An optofluidic, surface-enhanced Raman spectroscopy (SERS) platform was developed to detect airborne microorganisms, continuously and in real time. The platform consists of an on-chip analysis system integrated with an aerosol sampler and Raman spectrometer. A stratified two-phase flow, consisting of the sampled air stream and a stream of collection medium, is formed in the curved channel. The inertia of collected particles, such as bacterial cells, carries them across the phase boundary in the curved channel such that they impact the liquid stream directly. The collection efficiency of the microchannel was evaluated using different-sized standard polystyrene-latex particles. A collection efficiency of 99.6% was attained for particles with an average aerodynamic diameter of 1 μm, a typical size for bacterial aerosols, by optimizing the flow rates of the sample air and liquid medium. A silver colloid in the collection medium was used as the SERS adsorbent. After passing through a serpentine mixing channel, bacterial particles were detected by SERS in real time using the custom Raman spectroscopy system. The detection system was evaluated with five test bacteria: S. epidermidis, M. luteus, E. hirae, B. subtilis, and E. coli. The concentration of airborne S. epidermidis corresponded to a Raman peak at 732.5 cm⁻¹. The limit of detection was approximately 10² CFU/mL and the total bacterial aerosol concentration was determined in real time based on the ratio of sampling air to SERS colloid.

开发了一种光流体表面增强拉曼光谱（SERS）平台，以连续不断地实时检测空气中的微生物。该平台由与气溶胶采样器和拉曼光谱仪集成的片上分析系统组成。在弯曲通道中形成了由采样空气流和收集介质流组成的分层两相流。收集的颗粒（例如细菌细胞）的惯性将它们带过弯曲通道中的相界，从而使它们直接撞击液体流。使用不同尺寸的标准聚苯乙烯-乳胶颗粒评估微通道的收集效率。对于平均空气动力学直径为1μm（细菌气雾剂的典型尺寸）的颗粒，其收集效率达到了99.6％，通过优化样品空气和液体介质的流速。收集介质中的银胶体用作SERS吸附剂。通过蛇形混合通道后，使用自定义拉曼光谱系统通过SERS实时检测细菌颗粒。用五种测试细菌评估了检测系统：表皮葡萄球菌，黄曲霉，平肠埃希氏菌，枯草芽孢杆菌和大肠杆菌。空气传播的表皮葡萄球菌的浓度对应于732.5cm ^-1处的拉曼峰。检测极限约为10 ²  CFU / mL，并根据采样空气与SERS胶体的比率实时确定总细菌气溶胶浓度。