造成明显损伤。药物需在超声前注射才能借助BBB开放进入脑。超声微泡可安全有效开放BBB,控制时机和时长,能促进药物进入脑胶质瘤和脑组织。     

超声靶向微泡破碎联合半乳糖聚乙烯亚胺介导EGFP质粒转染肝癌细胞的研究

目的 探讨超声靶向微泡破碎(UTMD)联合半乳糖聚乙烯亚胺(PEI-Gal)介导pEGFP-N3质粒转染肝癌细胞HepG2的效率及对细胞增殖的影响.方法 体外培养HepG2细胞,随机分为6组:(1)空白对照组(C);(2)超声(U)+微泡(M)组;(3) PEI-Gal(P)组;(4)P+M组;(5)P+U组;(6)P+U+M组.转染24 h后荧光显微镜观察HepG2细胞中绿色荧光蛋白质的表达,流式细胞术检测转染率,MTT法检测细胞活性.结果 P+U+M组转染率为(29.16±1.78)％,明显高于其他各组(P均＜0.05),U+M组转染率最低(15.63±1.81)％.P+U+M组存活率为(83.48±0.93)％,低于U+M组(86.37±1.56)％和P+U组的(89.54±0.91)％(P＜0.01).结论 UTMD联合PEI-Gal能显著增强pEGFP-N3质粒转染肝癌细胞HepG2的效率.     

声振脂质微泡作为反义寡核苷酸传递系统的研究

目的研究声振脂质微泡(PGM)作为反义寡核苷酸传递系统的可行性。方法应用PGM将结合荧光蛋白的反义核苷酸片段ZL转染到乳腺癌细胞SK-BR-3中，考察不同因素如：ZL浓度、PGM浓度、超声持续时间和机械指数(MI)等对ZL转染率及细胞存活率的影响。考察PGM的结果，并与其他脂质载体如lipofectamine和脂质体的转染效果比较。应用荧光显微镜观察转染率，碘化丙锭(PI)染色观察细胞存活率。结果考察因素中，PGM浓度，超声持续时间和MI对ZL转染率和细胞存活率影响较大。最佳超声条件为：PGM浓度为2%，超声持续时间为30 s和MI为1.0，在此条件下转染率为78%±10%，比未超声的PGM(4.0%)和lipofectamine(4.3%)的转染率增加了约18倍，而细胞存活率相近。结论在适宜条件下，声振脂质微泡可以有效促进体外反义核苷酸的转染。     

Ultrasound-mediated gene delivery

Importance of the field: The use of ultrasound with microbubbles raises the possibility of an efficient and safe gene delivery.

Areas covered in this review: This review summarizes the current state of the art of gene delivery by sonoporation under the following topics. First, the basic ultrasound parameters and the characteristics of microbubble in biological systems are discussed. Second, the extensions of sonoporation to other fields of gene delivery such as viral and non-viral vector are briefly reviewed. Finally, recent applications in an animal model for various diseases are introduced.

What the reader will gain: Information and comments on gene delivery by sonoporation or enhanced cell membrane permeability by means of ultrasound.

Take home message: Ultrasound-mediated gene delivery combined with microbubble agents provides significant safety advantages over other methods of local gene delivery.     

靶向基因转移系统的研究进展

基因治疗已在治疗多种人类重大疾病如遗传病、肿瘤等方面显示出良好的应用前景,但也面临着巨大的挑战,主要是如何选择安全、高效、靶向的载体系统。基因治疗的靶向性研究近年来取得了许多新的进展,如应用重组病毒载体,借助抗体或配体将治疗基因定向导入靶细胞。纳米生物材料由于其良好的生物安全性,可方便有效地实现基因的靶向性及高效表达,成为制备高效、靶向的基因治疗载体系统的良好介质,在基因治疗载体系统中日益受到广泛重视。本文综述了目前国内外在靶向基因转移系统中的最新研究进展。     

Recent advances in aerosol gene delivery systems using non-viral vectors for lung cancer therapy

ABSTRACT

Introduction: Lung cancer commonly occurs at a high incidence worldwide. Application of aerosol gene delivery systems using various kinds of vectors can improve the patient’s quality of life by prolonging the survival rate.

Areas covered: This review provides a recent update on aerosol gene delivery strategies using various kinds of vectors and gene-modification technologies. Peptide-mediated gene therapy achieves specific targeting of cells and highly improves efficacy. Promoter-operating expression and the CRISPR/Cas9 system are novel gene therapy strategies for effective lung cancer treatment. Furthermore, hybrid systems with a combination of vectors or drugs have been recently applied as new trends in gene therapy.

Expert opinion: Although aerosol gene delivery has many advantages, physiological barriers in the lungs pose formidable challenges. Targeted gene delivery and gene-editing technology are promising strategies for lung cancer therapy. These strategies may allow the development of safety and high efficiency for clinical application. Recently, hybrid gene therapy combining novel and specific vectors has been developed as an advanced strategy. Although gene therapy for lung cancer is being actively researched, aerosol gene therapy strategies are currently lacking, and further studies on aerosol gene therapy are needed to treat lung cancer.     

Optimization of ultrasound and microbubbles targeted gene delivery to cultured primary endothelial cells

Ultrasound and microbubbles targeted gene delivery (UMTGD) is a promising technique for local gene delivery. As the endothelium is a primary target for systemic UMTGD, this study aimed at establishing the optimal parameters of UMTGD to primary endothelial cells. For this, an in vitro ultrasound (US) setup was employed in which individual UMTGD parameters were systematically optimized. The criteria for the final optimized protocol were: (1) relative high reporter gene expression levels, restricted to the US exposed area and (2) induction of not more than 5% cell death. US frequency and timing of medium replacement had a strong effect on UMTGD efficiency. Furthermore, US intensity, DNA concentration and total duration of US all affected UMTGD efficiency. Optimal targeted gene delivery to primary endothelial cells can be accomplished with Sonovue® microbubbles, using 20 μg/ml plasmid DNA, a 1 MHz US exposure of Ispta 0.10 W/cm² for 30 s with immediate medium change after UMTGD. This optimized protocol resulted in both an increase in the number of transfected cells (more than three fold) and increased levels of transgene expression per cell (170%).     

基因物理靶向递送技术

应用非病毒物理方法进行基因递送已成为细胞内基因递送和基因治疗的基本手段。本文总结目前最常用的非病毒物理方法,重点阐述每种基因递送方法的机制,以及治疗应用中的优缺点。本文还对各种方法的技术特点进行总结,重点阐述了提高递送效率的改进方法,并简要探讨了本领域未来的发展方向。     

Recent advances in the development of polyethylenimine-based gene vectors for safe and efficient gene delivery

Introduction: Despite the great therapeutic potential of gene therapy for treating critical diseases, the clinical application is limited by lack of safe and effective gene delivery vectors. Nonviral gene vectors have attracted tremendous attention due to the favorable loading capacity and facile manufacture. Among them, polyethylenimine-based gene vectors (PEIs) hold great promise for highly efficient gene delivery.

Areas covered: In this review, we outline the multiple biological barriers associated with gene delivery process and point out several challenges exist in the clinical usage of PEIs. We then provide an overview of the most impressive progresses made to overcome such challenges in recent years, including modifications of PEIs (i.e. to enhance biocompatibility, specific targeting effect, and buffering capacity) and stimuli-responsive strategies (i.e. endogenous and exogenous stimuli) for safe and efficient gene delivery.

Expert opinion: Rational modification of PEIs with diverse functionalized segments or the development of stimuli-responsive PEIs is an appealing strategy to meet some requirements involved in gene delivery. Nevertheless, further optimization by combining the two strategies is needed for the maximized transfection efficiency and minimized side effects, shedding new light on the development of nonviral gene delivery for clinical application.     

Recent advances in brain tumor-targeted nano-drug delivery systems

Introduction: Brain tumors represent one of the most challenging and difficult areas in unmet medical needs. Fortunately, the past decade has seen momentous developments in brain tumor research in terms of brain tumor-targeted novel nano-drug delivery systems with significant important superiority over conventional formulations with respect to decreased toxicity and improved pharmacokinetics/pharmacodynamics.

Area covered: This review first introduces the characteristics of the two major obstacles in brain-tumor targeted delivery, blood–brain barrier (BBB) and blood–brain tumor barrier (BBTB), and then reviews recent advances in brain tumor-targeted novel nano-drug delivery systems according to their targeting strategies aimed at different stages of brain tumor development and growth.

Expert opinion: Based on continuously changing vascular characteristics of brain tumors at different development and growth stages, we propose the concept of ‘whole-process targeting’ for brain tumor for nano-drug delivery systems, referring to a series of overall targeted drug delivery strategies aimed at key points during the whole development of brain tumors.     

Recent advances of siRNA delivery by nanoparticles

Introduction: The field of RNA interference technology has been researched extensively in recent years. However, the development of clinically suitable, safe and effective drug delivery vehicles is still required.

Areas covered: This paper reviews the recent advances of non-viral delivery of small interfering RNA (siRNA) by nanoparticles, including biodegradable nanoparticles, liposomes, polyplex, lipoplex and dendrimers. The characteristics, composition, preparation, applications and advantages of different nanoparticle delivery strategies are also discussed in detail, along with the recent progress of non-viral nanoparticle carrier systems for siRNA delivery in preclinical and clinical studies.

Expert opinion: Non-viral carrier systems, especially nanoparticles, have been investigated extensively for siRNA delivery, and may be utilized in clinical applications in the future. So far, a few preliminary clinical trials of nanoparticles have produced promising results. However, further research is still required to pave the way to successful clinical applications. The most important issues that need to be focused on include encapsulation efficiency, formulation stability of siRNA, degradation in circulation, endosomal escape and delivery efficiency, targeting, toxicity and off-target effects. Pharmacology and pharmacokinetic studies also present another great challenge for nanoparticle delivery systems, owing to the unique nature of siRNA oligonucleotides compared with small molecules.