Magnetite synthesis in biomimietic nanovesicles: innovative synthetic routes to tailored bio-nanomagnets

近年来，对纳米技术的科学和经济兴趣不断增长。在这方面，寻求生产微小和高度定制的磁性颗粒或纳米磁体至关重要。纳米磁体具有一系列实际用途。从历史上看，它们已被用于信息存储，如磁带和硬盘驱动器。最近，这随着提供高密度数据存储的3D信息存储系统的发展而扩展。纳米磁体的医学应用引起了人们的极大兴趣。正在开发磁性颗粒以在体内提供靶向药物。例如，如果药物在分子水平上与纳米磁体结合，那么它们可以被磁体引导到患者体内的特定部位。这允许药物被递送到特定区域，而不会伤害身体的其他部分。类似地，纳米磁体可用于热疗。这是在被引导到特定肿瘤部位后，磁性颗粒被加热以摧毁肿瘤或激活药物的地方。这种颗粒也已经被用作诊断医学的图像增强剂。然而，随着纳米技术的发展，开发精确设计的纳米磁体的需求也在增长。不同的应用需要不同形状和尺寸的颗粒以及不同的磁性。因此，生产具有高度控制的纳米磁体;成分，尺寸和形状，足够大的量用于这些行业，已成为研究人员的关键目标。生物矿化是发生在活生物体中产生矿物质（如骨骼）的过程。由于遗传学控制生物矿化过程，所产生的材料表现出非常精确，均匀和复杂的结构，直到纳米级。趋磁细菌在细菌细胞内的称为磁小体的生物壳（或囊泡）内生物矿化高质量均匀的氧化铁磁铁矿纳米颗粒。由于磁小体表现出相当大的均匀性和精确性，它们为生产高质量的纳米颗粒提供了一种新颖而有吸引力的途径。然而，生物矿化方法对于商业生产产生低效的产量，并且也不是很灵活，因为细胞严格控制形态和组成，所以粒子不能轻易适应（例如，最大钴掺杂1.4%）。为了合成精确定制的磁性纳米颗粒，我们将探索一种仿生方法，我们从自然界中获得灵感，在细胞外的人工磁小体囊泡内开发纳米磁铁矿沉淀系统。我们将在纳米囊泡内进行简单的环境温度化学沉淀，以帮助控制颗粒大小，并将生物矿化蛋白质掺入囊泡内部，以进一步在颗粒上施加生物学上精确的形态。该系统将联合收割机结合生物矿化的所有优点，例如形态精确性和生物相容性涂层，以及化学沉淀的所有优点，例如高产率和相对于变化更具延展性的系统，此外，这种形成技术使用环境友好的条件，并且向颗粒添加生物相容性脂质涂层对于医疗保健也是非常有利的。应用.

Scientific and economic interest in nanotechnology has grown in recent years. Within this the quest to produce tiny and highly tailored magnetic particles, or nanomagnets is crucial. Nanomagnets have a range of practical uses. Historically they have been used for information storage such as tapes and hard drives. Recently this has expanded with the development of 3D information storage systems providing high density data storage. There is much interest in the medical applications of nanomagnets. Magnetic particles are being developed to provide targeted medicine within the body. For example, if drugs are tied to nanomagnets at the molecular level then they can be directed by a magnet to specific sites within the patient. This allows a drug to be delivered to a specific area, without harming the rest of the body. Similarly, nanomagnets can be used in hyperthermic therapies. This is where, after being directed to specific tumour sites, magnetic particles are heated to either destroy a tumour or activate a drug. Such particles also already have used as image enhancers for diagnostic medicine. However, as nanotechnology grows, so too does the need to develop precisely engineered nanomagnets. Different applications demand different shapes and sizes of particles and different magnetic properties. Producing nanomagnets with highly controlled; composition, size and shapes, in large enough amounts to be of use to these industries, has therefore become a key goal of researchers.Biomineralisation is the process that occurs in living organisms to produce minerals such as bones. Because genetics control biomineralisation processes the materials produced exhibit very precise, uniform and intricate formations down to the nanoscale. Magnetotactic bacteria biomineralise high quality uniform nanoparticles of the iron-oxide magnetite within biological shells (or vesicles) called magnetosomes, within the bacterial cell. Because magnetosomes exhibit considerable uniformity and precision they present a novel and attractive route to produce high quality nanoparticles.However, the biomineralisation method produces inefficient yields for commercial production and is also not very flexible, as the cell strictly controls morphology and composition, so the particles cannot be easily adapted (e.g. maximum cobalt doping 1.4%).In order to synthesise precision customised magnetic nanoparticles, we will explore a biomimetic approach where we take inspiration from nature to develop a nano-magnetite precipitation system within artificial magnetosome vesicles outside the cell. We will perform a simple ambient temperature chemical precipitation of magnetite within nano-vesicles to help control the particle size and incorporate biomineralisation proteins into the interior of the vesicles to further impose biologically precise morphology over the particles. The system will combine all the benefits of biomineralisation such as morphological precision and a biocompatible coating, with all the benefits of a chemical precipitation such as high yields and a more malleable system with respect to variation, so particles can be customised.Additionally this formation technique uses environmentally friendly conditions and the addition of a biocompatible lipid coating to the particles is also highly advantageous for healthcare applications.