Sensors 2015, 15(3), 4890-4898; https://doi.org/10.3390/s150304890
Ultra-Sensitive Nanofiber Fluorescence Detection in a Microfluidic Chip
State Key Laboratory of Modern Optical Instrumentation, Department of Optical Engineering, Zhejiang University, Hangzhou 310027, China
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Academic Editor: Kwang W. Oh
Received: 30 December 2014 / Revised: 11 February 2015 / Accepted: 13 February 2015 / Published: 26 February 2015
(This article belongs to the Special Issue On-Chip Sensors)
Abstract
We report an ultra-sensitive and robust fluorescence sensor made by using a biconical taper with a waist diameter of 720 nm for both excitation and fluorescence collection. To enhance the stability of the fluorescence sensor, the biconical taper has been embedded in a 125 µm wide microchannel with a detection length of 2.5 cm. Investigated by measuring the fluorescence intensity of rhodamine 6G (R6G), the sensor shows a detection limit down to 100 pM, with excellent reversibility in a concentration range of 0–10 nM. The sensor has also been applied to quantum dot (QD)-labeled streptavidin measurements, yielding a detection sensitivity down to 10 pM for QDs. In addition, the small sample volume (ca. 500 nL), high sampling throughput, and seamless connection between the biconical taper and standard optical fibers offer a number of attractive advantages for chemical and biosensing applications. View Full-Text
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Li, Z.; Xu, Y.; Fang, W.; Tong, L.; Zhang, L. Ultra-Sensitive Nanofiber Fluorescence Detection in a Microfluidic Chip. Sensors 2015, 15, 4890-4898.