Massad-Ivanir Naama, Mirsky Yossi, Nahor Amit, Edrei Eitan, Bonanno-Young Lisa M, Ben Dov Nadav, Sa'ar Amir, Segal Ester
Department of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
Analyst. 2014 Aug 21;139(16):3885-94. doi: 10.1039/c4an00364k.
The task of rapid detection and identification of bacteria remains a major challenge in both medicine and industry. This work introduces a new concept for the design of self-reporting optical structures that can detect and quantify bacteria in real-time. The sensor is based on a two-dimensional periodic structure of porous Si photonic crystals in which the pore size is adjusted to fit the target bacteria cells (Escherichia coli). Spontaneous bacteria capture within the pores induces measurable changes in the zero-order reflectivity spectrum collected from the periodic structure. Confocal laser microscopy and electron microscopy confirm that the Escherichia coli cells are individually imprisoned within the porous array. A simple model is suggested to correlate the optical readout and the bacteria concentration and its predictions are found to be in good agreement with experimental results. In addition, we demonstrate that sensing scheme can be easily modified to potentially allow monitoring of concentration, growth and physiological state of bacteria cells. This generic platform can be tailored to target different microorganisms by tuning the array periodicity and its surface chemistry for rapid and label-free detection outside the laboratory environment.
细菌的快速检测和鉴定任务在医学和工业领域仍然是一项重大挑战。这项工作引入了一种用于设计自报告光学结构的新概念，该结构能够实时检测和量化细菌。该传感器基于多孔硅光子晶体的二维周期性结构，其中孔径经过调整以适配目标细菌细胞（大肠杆菌）。孔内细菌的自发捕获会在从周期性结构收集的零级反射光谱中引起可测量的变化。共聚焦激光显微镜和电子显微镜证实，大肠杆菌细胞被单独囚禁在多孔阵列中。提出了一个简单模型来关联光学读数与细菌浓度，并且发现其预测结果与实验结果高度吻合。此外，我们证明该传感方案可以轻松修改，从而有可能实现对细菌细胞浓度、生长和生理状态的监测。通过调整阵列周期性及其表面化学性质，这个通用平台可以针对不同微生物进行定制，以便在实验室环境之外进行快速且无标记的检测。
