Mobile Phone Ratiometric Imaging Enables Highly Sensitive Fluorescence Lateral Flow Immunoassays without External Optical Filters
Mobile Phone Ratiometric Imaging Enables Highly Sensitive Fluorescence Lateral Flow Immunoassays without External Optical Filters
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DOI：
10.1021/acs.analchem.8b01241
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发表时间：
2018-06-05
影响因子：
7.4
通讯作者：
Yager, Paul
中科院分区：
文献类型：
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作者：
Shah, Kamal G.;Singh, Vidhi;Yager, Paul
基于侧流免疫测定概念的基于纸的诊断测试承诺低成本的感染性疾病的即时检测，但是这样的测定遭受较差的检测极限。导致分析性能差的一个因素是依赖于低对比度的发色光学标记，如金纳米颗粒。先前提高纸基诊断灵敏度的尝试包括用酶、荧光团或磷光体代替发色标记，代价是增加流体复杂性或需要具有昂贵光电子器件的设备读取器。包括我们自己在内的几个团体已经提出将移动的电话作为合适的即时阅读器，因为它们成本低、易于使用和无处不在。然而，现有的移动的电话荧光读取器需要昂贵的滤光器，并且通常仅用一个相机传感器模块进行验证，这不适合潜在的护理点使用。作为回应，我们建议耦合低成本的紫外发光二极管与长斯托克斯位移量子点，使比率移动的手机荧光测量没有光学滤波器。使用未经修改的智能手机摄像头的比率成像提高了对比度，并将激发强度变化的影响衰减了15倍。通过将核蛋白掺入模拟鼻基质中的甲型流感侧流免疫测定法展示了实际应用。在两个移动的手机上达到1.5和2.6 fmol的检测限，这与凝胶成像仪（1.9 fmol）相当，比在扫描仪上成像金纳米颗粒（18 fmol）好10倍，并且比用移动的手机成像的金纳米颗粒标记的测定好>2个数量级。使用所提出的无过滤器移动的电话成像方案是实现新一代高灵敏度即时荧光测定的第一步。
Paper-based diagnostic tests based on the lateral flow immunoassay concept promise low-cost, point-of-care detection of infectious diseases, but such assays suffer from poor limits of detection. One factor that contributes to poor analytical performance is a reliance on low-contrast chromophoric optical labels such as gold nanoparticles. Previous attempts to improve the sensitivity of paper-based diagnostics include replacing chromophoric labels with enzymes, fluorophores, or phosphors at the expense of increased fluidic complexity or the need for device readers with costly optoelectronics. Several groups, including our own, have proposed mobile phones as suitable point-of-care readers due to their low cost, ease of use, and ubiquity. However, extant mobile phone fluorescence readers require costly optical filters and were typically validated with only one camera sensor module, which is inappropriate for potential point-of-care use. In response, we propose to couple low-cost ultraviolet light-emitting diodes with long Stokes-shift quantum dots to enable ratiometric mobile phone fluorescence measurements without optical filters. Ratiometric imaging with unmodified smartphone cameras improves the contrast and attenuates the impact of excitation intensity variability by 15x. Practical application was shown with a lateral flow immunoassay for influenza A with nucleoproteins spiked into simulated nasal matrix. Limits of detection of 1.5 and 2.6 fmol were attained on two mobile phones, which are comparable to a gel imager (1.9 fmol), 10x better than imaging gold nanoparticles on a scanner (18 fmol), and >2 orders of magnitude better than gold nanoparticle-labeled assays imaged with mobile phones. Use of the proposed filter-free mobile phone imaging scheme is a first step toward enabling a new generation of highly sensitive, point-of-care fluorescence assays.