Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA.
Lab Chip. 2013 Nov 7;13(21):4231-8. doi: 10.1039/c3lc50785h.
We demonstrate a digital sensing platform, termed Albumin Tester, running on a smart-phone that images and automatically analyses fluorescent assays confined within disposable test tubes for sensitive and specific detection of albumin in urine. This light-weight and compact Albumin Tester attachment, weighing approximately 148 grams, is mechanically installed on the existing camera unit of a smart-phone, where test and control tubes are inserted from the side and are excited by a battery powered laser diode. This excitation beam, after probing the sample of interest located within the test tube, interacts with the control tube, and the resulting fluorescent emission is collected perpendicular to the direction of the excitation, where the cellphone camera captures the images of the fluorescent tubes through the use of an external plastic lens that is inserted between the sample and the camera lens. The acquired fluorescent images of the sample and control tubes are digitally processed within one second through an Android application running on the same cellphone for quantification of albumin concentration in the urine specimen of interest. Using a simple sample preparation approach which takes ~5 min per test (including the incubation time), we experimentally confirmed the detection limit of our sensing platform as 5-10 μg mL(-1) (which is more than 3 times lower than the clinically accepted normal range) in buffer as well as urine samples. This automated albumin testing tool running on a smart-phone could be useful for early diagnosis of kidney disease or for monitoring of chronic patients, especially those suffering from diabetes, hypertension, and/or cardiovascular diseases.
我们展示了一种基于智能手机的数字传感平台，称为白蛋白检测仪，它可以对荧光检测进行成像和自动分析，该检测被限制在一次性试管内，用于对尿液中的白蛋白进行敏感和特异性检测。这种轻便紧凑的白蛋白检测仪附件重约 148 克，通过机械方式安装在智能手机现有的摄像单元上，测试管和对照管从侧面插入，并由电池供电的激光二极管激发。这个激发光束在探测位于测试管内的感兴趣样本后，与对照管相互作用，产生的荧光发射沿垂直于激发方向被收集，在该方向上，手机摄像头通过使用插入在样本和相机镜头之间的外部塑料透镜来捕捉荧光管的图像。样本管和对照管的采集荧光图像通过在同一部手机上运行的 Android 应用程序在一秒内进行数字处理，以定量感兴趣尿液样本中的白蛋白浓度。通过使用一种简单的样品制备方法，每个测试大约需要 5 分钟（包括孵育时间），我们在缓冲液和尿液样本中实验性地证实了我们的传感平台的检测限为 5-10 μg mL(-1)（比临床可接受的正常范围低 3 倍以上）。这种在智能手机上运行的自动化白蛋白检测工具可用于早期诊断肾脏疾病或监测慢性患者，特别是患有糖尿病、高血压和/或心血管疾病的患者。
