Molecularly Imprinted Core-Shell Nanoparticles / understanding fundamentals and developing applications based on biorecognition

生物蛋白，如抗体和一种称为链霉亲和素的细菌蛋白，被广泛用于开发测定大分子（如指示疾病状态的蛋白质，如病毒的存在）和小分子（如药物或杀虫剂）的方法。这种检测方法用于临床诊断、环境监测、法医分析，也用于家庭诊断产品，如妊娠检测试剂盒。虽然这些蛋白质效果很好，但它们通常生产成本很高，而且不太稳定，这限制了产品的保质期，通常意味着它们必须小心储存（例如在冰箱中）。这对产品开发人员来说是一个大问题，特别是如果产品将在第三世界环境中使用。如果这些脆弱的生物分子可以被强大的合成类似物取代，这将是一个巨大的技术突破，这些类似物与抗体具有相同的功能，但生产成本低廉且储存稳定。在过去的几年里，一种被称为“分子印迹”的技术被开发出来，这种技术可以在塑料材料中快速而廉价地生产出具有类似抗体特性的材料。这些“分子印迹聚合物”的制造过程很像分子尺度的石膏铸造。单体（聚合物的构建块）围绕一个分子模板组装，然后聚合成聚合物。一旦聚合物固化，模板就可以被移除，留下一个模压的分子受体，它能够以高精度重新结合模板。MIPs非常坚固，可以在室温下几乎无限期地储存而不会失去功能。目前mip的问题在于，它们通常以大块的形式制成，然后被压碎成微小的颗粒供使用。然而，与蛋白质等生物分子相比，这些颗粒非常大，这导致了在试图使用MIPs进行检测时出现许多问题，例如分子通过MIPs的运输非常缓慢，或者大分子根本无法穿透塑料结构。如果mip能在纳米级（1纳米= 1毫米的百万分之一）/与蛋白质、病毒等类似的尺寸上制造，那就更好了，这样与生物分子的混合就可以非常迅速了。最近，我们的团队已经开发出一种方法来制造如此规模的mip，我们相信这种方法将适用于各种不同性质的不同类型分子的印迹。这种方法包括在聚合物纳米颗粒/所谓的核壳纳米颗粒表面周围的薄壳中制造MIP。这种特殊的形式非常令人兴奋，因为纳米颗粒的核心可以被设计成具有有用的特性，使颗粒更容易被看到（例如，当被特定波长的光照射时，它可能会发出荧光）或操作（例如，它可能是磁性的，因此纳米颗粒可以很容易地从使用磁铁的溶液中提取）。这些性质在设计特定的测定或分析试剂时非常有用。模塑的受体位点将位于或非常靠近纳米颗粒周围非常薄的外壳表面，在那里它们可以很容易地与目标分子相互作用，或者结合到目标分子存在的表面。这个项目的目的是研究这种合成核-壳MIP纳米颗粒的方法是否可以导致新型廉价、强大的仿生试剂，这些试剂可以在分析和诊断测试中用作抗体或其他生物蛋白的替代品。

Biological proteins, such as antibodies and a bacterial protein called streptavidin, are widely used in developing assays to measure both large (e.g. proteins that indicate disease states such as the presence of a virus) and small molecules (e.g. drugs or pesticides). Such assays are used in clinical diagnosis, environmental monitoring, forensic analysis and also in home diagnostic products such as pregnancy test kits. While these proteins work well, they are generally very expensive to produce and are not very stable, which limits the shelf-life of products and often means that they have to be carefully stored (e.g. in a refrigerator). This is a major problem for product developers, particularly if the product will be used in third world environments. It would be a huge technological breakthrough if these fragile biological molecules could be replaced by robust synthetic analogues that had the same function as the antibodies, but were inexpensive to produce and stable in storage. Over the last few years a technique has been developed called 'molecular imprinting', which allows materials with antibody-like properties to be produced quickly and cheaply in plastic materials. These 'molecularly imprinted polymers - MIPs' are made by a process much like molecular scale plaster casting. Monomers (the building blocks of the polymer) are assembled around a molecular template and are then polymerised to make the polymer. Once the polymer is cured, the template can be removed to leave a moulded molecular receptor that is capable of rebinding the template with a high degree of precision. MIPs are extremely robust and can be stored almost indefinitely at room temperature without loss of fuction. The problem with current MIPs is that they are generally made in the form of large blocks, which are then crushed up into tiny particles for use. These particles are very big compared with biological molecules such as proteins, however, and this leads to many problems when trying to use MIPs for developing assays, such as very slow transport of molecules through the MIPs or inability of larger molecules to penetrate into the plastic structure at all. It would be much better if the MIPs could be made at the nano-scale (1 nm = 1 milionth of 1 mm) / a similar size to that of proteins, viruses etc., so that mixing with biological molecules could be very rapid. Recently, our group has developed a method to make MIPs at such a scale, which we believe will be applicable to imprinting of a wide range of different types of molecules with different properties. This method involves creating the MIP in a thin shell around the surface of a polymer nanoparticle / a so-called core-shell nanoparticle. This particular format is very exciting because the core of the nanoparticle can be designed to have useful properties that make the particles easier to see (e.g. it might fluoresce when irradiated with light of a particular wavelength) or manipulate (e.g. it might be magnetic, so that the nanoparticles can be extracted easily from a solution using a magnet). These properties are very useful in the design of particular assays or analytical reagents. The moulded receptor sites would be at or very near to the surface of the very thin shell around the nanoparticle, where they can easily interact with the target molecule or bind to a surface where the target molecule is found. The aim of this project is to investigate whether this approach to synthesising core-shell MIP nanoparticles can lead to new types of cheap, robust bio-mimetic reagents that can be used as substitutes for antibodies or other biological proteins in assays and diagnostic tests.