肿瘤微环境响应药物递送系统的设计

化学药物治疗(化疗)是目前临床上治疗肿瘤最有效的方法之一,但传统的给药方式导致药物对肿瘤的靶向性差、药物利用率低.在杀伤肿瘤细胞的同时,化疗药物对人体正常细胞也有很大的损伤,因此在化疗过程中通常伴随着严重的副作用,例如恶心、呕吐以及脱发等.随着肿瘤学和纳米材料的迅速发展,多种纳米药物载体被应用于肿瘤的治疗.纳米药物载体...     

基于靶向调控肿瘤微环境的多肽纳米药物系统研究进展

肿瘤微环境在肿瘤的发生、发展和转移过程中起着至关重要的作用,因此靶向调控微环境为发展肿瘤精准治疗的新策略提供了机遇。纳米技术的快速发展为传统药物的增效减毒提供了契机,已有一系列纳米药物用于肿瘤临床治疗。近年来,分子自组装领域的快速发展为智能纳米药物的研发提供了新机遇。多肽作为生物相容性高、序列可设计、易修饰、功能多样化的生物分子,可组装构建结构多样和功能集成的纳米药物系统。本文综述了利用多肽自组装超分子体系实现药物对肿瘤微环境的响应释放和高效递送,并对其通过调控微环境中的血管、成纤维细胞和胞外基质等组分,改变肿瘤赖以生存的"土壤",并与抗肿瘤细胞治疗有机结合的最新进展进行了介绍。针对肿瘤异质性和复杂性的难题,构建表/界面性质可控的纳米药物系统,发展基于肿瘤微环境调控与联合治疗的肿瘤综合治疗方案,将是未来重要的发展方向之一。     

高分子材料调控肿瘤免疫微环境的研究进展

随着肿瘤免疫疗法在临床应用取得巨大突破,通过抗肿瘤免疫反应提高抗肿瘤疗效的治疗方式受到了广泛的关注.然而,肿瘤组织存在复杂的免疫抑制性微环境,严重限制了部分免疫疗法的效果.长期以来,高分子材料作为重要的药物递送载体受到广泛关注,但是其在调控肿瘤免疫微环境的功能及应用方面尚未引起足够的重视.在本文中,我们一方面介绍了肿瘤组织形成免疫抑制性微环境的成因,如肿瘤组织存在多种免疫抑制性细胞,如调节性T细胞(Tregs)、髓系来源抑制性细胞(MDSCs)和肿瘤相关巨噬细胞(TAMs)等,以及免疫细胞、肿瘤细胞等分泌的大量细胞因子、趋化因子、代谢产物等.另一方面,重点介绍了近年来高分子材料作为载体递送免疫调节分子或发挥自身免疫调节功能,调控或逆转免疫抑制性微环境的策略和典型代表,证明了高分子材料在调控肿瘤免疫微环境,改善肿瘤治疗效果方面的巨大潜力.     

肿瘤微环境刺激响应型上转换光动力诊疗体系的构建和发展

光动力治疗是一种新型的非侵入式肿瘤治疗方法,具有创伤性和毒性小、选择性好、无耐药性、可重复治疗等突出优点,在癌症的治疗上取得了显著的成效.为了增加光动力治疗的组织穿透深度,研究者提出构建基于上转换纳米颗粒(upconversion nanoparticles, UCNPs)的光动力诊疗探针(简称上转换光动力诊疗探针).基于发光共振能量转移过程,上转换光动力诊疗探针利用UCNPs在近红外光激发下发射的荧光激活负载的光敏剂发挥光动力疗效,有助于实现深层肿瘤的治疗.新型的上转换光动力诊疗探针通过多功能一体化的结构组合设计可以实现靶向运输、成像诊断以及刺激响应的按需治疗,是未来纳米医药发展的必然趋势.目前,研究者越来越关注构建基于肿瘤微环境刺激响应型上转换光动力诊疗体系,以提高治疗体系的靶向性,改善光动力治疗效果,并减小对周围正常组织的毒性.本工作主要讨论了基于pH、酶及过氧化氢刺激响应型上转换光动力诊疗体系的构建和发展,并对其发展前景进行了展望.     

多肽介导的肿瘤靶向纳米递药系统

肿瘤靶向纳米递药系统是指利用肿瘤组织特殊的生理病理特点,由纳米载体包载肿瘤诊疗药物构建而成的对肿瘤组织具有靶向定位功能的药物递送系统。多肽介导的肿瘤靶向纳米递药系统是肿瘤靶向递药领域较新的一个研究方向,本文综述了该研究方向的四个重要发展历程——单功能靶向、双功能靶向、肿瘤穿透和环境响应型靶向纳米递药系统,并介绍了各类递药系统的设计原理和典型研究案例。此外,对目前多肽介导的纳米递药系统存在的优势与不足进行了分析。最后,针对当前主动靶向肿瘤递药系统存在的研究困境,提出了一种新型肿瘤靶向递药策略——"系统性靶向"策略。随着相关学科和多学科交叉的发展,多肽介导的肿瘤靶向纳米递药系统将在肿瘤治疗中扮演更为重要的角色。     

基于cypate光裂解的新型近红外光响应稀土上转换纳米载药系统※

光响应药物释放体系具有非侵入性、远程可控且时空分辨率高等特点, 在杀菌、抗癌等生物医学领域具有重要应用价值. 但目前近红外光响应的光裂解药物递送体系报道较少且光响应效率还有待提高. 本工作将稀土纳米颗粒包覆介孔二氧化硅, 逐步偶联近红外染料cypate、金刚烷胺和β-环糊精来封堵孔口, 利用cypate的自敏光氧化断键作为光响应开关, 成功构建了一种新型近红外光响应稀土上转换纳米载药系统. 该纳米载药系统负载抗生素氧氟沙星表现出极低的药物流失率和较高的808 nm光照释放效率, 并且通过控制光照时间可以满足不同的给药量需求. 体外抗菌实验结果进一步验证了该纳米载药系统的光响应药物释放性能. 此外, 该纳米载药系统在980 nm激光激发下的上转换发光较强且不影响药物释放, 可以实现纳米载药系统的药物定位和生物成像功能. 本研究为发展高效光响应载药体系提供了新的思路.     

外泌体递药系统及其在肿瘤治疗中的应用

癌症是世界上第二大死亡原因,其每年的发病率都很高。尽管现有的治疗方法在过去十年中取得了重大进展。但是由于现有多数抗肿瘤药物具有非特异性细胞毒性、生物相容性差和生物利用度低等缺点,导致化疗等方法的治疗效果较差。外泌体是由多种细胞分泌的囊泡,具有磷脂双层结构和纳米颗粒大小。它具有良好的生物相容性、高稳定性和良好的靶向性。在癌症治疗中,外泌体作为一种潜在有效的药物递送系统已经引起越来越多的关注。本文综述了外泌体作为靶向肿瘤药物载体的设计策略,并试图为基于外泌体的纳米载体在各种肿瘤治疗中的应用提供新的见解。     

刺激响应性聚合物载药纳米胶束研究进展

刺激响应性聚合物纳米胶束是目前药物控制释放体系的研究热点之一,其原理是将疏水性药物以物理或化学方法包覆在具有核/壳结构的纳米微球中,通过环境刺激响应控制药物的包覆与释放,可增加疏水性药物溶解度、提高药物利用率、降低药物毒副作用,具有显著的研究价值和应用前景.本文中我们主要介绍了不同类型刺激响应性聚合物纳米胶束在药物控制释放体系的研究进展.     

靶向肿瘤进化的创新纳米药物

近年来,随着纳米技术的发展,将纳米材料应用于肿瘤靶向治疗有望极大地改善肿瘤治疗效果.纳米药物因其可增加药物溶解性、延长血液循环时间、提高靶向性、提升治疗效果并降低毒副作用等特点而备受研究者关注.肿瘤生物学研究表明,肿瘤始终处于动态的进化和演化过程之中,由于其基因组的不稳定性,肿瘤细胞可在肿瘤内部的生存压力下进行自然选择,或在外来治疗压力(放射治疗、化学治疗、分子靶向治疗和免疫治疗)作用下,持续产生基因突变并扩增,从而导致肿瘤增殖、耐药和转移.因此,肿瘤治疗方案理应随着肿瘤的进化过程而变化和调整.然而,现阶段纳米药物的设计对肿瘤进化的临床现实缺乏充分考虑.本文提出靶向肿瘤进化的创新纳米药物的构想,即从肿瘤进化的临床现实出发,尽可能灵敏地、准确地、全面地跟踪肿瘤在自然选择、治疗压力下出现的增殖、耐药、转移等过程,掌握该过程中的进化特征,并基于这些进化特征设计创新纳米药物,能够有策略地、主动地、及时地动态调整纳米药物及给药方案,结合临床上其他多种治疗药物和方法,力争把肿瘤控制为慢性疾病.     

刺激响应聚合物微针在经皮给药中的应用

聚合物微针自身具有良好的机械性能和优异的生物相容性,能以微创的方式刺穿皮肤角质层,实现药物的高效经皮吸收,从而有效治疗各种疾病,如糖尿病、癌症、肥胖以及眼部疾病等.如何调控聚合物微针中负载药物的释放行为,是微针经皮给药需要关注的核心要素.刺激响应释放聚合物微针作为一种新兴的按需给药技术,能根据外界环境条件或自身生理环境...     

Construction of Smart Stimuli-Responsive DNA Nanostructures for Biomedical Applications

DNA nanostructures have recently attracted increasing interest in biological and biomedical applications by virtue of their unique properties, such as structural programmability, multi-functionality, stimuli-responsive behaviors, and excellent biocompatibility. In particular, the intelligent responsiveness of smart DNA nanostructures to specific stimuli has facilitated their extensive development in the field of high-performance biosensing and controllable drug delivery. This minireview begins with different self-assembly strategies for the construction of various DNA nanostructures, followed by the introduction of a variety of stimuli-responsive functional DNA nanostructures for assembling metastable soft materials and for facilitating amplified biosensing. The recent achievements of smart DNA nanostructures for controllable drug delivery are highlighted. Finally, the current challenges and possible developments of this promising research are discussed in the fields of intelligent nanomedicine.     

Stimuli-Responsive Delivery of Antimicrobial Peptides Using Polyelectrolyte Complexes

Antimicrobial peptides (AMPs) are antibiotics with the potential to address antimicrobial resistance. However, their translation to the clinic is hampered by issues such as off-target toxicity and low stability in biological media. Stimuli-responsive delivery from polyelectrolyte complexes offers a simple avenue to address these limitations, wherein delivery is triggered by changes occurring during microbial infection. The review first provides an overview of pH-responsive delivery, which exploits the intrinsic pH-responsive nature of polyelectrolytes as a mechanism to deliver these antimicrobials. The examples included illustrate the challenges faced when developing these systems, in particular balancing antimicrobial efficacy and stability, and the potential of this approach to prepare switchable surfaces or nanoparticles for intracellular delivery. The review subsequently highlights the use of other stimuli associated with microbial infection, such as the expression of degrading enzymes or changes in temperature. Polyelectrolyte complexes with dual stimuli-response based on pH and temperature are also discussed. Finally, the review presents a summary and an outlook of the challenges and opportunities faced by this field. This review is expected to encourage researchers to develop stimuli-responsive polyelectrolyte complexes that increase the stability of AMPs while providing targeted delivery, and thereby facilitate the translation of these antimicrobials.     

DNA Nanostructures as Drug Carriers for Cellular Delivery

Drug delivery systems have been widely developed for enhancing target activity and improving drug functions.Liposomes,high-molecular polymer,gold nanoparticles and carbon nanomaterials,etc.,are all the candidates of drug carriers.However,immunotoxicity,heterogeneity and low solubility generally exist and hamper their applications.As a kind of biological materials,DNA has its unique advantages in biomedical applications,including excellent biological compatibility and programmability.DNA nanostructures have been proved to possess high cellular uptake efficiency,which sheds new light on DNA-based drug delivery system.In this review,we summarize the influence factors of DNA nanostructure internalization efficiency,including cell lines,and the size and the shape of DNA nanoparticles.Uniformity of DNA nanostructures in appearance and properties ensures the stability in research,which makes DNA carriers stand out from other nanomaterials.Next,we focus on the functionalization of DNA carriers,which endows DNA nanostructures with the potential to construct integrated drug delivery platforms.We also discuss the internalization pathways of DNA nanostructures and their fate in cells.The deeply understanding about the endocytic pathways provides new sight for the further design strategy on changing the transportation routes of DNA carriers in cells.Finally,the challenges in further applications are discussed,and suggestions are proposed.     

Pillararene-Based Supramolecular Vesicles for Stimuli-Responsive Drug Delivery

Supramolecular vesicles (SMVs) self-assembled from the supra-amphiphiles, consisting of two scaffolds linked together through noncovalent interactions, can realize stimuli-responsive controlled release of encapsulated drugs for enhanced therapeutic efficacy and minimized side effect of drugs. Pillararenes (PAs), an emerging kind of macrocyclic hosts in 2008, are easy to modify with a variety of functionalities. SMVs from PAs and specific guests mainly based on the host–guest interactions have attracted increasing attention because of their drug delivery and controlled drug release. A great progress in the construction and stimuli-responsive drug delivery of the PA-based SMVs has been made since the first work was reported in 2012. This review summarizes the major achievements of the PA-based SMVs for stimuli-responsive drug delivery over the past 5 years, including the microstructures of SMVs, multiple stimuli-responsive SMVs, prodrug SMVs from prodrug PAs and guests, bola-type SMVs, multifunctional SMVs, glucose-responsive SMVs for insulin delivery, novel SMVs from responsive PAs, thermo-responsive SMVs, and ternary SMVs, for chemotherapy, photothermal therapy, photodynamic therapy, and other biological applications. The future challenges and research directions of PA-based SMVs are also outlined from the points of views of the fundamental research, biological applications, and clinical applications of PA-based SMVs.     

基于环糊精的智能刺激响应型药物载体

智能药物载体凭借其独特的刺激-响应机制控制药物的释放速度和转运部位,已成为当前化学与药学领域的研究热点之一。由于具有提高药物在体内的生物利用度和降低其毒副作用等优点,智能药物载体将在未来的临床治疗中起到越来越重要的作用。近年来,环糊精作为药物载体材料的研究取得了巨大进步,其在药物控释的时间、空间和剂量上更为准确。环糊精具有大环结构,可自组装、易于功能化、天然无毒且价格低廉,已被广泛应用于构筑智能药物载体。凭借其自组装、分子识别和动态可逆性能力,环糊精可以同其他生物相容性材料构筑具有不同性能的智能药物载体。这种载体可在外界刺激下做出相关理化性质改变的反馈调节,包括通过内源性刺激(pH值、氧化还原物质和酶浓度等)和外源性刺激(温度、光、磁场、超声和电压等),进而控制药物的释放。本文综述了面向不同刺激因素的基于环糊精智能刺激响应型药物载体的作用机理、特点和应用的最新研究进展,并对其发展前景作了进一步的展望。     

Multifunctional DNA Origami Nanoplatforms for Drug Delivery

DNA nanotechnology has been employed in the construction of self‐assembled nano‐biomaterials with uniform size and shape for various biological applications, such as bioimaging, diagnosis, or therapeutics. Herein, recent successful efforts to utilize multifunctional DNA origami nanoplatforms as drug‐delivery vehicles are reviewed. Diagnostic and therapeutic strategies based on gold nanorods, chemotherapeutic drugs, cytosine–phosphate–guanine, functional proteins, gene drugs, and their combinations for optoacoustic imaging, photothermal therapy, chemotherapy, immunological therapy, gene therapy, and coagulation‐based therapy are summarized. The challenges and opportunities for DNA‐based nanocarriers for biological applications are also discussed.     

Multivalent Aptamer-modified DNA Origami as Drug Delivery System for Targeted Cancer Therapy

In spite of great development in nanoparticle-based drug delivery systems(DDSs)for improved therapeutic efficacy,it remains challenging for effective delivery of chemotherapeutic drugs to targeted tumor cells.In this work,we report a triangle DNA origami as targeted DDS for cancer therapy.DNA origami shows excellent biocompatibility and stability in cell culture medium for 24 h.In addition,the DNA origami structures conjugated with multivalent aptamers enable for efficient delivery of anticancer drug doxorubicin(Dox)into targeted cancer cell due to their targeting function,reducing side effects associated with nonspecific distribution.Moreover,we also demonstrated that the multivalent aptamer-modified DNA origami loading Dox exhibits prominent therapeutic efficacy in vitro.Accordingly,this work provides a good paradigm for the development of DNA origami nanostructure-based targeted DDS for cancer therapy.     

双刺激响应型纳米载药系统的构建及性能

采用聚乙二醇单甲醚(mPEG)为亲水段,聚赖氨酸(PzLL)为疏水段,通过二硫键和碳氮双键串联桥连合成了两嵌段共聚物(mPEG-CN-SS-PzLL),其中的二硫键具有还原敏感性,碳氮双键具有pH酸敏感性。通过红外光谱和核磁共振谱等手段测试分析了产物的化学结构。将聚合物通过透析法自组装制备得到双刺激响应型纳米载药粒子。结果表明:该纳米载药粒子的药物包封率较高,达到52%。该载药系统在还原环境或酸性环境下具有良好的体外释药性能。