Electrosprayed Core-Shell Microparticles as a Pulsatile Vaccine Delivery Platform

项目概要/摘要 每年估计有1940万儿童没有得到世界卫生组织推荐的疫苗。 1.2大多数接种疫苗不足的儿童 生活在低收入和中等收入国家，获得医疗保健的机会往往有限。 儿童至少接种了一剂疫苗，但由于没有完成全部接种， 方案4，5一种疫苗接种方法，在单次注射中递送所有剂量的疫苗或多种疫苗 即使是一次性获得医疗保健的儿童也能得到充分保护， 传染病不幸的是，大多数控释药物递送系统表现出连续释放 动力学，这与在一个周期内以多个离散剂量施用的传统可溶性疫苗有很大不同。 几个月的过程。最近的一项研究描述了生物可降解微粒平台的发展， 一种聚合物壳，包封一个装载疫苗的核心，在一段时间后表现出延迟的脉冲式释放， 通过聚合物降解速率确定。6通过向患者注射混合颗粒群， 不同的降解速率，疫苗可以作为离散脉冲释放，从而模仿传统的疫苗接种 已知安全有效的时间表。不幸的是，原始微粒生产方法不利地 影响抗原稳定性，需要使用大规格针，并且是低通量的。本项目谋求 通过使用同轴电喷雾制备微粒克服了这些挑战， 该方法可以产生被聚合物壳包围的单一含水的装载疫苗的核。这项建议 第一个目的是产生具有致密聚合物壳的小的核-壳微粒， 大分子在体外和体内的脉冲释放。标记的蛋白质将被用作模型 研究颗粒大小、壳密度、相对壁厚和后处理对释放的影响 动力学在确定实现脉冲释放的制剂后，我们将优化加工条件 以使包封的抗原稳定性最大化。将酶报告基因和pH敏感染料添加到该聚合物中。 在颗粒生命周期的几个阶段进行测试，以监测 制造、储存和释放。将调整电喷涂材料和参数，以尽量减少变化 蛋白质构象可能是由溶剂相互作用、热不稳定性和颗粒酸化引起的， 这可能会影响免疫系统产生中和抗体的能力。虽然进一步优化将 该项目将提供一个框架， 开发控释疫苗制剂。最终，这些粒子可以作为一个关键工具， 在资源有限的发展中国家和发达国家， 在世界上，没有保险的儿童和农村社区的疫苗接种覆盖率一直较低。

PROJECT SUMMARY/ABSTRACT Every year an estimated 19.4 million children do not receive the set of vaccines recommended by the World Health Organization, leading to 1.5 million vaccine-preventable deaths.1,2 A majority of undervaccinated children live in low- and middle-income countries and often have limited access to healthcare.2,3 Nearly 6 million of these children receive at least one vaccine dose, but remain at risk because they have not completed the full dosing regimen.4,5 A vaccination method that delivers all doses of a vaccine, or multiple vaccines, in a single injection would enable children with even one-time access to healthcare to be fully protected from the corresponding infectious disease. Unfortunately, most controlled-release drug delivery systems exhibit continuous release kinetics, which is vastly different from traditional soluble vaccines administered in multiple discrete doses over a course of months. One recent study has described the development of biodegradable microparticle platform with a polymer shell encapsulating a vaccine-loaded core that exhibits delayed, pulsatile release after a period determined by the polymer degradation rate.6 By injecting patients with a mixed population of particles with different degradation rates, vaccine can be released as discrete pulses, thereby mimicking traditional vaccination schedules known to be safe and effective. Unfortunately, the original microparticle production method negatively affects antigen stability, requires the use of large-gauge needles, and is low-throughput. This project seeks to overcome these challenges by preparing microparticles using coaxial electrospraying, a single-step fabrication process that can produce a single aqueous, vaccine-loaded core surrounded by a shell of polymer. This proposal first aims to create small core-shell microparticles with dense polymeric shells that demonstrate the delayed, pulsatile release of macromolecules in vitro and in vivo. Fluorescently tagged proteins will be used as model vaccines to study the effects of particle size, shell density, relative wall thickness, and post-processing on release kinetics. After identifying formulations that achieve pulsatile release, we will then optimize processing conditions to maximize encapsulated antigen stability. An enzymatic reporter and a pH-sensitive dye will be added to the core and tested at several stages of the particle life cycle to monitor microenvironmental conditions during fabrication, storage, and release. Electrospraying materials and parameters will be adjusted to minimize changes to protein conformation that could result from solvent interactions, thermal instability, and particle acidification, which may affect the immune system's ability to create neutralizing antibodies. Although further optimization will be required to fine-tune conditions for specific vaccines, this project will provide a framework for quickly developing controlled-release vaccine formulations. Ultimately, these particles could serve as a key tool in the fight against infectious disease both in the developing world where resources are limited and in the developed world, where uninsured children and rural communities show consistently lower vaccination coverage.7