Novel label-free tool for infections diagnosis based on Nano-Electro Optical Tweezers

在项目的第三年，我使用COMSOL多物理软件从理论上研究了设备的电磁场增强。我设计和制造了与单个细菌体积相当的纳米孔大小，以便捕获靠近强场区域流动的微生物，从而允许在单细胞水平上进行研究。当捕获器充满时，被捕获的细菌周围没有能量，因此防止了，或者至少显著降低了另一种细菌被困在同一区域的可能性。此外，通过引入纳米孔阵列，许多捕获位置同时被激活；因此，所提出的方法能够在局部明确的位置同时分析几个细菌。通过排列纳米孔，将获得多个并行签名，在相互作用非常弱的情况下允许测量信号。我找到了所提出的装置的理论共振模式。使用添加到周围介质中的抗生素，我用拉曼光谱研究了被捕获的细菌的生长、存活和繁殖机制。不幸的是，结果并不好。因此，我分析了细菌生长阶段的SERS信号。在我的研究中，我发现酰胺蛋白特征峰的强度在指数阶段增加，在稳定期减少。计算结果与理论解释相吻合。

I studied theoretically the enhancement of the electromagnetic field of the device using Comsol Multiphysics software in my third year of the project. I have designed and fabricated the size of the nano-aperture comparable to the volume of a single-bacterium so that the microorganism flowing close to the region with a strong field will be trapped, permitting studies at the single-cell level. When the trap was full, there is not energy confined around the trapped bacterium, so preventing, or at least remarkably reducing the probability, that another bacterium will be trapped in the same region. Moreover, by introducing an array of nanohole, many trapping sites have be activated at the same time; hence the proposed approach enabled the simultaneous analysis of several bacteria locally in well-defined positions. By arraying the nanohole, multiple signatures in parallel will be obtained, permitting a measurable signal in case of very weak interaction.I found the theoretical resonance modes of the proposed device. Using antibiotics added to the surrounding medium, I have examined the growth, survival, and reproduction mechanisms of the trapped bacteria using Raman spectroscopy. Unfortunately, the results are not good. As a result, I analyzed the SERS signal during the growth stages of the bacteria. In my study, I found that the intensity of the amide protein characteristics peaks increases during exponential phases and decreases during stationary phases. The results are in agreement with the theoretical explanations.