Microfluidic nanotechnology for chemical sensing

在我的分析化学研究项目中，纳米技术将与微流控芯片一起用于检测化合物。虽然微芯片提供精确和快速的液体输送，纳米技术提高了传感器材料的功能，以实现传感。需要快速测定液体混合物中化合物的组成，例如由汽油和油组成的燃料混合物。虽然这种测定可以通过实验室设备进行，但这一目标很难通过简单的浸入式传感器实现。将开发一种新型传感器，它是一种纳米结构材料，如光子晶体。如果有机液体进入并弄湿纳米材料中的纳米孔，它就会改变颜色。我们将使用微流体的方法来精确地传递反应物，并控制它们在衬底上的后续反应，以生产基于光子晶体的传感器。我们将详细研究控制光子晶体中孔隙润湿的各种参数。该传感器将采用浸渍条的形式，用于各种常用燃料混合物的简单视觉测试，如汽油/油（16:1）或汽油/乙醇（95:5或E5）。在商店或家中储存燃料混合物时，液体成分会因蒸发而发生变化，因此对燃料混合物成分进行简单的家庭测试将有利于公众。*** *在传感中实现低检测限的重要途径是减少表面上的非特异性结合。不幸的是，减少非特异性吸附通常会减少特异性探针和靶标（如蛋白质或寡核苷酸）之间的结合。因此，通常以牺牲灵敏度（低特异性信号）为代价来提高特异性，因此信噪比可能得不到改善。在我的实验室，我们计划通过使用两种不同的方法来分析蛋白质和dna来解决这个问题。对于蛋白质分析，在表面使用无粘性涂层，以避免干扰物质在其上的结合，并提高血清中发现的临床相关蛋白质的检测限。对于DNA分析，金纳米颗粒用于去除非特异性物质而不去除分析物。我们将研究DNA与金纳米颗粒相互作用的机制，从而成功去除DNA分析中的干扰物。*** *在分析化学中，为了快速反应和灵敏检测，需要预先浓缩试剂。预浓缩可以通过体积缩小来实现，其中试剂被捕获在功能化颗粒上，同时溶剂被去除。然后这些化学物质以更小体积的液体释放出来，本质上增加了它们的浓度。将研究颗粒的性质（孔径、承载能力）和混合效率（湍流度、停留时间）。

Nanotechnology will be employed together with the microfluidic chip for sensing chemical compounds in my analytical chemistry research program. While the microchip provides precise and fast liquid delivery, nanotechnology improves functionality of the sensor materials to achieve sensing. There is a demand to quickly determine the compositions of chemical compounds in a liquid mixture, such as a fuel mixture consisting of gasoline and oil. Although this determination can be conducted by laboratory equipment, this goal is difficult to achieve by a simple dip-in sensor. A novel sensor, which is a nano-structured material such as the photonic crystal, will be developed. It can change color by organic liquids if they enter, and thus wet, the nano-sized pores in the nanomaterials. We will use a microfluidic method to precisely deliver reactants and control their subsequent reactions on the substrate to produce the photonic crystal-based sensor. We will examine in detail the various parameters that govern the wetting of the pores in the photonic crystals. The sensor will be in the form of a dip-in strip for simple visual testing of various commonly used fuel mixtures such as gasoline/oil (16:1) or gasoline/ethanol (95:5 or E5). The liquid compositions will change due to evaporation during storage of the fuel mixture at stores or at home, and so a simple domestic test for fuel mixture compositions will be advantageous to the general public.*** *An important way to achieve low detection limit in sensing is to reduce nonspecific binding on a surface. Unfortunately, reduction of nonspecific adsorption will usually reduce the binding between specific probes and targets, such as proteins or oligonucleotides. Therefore, specificity is usually increased at the expense of sensitivity (low specific signal), and so the signal-to-noise ratio may remain unimproved. In my lab, we plan to resolve this issue by using 2 different approaches for analysis of proteins and DNAs. For protein analysis, a non-sticky coating is used on the surface to avoid binding of interferent substances on it and to improve the detection limit of a clinically relevant protein found in serum. For DNA analysis, gold nanoparticles are used to remove nonspecific substances without removing the analytes. We will study the mechanism of interactions of DNAs with gold nanoparticles that results in the successful removal of interferents in DNA analysis. *** *In analytical chemistry, it is necessary to pre-concentrate reagents for fast reaction and sensitive detection. Pre-concentration can be achieved by volume reduction in which the reagents are captured on functionalized particles while the solvents are removed. The chemicals are then released in a smaller volume of liquid, essentially increasing their concentrations. The nature of particles (pore diameter, loading capacity) and the efficiency of mixing (turbulence, residence time) will be studied.