Hybrid Lipid - Inorganic nanoparticles for drug delivery to the brain

药物输送到大脑是具有挑战性的，并且依赖于穿过被称为血脑屏障（BBB）的半透膜。血脑屏障是一种内皮细胞单层，它将血液与大脑中枢神经系统（CNS）分开。当静脉给药时，血脑屏障中的这种紧密连接对大多数药物从血液到中枢神经系统的渗透性提出了物理障碍。氧化应激在帕金森病、肌萎缩性侧索硬化症（ALS）、阿尔茨海默病和中风等多种神经退行性疾病的病理过程中起着重要作用。某些无机纳米颗粒（NPs）是强大的抗氧化剂，具有强大的活性，最近的研究表明，它们是神经退行性疾病的新疗法的有希望的候选者，这些疾病涉及氧化应激，可以中和几种重要的病理性活性氧，这些活性氧可以导致神经退行性疾病。虽然它们显示出巨大的治疗前景，但它们的小尺寸（3-4纳米）意味着它们会迅速从体内清除，积聚在肝脏和脾脏，无法到达大脑，并表现出脱靶毒性。脂质纳米颗粒（LNPs）是一种很有前途的无创策略，可以保护药物的有效载荷和毒性，并已被用作治疗许多疾病（如癌症）的递送载体，最近还用于两种COVID疫苗配方。它们可以增强对大脑的渗透，尽管它们表现出优越的性能，但研究数量有限。LNPs与目前的纳米制剂相比具有优势，包括由于其高内表面积、简单的制备方案、优越的偶联性、可生物降解性/生物相容性以及封装疏水和亲水货物的能力而具有有利的药物有效载荷。这个项目的目的是创造胶体稳定的软物质配方，将无机纳米粒子封装到我们实验室开发的各种新型纳米粒子（100-200纳米）中。这些杂化脂质-无机NPs将通过动态光散射、小角x射线散射、低温透射电镜和长期稳定性研究来表征。无机NPs的包封和释放将用光谱法进行评估。纳米药物配方中固有的异质性可能导致影响产品整体功能的一系列行为和特性。我们将通过不对称流场流分选（AF4）研究这些软物质配方的异质性，根据LNPs的大小和形状将其划分为不同的亚群，这些亚群的特征是在线多角度光散射、UV-Vis光谱和动态光散射。分离的LNP亚群也将离线表征，以阐明药物装载和释放的异质性，这对性能至关重要。

Drug delivery to the brain is challenging and relies on crossing a semipermeable membrane known as the blood-brain barrier (BBB). The BBB is an endothelial cell monolayer that separates the blood from the cerebral central nervous system (CNS). This tight junction in the BBB presents a physical barrier to the permeability of the majority of drugs from the blood to the CNS when administered intravenously. Oxidative stress plays a significant role in the pathology of multiple neurodegenerative diseases such as Parkinson's disease, amyotrophic lateral sclerosis (ALS), Alzheimer's disease and stroke. Certain inorganic nanoparticles (NPs) are powerful antioxidants with robust activity and it was recently shown that they are promising candidates for novel therapy of neurodegenerative diseases involving oxidative stress that can neutralize several important pathological reactive oxygen species that can lead to neurodegeneration. Whilst they show great therapeutic promise, their small size (3-4 nm) means they are rapidly cleared from the body, accumulate in the liver and spleen, are unable to reach the brain and show off-target toxicity. Lipid nanoparticles (LNPs) are a promising noninvasive strategy to protect drug payload and toxicity, and have been employed as delivery vehicles to treat many diseases such as cancer and recently in two COVID vaccine formulations. They can enhance penetration into the brain and although they show superior performance there are limited number of studies. LNPs offer advantages over current nanoformulations, including favourable drug payloads due to their high internal surface area, simple preparation protocols, superior ease of conjugation, biodegradability/ biocompatibility, and the ability to encapsulate hydrophobic and hydrophilic cargo. The aim of this project is to create colloidally stable soft matter formulations that encapsulate inorganic NPs into various novel LNPs (100-200 nm) developed in our labs. These hybrid lipidinorganic NPs will be characterized using Dynamic Light Scattering, Small Angle X-ray Scattering and cryo-TEM and long term stability studies. Encapsulation and release of the inorganic NPs will be assessed spectroscopically. The inherent heterogeneity within a nanomedicine formulation can lead to a range of behaviours and properties that influence the overall functionality of the product. We will investigate the heterogeneity of these soft matter formulations by asymmetric flow field flow fractionation (AF4) to separate LNPs into distinct subpopulations based on their size and shape, which are characterised by in-line multi-angle light scattering, UV-Vis spectroscopy and dynamic light scattering. The fractionated LNP subpopulations will also be characterized off-line to elucidate heterogeneities in drug-loading and release, which is crucial for performance.