Absorption is a widely used technique for a range of different applications. It has lower sensitivity than many other techniques such as fluorescence which has 100 to 1000 times higher sensitivity than absorption. Optical cavity approaches have been developed where the light passes back and forth, within the sample, between two high reflectivity mirrors to increase the pathlength and sensitivity. These approaches have not yet, however, been widely used for analytical applications and for point-of-care diagnostics. Here we show a portable cavity enhanced absorption (CEA) spectrometer and a low cost point-of-care (POC) reader with CEA detection with mechanical elements fabricated using 3D printing. The CEA spectrometer can be used in both single pass and multi-pass cavity enhanced mode to provide measurements in the visible region that are very sensitive and over a wide dynamic range. The CEA mode was shown for Rhodamine B dye to increase the pathlength 57.8 fold over single pass measurements and an LOD of 7.1 × 10⁻¹¹ M. The cost of the CEA POC reader was reduced by use of narrow band LEDs, photodiodes and removal of fibre optic coupling and with a 14 fold increase in the pathlength over conventional single pass microplate readers. The CEA POC reader was demonstrated for immunoassay of C-Reactive Protein (CRP), Procalcitonin (PCT) and Interleukin 6 (IL-6), towards a three biomarker panel to aid the diagnosis of sepsis. The CEA POC reader can be integrated with wireless connectivity for cloud based data sharing. We show here the potential for the wider use of optical cavity approaches where there is a need for sensitive absorption measurements and also for low cost point-of-care diagnostics.

中文翻译：

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便携式，低成本且灵敏的腔增强吸收（CEA）检测

吸收是一种广泛用于各种不同应用的技术。它的灵敏度低于许多其他技术，例如荧光，其灵敏度比吸收技术高10​​0至1000倍。已经开发了光学腔方法，其中光在样品中在两个高反射率镜之间来回传递，以增加光程和灵敏度。但是，这些方法尚未广泛用于分析应用程序和即时诊断。在这里，我们展示了一种便携式腔增强吸收（CEA）光谱仪和一种具有CEA检测功能且采用3D打印制造的机械元件的低成本即时点（POC）阅读器。CEA光谱仪可用于单程和多程腔增强模式，以在非常敏感的可见范围内提供动态范围内的测量。显示罗丹明B染料的CEA模式比单次通过测量增加了57.8倍的光程，LOD为7.1×10^-11M。通过使用窄带LED，光电二极管和取消光纤耦合，降低了CEA POC读取器的成本，与传统的单程微孔板读取器相比，光程增加了14倍。CEA POC阅读器已被证明可用于C反应蛋白（CRP），降钙素原（PCT）和白细胞介素6（IL-6）的免疫测定，朝着三个生物标志物组的方向进行，以帮助诊断败血症。CEA POC阅读器可以与无线连接集成在一起，用于基于云的数据共享。我们在这里显示了在需要灵敏吸收测量以及低成本即时诊断的情况下，更广泛使用光腔方法的潜力。