壳聚糖衍生物在口鼻黏膜疫苗中的应用

壳聚糖是一种有效的黏膜疫苗佐剂和递送载体,但因其水溶性差,应用受到一定限制.通过对壳聚糖进行不同的化学修饰可得到各类壳聚糖衍生物,这些衍生物不仅溶解性较好,而且保持了壳聚糖良好的生物相容性、生物降解性、免疫刺激活性等优势,为黏膜疫苗,尤其是经口、鼻途径递送的疫苗提供了新型候选佐剂和递送载体.此文对修饰壳聚糖的主要方法以及其衍生物在口鼻黏膜疫苗中的应用做一综述.     

纳米疫苗的发展与应用

传统疫苗在传染病防治领域发挥了重要作用,但其仍不同程度地存在安全性差、免疫原性低、稳定性差、难以诱导持久免疫反应等问题。纳米递送系统可提高抗原稳定性并靶向抗原提呈细胞,促进抗原提呈细胞成熟并激活特异性免疫反应。目前已有大量研究利用纳米递送载体制备高效疫苗。该文简要阐述纳米递送载体在增强疫苗免疫效应中的应用。     

红细胞作为药物递送系统的研究进展

传统的治疗药物存在稳定性差、摄取效率低、细胞毒性大以及靶向能力差等缺点。因此需要安全的药物传递系统来延长药物在体内的循环和暴露。以红细胞为载体的新型药物递送系统凭借其良好的生物相容性、低免疫原性以及长循环时间而逐渐成为理想的药物递送平台。基于红细胞的药物递送系统包括多种类型,主要有红细胞膜包裹纳米颗粒载药系统和基因工程红细胞等。另外,对红细胞进行功能化修饰,可显著增强靶向性,进一步开发和扩大红细胞载药体系在多种疾病治疗中的应用。本研究介绍了以红细胞为载体的化学药物及疫苗的递送方法,重点讨论了仿生纳米红细胞药物递送系统及其对机体各部位的靶向性研究,并且总结了近年来基因工程红细胞策略的研究进展。     

细胞膜仿生纳米载体的制备及应用研究进展

由有机或无机纳米材料制备的药物载体系统广泛用于药物靶向递送和疾病的诊断治疗研究。但其存在靶向性差、体内循环时间短、生物相容性欠佳亟需提高等问题。仿生纳米药物系统是以不同种类的细胞膜修饰纳米载体,利用内源性的细胞膜提高载体的体内生物相容性、实现更精准的靶向、甚至由细胞自身的免疫原性产生免疫治疗作用。对细胞膜仿生纳米载体技术的原理、方法及其靶向机制和治疗作用作一综述,为新型给药系统研究提供思路。     

壳聚糖及其衍生物纳米粒的制备以及在疫苗中的应用

壳聚糖是一种高分子线性阳离子多糖。由壳聚糖及其化学改性衍生物制备的纳米粒具有生物相容性好、细胞毒性低以及可降解等特点,人们对其作为佐剂或递送系统在疫苗中的应用已开展了广泛研究。此文对壳聚糖及其衍生物纳米粒的制备方法以及在疫苗中的应用进行综述。     

叶酸修饰壳聚糖在肿瘤靶向制剂中的研究进展

壳聚糖及其衍生物具有无毒、生物可降解性和良好的生物相容性等特点,在药物递送系统中有良好的应用前景。叶酸受体在肿瘤细胞过表达,利用叶酸与其受体的特异性结合,可实现靶向肿瘤效应。该文综述叶酸修饰壳聚糖及其在肿瘤靶向制剂方面的研究。     

壳聚糖及其衍生物在药物递送中的研究进展

壳聚糖是自然界中存在的唯一的带正电的碱性氨基多糖,具有来源丰富、无毒、低免疫原性、良好的生物可降解性和生物相容性等优点。壳聚糖的活性氨基和羟基,经各种化学修饰如羧基化、巯基化、季铵化、疏水修饰、长循环修饰和靶向修饰,可获得具有特殊功能特性的衍生物,广泛用作药物和基因的载体材料。是近年来药剂学领域的研究热点。本文就近年来壳聚糖及其衍生物在药物递送中的研究进展作一综述。     

壳聚糖纳米粒作为药物递送系统在癌症治疗中的应用

癌症是威胁人类生存的恶性疾病之一。近年来,利用纳米技术将药物靶向递送到肿瘤部位,可以增加疗效并降低毒性,为癌症治疗带来了新希望。壳聚糖是自然界唯一存在的碱性多糖,具有良好的生物相容性和生物可降解性。此外,其反应位点多,可制成不同性质的衍生物,广泛用于药物递送系统和组织工程支架,在生物医药领域具有重要的应用价值。本综述对近年来壳聚糖纳米粒在抗癌药物递送方面的研究进展进行介绍,重点介绍了壳聚糖纳米粒的制备、被动靶向、主动靶向和刺激-响应药物递送系统方面的研究进展。     

抗病毒药物新型给药系统的研究进展

由病毒引发的疾病严重危害人类健康,疫苗为人类对抗病毒感染的重要手段,包括治疗性和预防性疫苗.抗病毒药物的新型口服给约系统(如微乳与自微乳化制剂、黏附微球和纳米凝胶)可提高药物的生物利用度,减轻不良反应.通过微针介导的透皮免疫和呼吸道黏膜免疫可望提高机体的免疫应答及使用者的顺应性.本文综述了抗病毒药的新型口服给药系统,及通过微针介导的透皮和呼吸道黏膜递送疫苗的研究进展.     

外泌体在脑靶向递送中的应用

血脑屏障(blood brain barrier, BBB)限制了大部分药物的脑靶向递送,进而影响神经系统疾病有效治疗。外泌体作为细胞衍生的纳米囊泡,可参与物质的细胞间运输、介导细胞间通讯和调节机体生物功能等,具有低免疫原性、低毒性及可天然跨越BBB的优点,在脑靶向递送中发挥重要作用。本文概括了外泌体分类、来源、脑靶向递送机制及其在脑部疾病中发挥的作用,为其临床应用提供参考。     

Formulation design considerations for oral vaccines

Whilst oral vaccination is a potentially preferred route in terms of patient adherence and mass vaccination, the ability to formulate effective oral vaccines remains a challenge. The primary barrier to oral vaccination is effective delivery of the vaccine through the GI tract owing to the many obstacles it presents, including low pH, enzyme degradation and bile-salt solubilization, which can result in breakdown/deactivation of a vaccine. For effective immune responses after oral administration, particulates need to be taken up bythe M cells however, these are few in number. To enhance M-cell uptake, particle characteristics can be optimized with particle size, surface charge, targeting groups and bioadhesive properties all being considerations. Yet improved uptake may not translate into enhanced immune responses and formulating particulates with inherent adjuvant properties can offer advantages. Within this article, we establish the options available for consideration when building effective oral particulate vaccines.     

Chitosan-based delivery systems for mucosal vaccines

Introduction: Mucosal vaccine development faces several challenges and opportunities. Critical issues for effective mucosal vaccination include the antigen-retention period that enables interaction with the lymphatic system, choice of adjuvant that is nontoxic and induces the required immune response and possibly an ability to mimic mucosal pathogens. Chitosan-based delivery systems are reviewed here as they address these issues and hence represent the most promising candidates for the delivery of mucosal vaccines. Areas covered: A comprehensive literature search was conducted, to locate relevant studies published within the last 5 years. Mucosal delivery via nasal and oral routes is evaluated with respect to chitosan type, dosage forms, co-adjuvanting with novel adjuvants and modulation of the immune system. Expert opinion: It is concluded that chitosan derivatives offer advantageous opportunities such as nanoparticle and surface charge manipulation that facilitate vaccine targeting. Nevertheless, these technologies represent a longer-term goal. By contrast, chitosan (unmodified form) with or without a co-adjuvant has significant toxicology and human data to support safe mucosal administration, and thus has the potential for earlier product introduction into the market.     

Nanocarriers Targeting Dendritic Cells for Pulmonary Vaccine Delivery

Pulmonary vaccine delivery has gained significant attention as an alternate route for vaccination without the use of needles. Immunization through the pulmonary route induces both mucosal and systemic immunity, and the delivery of antigens in a dry powder state can overcome some challenges such as cold-chain and availability of medical personnel compared to traditional liquid-based vaccines. Antigens formulated as nanoparticles (NPs) reach the respiratory airways of the lungs providing greater chance of uptake by relevant immune cells. In addition, effective targeting of antigens to the most ‘professional’ antigen presenting cells (APCs), the dendritic cells (DCs) yields an enhanced immune response and the use of an adjuvant further augments the generated immune response thus requiring less antigen/dosage to achieve vaccination. This review discusses the pulmonary delivery of vaccines, methods of preparing NPs for antigen delivery and targeting, the importance of targeting DCs and different techniques involved in formulating dry powders suitable for inhalation.     

Chitosan-based delivery systems for mucosal vaccines

Introduction: Mucosal vaccine development faces several challenges and opportunities. Critical issues for effective mucosal vaccination include the antigen-retention period that enables interaction with the lymphatic system, choice of adjuvant that is nontoxic and induces the required immune response and possibly an ability to mimic mucosal pathogens. Chitosan-based delivery systems are reviewed here as they address these issues and hence represent the most promising candidates for the delivery of mucosal vaccines.

Areas covered: A comprehensive literature search was conducted, to locate relevant studies published within the last 5 years. Mucosal delivery via nasal and oral routes is evaluated with respect to chitosan type, dosage forms, co-adjuvanting with novel adjuvants and modulation of the immune system.

Expert opinion: It is concluded that chitosan derivatives offer advantageous opportunities such as nanoparticle and surface charge manipulation that facilitate vaccine targeting. Nevertheless, these technologies represent a longer-term goal. By contrast, chitosan (unmodified form) with or without a co-adjuvant has significant toxicology and human data to support safe mucosal administration, and thus has the potential for earlier product introduction into the market.     

Nasal vaccine innovation

The current vaccine market is gaining momentum in the development of alternative administration routes namely intranasal, oral, topical, pulmonary, vaginal, and rectal; the nasal route offers the most promising opportunity for vaccine administration. It can enhance convenience, safety, elicit both local and systemic immune responses; thus potentially provide protection from pathogens at the site of entry. Nasal vaccine innovation comes with both opportunities and challenges. The innovative strategies used by industry and researchers to overcome the hurdles are discussed in this article: these include live-attenuated vaccines, adjuvants, mucoadhesives, particulate delivery systems, virus-like particles, vaccine manufacture, challenges of regulatory authorities, and the nasal vaccine impact on market potential. Critical issues for effective nasal vaccination are the antigen-retention period that enables its interaction with the lymphatic system and choice of an adjuvant that is nontoxic and induces the required immune response. Co-adjuvanting by means of a mucoadhesive technology addresses some of these issues. ChiSys^®, a natural bioadhesive with proven intranasal safety profile, has already demonstrated efficacy for several nasally delivered vaccines including norovirus. With the looming threat of a pandemic, alternatives such as intranasal vaccination will ultimately facilitate greater public compliance and rapid mass global vaccination.     

Rational design of nasal vaccines

Nasal vaccination is a promising alternative to classical parental vaccination, as it is non-invasive and, in principle, capable of eliciting strong systemic and local immune responses. However, the protective efficacy of nasally administered antigens is often impaired because of delivery problems: free antigens are readily cleared from the nasal cavity, poorly absorbed by nasal epithelial cells and generally have low intrinsic immunogenicity. In this review paper, we describe the main physiological hurdles to nasal vaccine delivery, survey the progress made in technological approaches to overcome these hurdles and discuss emerging opportunities for improving nasal vaccines. According to current insights, encapsulation of the antigen into bioadhesive (nano)particles is a promising approach towards successful nasal vaccine delivery. These antigen-loaded particles can be tailor made by supplying them with targeting ligands, adjuvants or endosomal escape mediators to form the desired vaccine that provides long-lasting protective immunity.     

Targeting Vaccines to Dendritic Cells

Dendritic cells (DC) are specialized antigen presenting cells (APC) with a remarkable ability to take up antigens and stimulate major histocompatibility complex (MHC)-restricted specific immune responses. Recent discoveries have shown that their role in initiating primary immune responses seems to be far superior to that of B-cells and macrophages. DC are localized at strategic places in the body at sites used by pathogens to enter the organism, and are thereby in an optimal position to capture antigens. In general, vaccination strategies try to mimic the invasiveness of the pathogens. DC are considered to play a central role for the provocation of primary immune responses by vaccination. A rational way of improving the potency and safety of new and already existing vaccines could therefore be to direct vaccines specifically to DC. There is a need for developing multifunctional vaccine drug delivery systems (DDS) with adjuvant effect that target DC directly and induce optimal immune responses. This paper will review the current knowledge of DC physiology as well as the progress in the field of novel vaccination strategies that directly or indirectly aim at targeting DC.     

Drug evaluation: tesamorelin, a synthetic human growth hormone releasing factor

Theratechnologies, under license from Valeant, is developing tesamorelin as a potential vaccine adjuvant and for the potential treatment of wasting, hip fracture recovery, immune disorders, HIV-related lipodystrophy, sleep maintenance insomnia and mild cognitive impairment. Phase III clinical trials for the treatment of HIV-associated lipodystrophy and phase II clinical trials for sleep disorder, chronic obstructive pulmonary disorder, hip fracture and immune system dysfunction are underway. Phase II trials are also assessing the influenza vaccination immune response and cognitive effects of tesamorelin.     

DNA-based vaccination against hepatitis B virus using dissolving microneedle arrays adjuvanted by cationic liposomes and CpG ODN

DNA vaccines are simple to produce and can generate strong cellular and humoral immune response, making them attractive vaccine candidates. However, a major shortcoming of DNA vaccines is their poor immunogenicity when administered intramuscularly. Transcutaneous immunization (TCI) via microneedles is a promising alternative delivery route to enhance the vaccination efficacy. A novel dissolving microneedle array (DMA)-based TCI system loaded with cationic liposomes encapsulated with hepatitis B DNA vaccine and adjuvant CpG ODN was developed and characterized. The pGFP expression in mouse skin using DMA was imaged over time. In vivo immunity tests in mice were performed to observe the capability of DMA to induce immune response after delivery of DNA. The results showed that pGFP could be delivered into skin by DMA and expressed in skin. Further, the amount of expressed GFP was likely to peak at day 4. The immunity tests showed that the DMA-based DNA vaccination could induce effective immune response. CpG ODN significantly improved the immune response and achieved the shift of immune type from predominate Th2 type to a balance Th1/Th2 type. The cationic liposomes could further improve the immunogenicity of DNA vaccine. In conclusion, the novel DMA-based TCI system can effectively deliver hepatitis B DNA vaccine into skin, inducing effective immune response and change the immune type by adjuvant CpG ODN.     

Emerging vaccine nanotechnology: From defense against infection to sniping cancer

Looking retrospectively at the development of humanity, vaccination is an unprecedented medical landmark that saves lives by harnessing the human immune system. During the ongoing coronavirus disease 2019 (COVID-19) pandemic, vaccination is still the most effective defense modality. The successful clinical application of the lipid nanoparticle-based Pfizer/BioNTech and Moderna mRNA COVID-19 vaccines highlights promising future of nanotechnology in vaccine development. Compared with conventional vaccines, nanovaccines are supposed to have advantages in lymph node accumulation, antigen assembly, and antigen presentation; they also have, unique pathogen biomimicry properties because of well-organized combination of multiple immune factors. Beyond infectious diseases, vaccine nanotechnology also exhibits considerable potential for cancer treatment. The ultimate goal of cancer vaccines is to fully mobilize the potency of the immune system as a living therapeutic to recognize tumor antigens and eliminate tumor cells, and nanotechnologies have the requisite properties to realize this goal. In this review, we summarize the recent advances in vaccine nanotechnology from infectious disease prevention to cancer immunotherapy and highlight the different types of materials, mechanisms, administration methods, as well as future perspectives.