Lensless CCD-based fluorometer using a micromachined optical Soller collimator
Lensless CCD-based fluorometer using a micromachined optical Soller collimator
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DOI：
10.1039/c01c00431f
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发表时间：
2011-01-01
期刊：
影响因子：
6.1
通讯作者：
Rasooly, Avraham
中科院分区：
文献类型：
--
作者：
Balsam, Joshua;Ossandon, Miguel;Rasooly, Avraham
在本文中，我们描述了一个简单的电荷耦合器件（CCD）为基础的无透镜荧光计的灵敏度范围内的电流ELISA板阅读器。在我们的无透镜荧光计中，多波长LED光源用于荧光团激发。为了对光进行准直，我们开发了一种简单的光学索勒准直器，该准直器基于“针孔堆叠”（具有用激光加工的针孔阵列的黑色PMMA堆叠），使得光能够从LED通过滤光器和测定的微流体直接准直到CCD上，而无需透镜。消除在几乎所有其它当前基于CCD的检测系统中使用的透镜具有四个主要优点：（1）它简化了装置设计和制造，同时降低了成本。(2)它缩短了样品和测量设备之间的距离（没有透镜，将图像聚焦在CCD上所需的距离缩短，荧光计可以更紧凑）。(3)它通过使用光学索勒准直器耦合CCD和被检测表面，该准直器允许使用滤光器进行荧光检测。(4)它还将CCD和微流体分离，以便能够使用可互换的流体，同时保护精密的CCD。基于无透镜CCD的荧光计能够同时检测16个样品，并且用于使用FRET测定法体外检测肉毒杆菌神经毒素血清型A（BoNT-A）活性，所述FRET测定法测量毒素轻链（LcA）对BoNT-A（SNAP-25）特异性的荧光团标记的肽底物的切割。我们的无透镜荧光计的检测限（LOD）为1.25 nM，这与现代ELISA酶标仪的LOD相似。与微流体相结合，这种简单的低成本护理点（POC）医疗诊断系统可能有助于在没有实验室的情况下进行许多其他复杂的医疗诊断测定，从而可能提高服务不足人群的医疗保健服务的可及性和质量。
In this paper, we describe a simple charge-coupled device (CCD) based lensless fluorometer with sensitivity in the range of current ELISA plate readers. In our lensfree fluorometer, a multi-wavelength LED light source was used for fluorophore excitation. To collimate the light, we developed a simple optical Soller collimator based on a "stack of pinholes'' (a stack of black PMMA with array of pinholes machined with laser) enabling the light to be collimated from the LED through the filters and the assay's microfluidics directly onto the CCD without a lens. The elimination of the lens that is used in almost all other current CCD based detection systems has four major advantages: (1) It simplifies the device design and fabrication while reducing cost. (2) It reduces the distance between the sample and the measuring device (without a lens the distance needed to focus the image on the CCD is reduced and the fluorometer can be more compact). (3) It couples the CCD and the detected surface by using an optical Soller Collimator which allows the use of filters for fluorescence detection. (4) It also uncouples the CCD and the microfluidics to enable the use of interchangeable fluidics while protecting the delicate CCD. The lensless CCD-based fluorometer is capable of detecting 16 samples simultaneously, and was used for in vitro detection of botulinum neurotoxin serotype A (BoNT-A) activity with a FRET assay that measures cleavage of a fluorophore-tagged peptide substrate specific for BoNT-A (SNAP-25) by the toxin light chain (LcA). The limit of detection (LOD) of our lensless fluorometer is 1.25 nM, which is similar to the LOD of a modern ELISA plate reader. Combined with microfluidics, this simple low cost point-of-care (POC) medical diagnostic system may be useful for the performance of many other complex medical diagnostic assays without a laboratory and thus potentially enhancing the accessibility and the quality of health care delivery in underserved populations.