Enzyme activity is often a key measurement to make in a biological sample

许多疾病状态可以通过特定酶的相对活性来指示，许多药物的目标是上调或下调酶活性。酶现在也被用于工业过程中，不仅用于生物医学，还被合成修饰，用于塑料的降解和回收以及燃料的生产。因此，我们的目标是开发简单、准确的酶活性分析，最终可以(1)多路传输一次检测几种不同的酶，(2)小型化到高通量设备中。这些检测是基于对发光纳米材料(如“量子点”)的表面进行修饰来创建酶传感器。例如，带有末端染料的多肽可以结合到量子点纳米颗粒的表面。染料的荧光是由纳米颗粒的发光激发的(通过共振能量转移)。当目标酶(一种水解酶)裂解多肽时，染料从纳米颗粒上解离，染料的发射被猝灭--测量这种猝灭的速度可以指示酶的活性。这种纳米技术已经被证明用于传感几种不同的蛋白水解酶(蛋白质裂解酶)，在我们的工作中，我们希望证明该技术可以扩展到量子点以外的发光纳米材料，这些发光纳米材料显示出新的和令人兴奋的光学性质(例如，用于高度多路复用的非常尖锐的量子板发射，或者用于在高散射介质中传感的上转换稀土纳米粒子)。我们将为这些纳米粒子生成新的表面化学物质，以产生最佳的传感结果。这位博士生将合成按照上述机制工作的酶活性纳米颗粒，从量子点开始，然后探索量子纳米小片，并将稀土纳米颗粒上转换为新的替代品。表面化学将被设计用来分别测量肝纤维化和胰腺炎的标志的酶基质金属蛋白酶1(MMP1)或人胰腺脂肪酶-血液生物标志物的活性。学生将演示在血液中感应的概念证明，并开始将纳米颗粒应用到实际的分析中。这将与生物医学工程(微流体和纳米制造)和医学的合作者一起进行。在项目期间，学生将获得纳米材料合成、修饰和表征方面的实用技能；并将有机会将他们改良的纳米颗粒应用于一系列相关项目。例如，将有兴趣研究(与合作者一起)开发的纳米技术是否可以与高通量筛选用于处理塑料废物的改良和进化酶相兼容，作为替代应用。这项工作符合EPSRC的医疗保健技术、物理科学和未来制造(领域包括：化学生物学、分析科学、传感器和仪器)的主题。我们的目标是提供有助于正在进行的医学范式向分层/个性化治疗转变的工具。通过实现近患者形式的酶活性快速筛查，可以改进诊断、药物选择和剂量监测。在这项工作的过程中，我们还将加深对纳米颗粒表面及其与酶等生物制剂相互作用的理解。这一新知识将通过与合作者合作、在科学文献和相关会议上广泛传播。

Many disease states can be indicated by the relative activity of a particular enzyme and many drugs are targeted to up- or down-regulate enzyme activity. Enzymes are now also being used beyond biomedical science, in industrial processes, being synthetically modified to target the degradation and recycling of plastics and production of fuels. Therefore, we aim to develop simple, accurate enzyme activity assays that can ultimately be (1) multiplexed to detect several different enzymes at once and (2) miniaturised into high-throughput devices. These assays are based on the modification of the surface of luminescent nanomaterials such as "quantum dots" to create enzyme sensors. For example, a peptide bearing a terminal dye can be bound to the surface of a quantum dot nanoparticle. The dye fluorescence is excited by the luminescence from the nanoparticle (via resonant energy transfer). On cleavage of the peptide by a target enzyme (a hydrolase), the dye is dissociated from the nanoparticle and the dye emission is quenched - measuring the rate of this quenching gives an indication of enzyme activity. Such nanotechnologies have been demonstrated for the sensing of several different proteases (protein cleaving enzymes), and in our work we hope to demonstrate that the technique is extensible to luminescent nanomaterials beyond quantum dots, that display new and exciting optical properties (e.g. the very sharp emission of quantum plates for high degrees of multiplexing, or upconverting lanthanide nanoparticles for sensing in highly scattering media). We will generate novel surface chemistries of these nanoparticles to produce the best sensing results. The PhD student will synthesise enzyme reactive nanoparticles that operate on the mechanism described above, starting with quantum dots and moving on to explore quantum nanoplatelets and upconverting lanthanide nanoparticles as novel alternatives. The surface chemistry will be designed to measure the activity of enzyme Matrix Metalloprotease 1 (MMP1) or human pancreatic lipase - blood biomarkers of markers of liver fibrosis and pancreatitis respectively. The student will demonstrate proof-of-concept of sensing in blood, and begin working to incorporate the nanoparticles into practical assays. This will be undertaken with collaborators in biomedical engineering (microfluidics and nanofabrication) and medicine. During the project, the student will gain practical skills in nanomaterials synthesis, modification and characterisation; and will have opportunities to apply their modified nanoparticles to a range of related projects. For example, it will be of interest to investigate (with collaborators) if the developed nanotechnology can be made compatible with high throughput screening of modified and evolved enzymes for treating plastic waste, as an alternative application. The work fits within EPSRC themes of Healthcare Technologies, Physical Sciences and Manufacturing the Future (areas include: Chemical Biology, Analytical Science, Sensors and Instrumentation). We aim to provide tools that will contribute to the ongoing paradigm shift in medicine towards stratified/personalised treatment. By enabling the rapid screening of enzyme activity in a near-patient format, diagnosis, drug selection, and dosage monitoring can be improved. During the course of this work we will also advance our understanding of nanoparticle surfaces and their interaction with biological agents such as enzymes. This new knowledge will be disseminated widely, via work with collaborators, in the scientific literature and at relevant conferences.