Wei Liping, Tian Yi, Yan Wenrong, Cheung Kawai, Ho Derek
Department of Materials Science and Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong.
Anal Bioanal Chem. 2019 Jun;411(16):3641-3652. doi: 10.1007/s00216-019-01847-6. Epub 2019 Apr 30.
Liquid-core waveguide (LCW) has many advantages such as the elimination of optical artifacts typically exhibited in systems employing lenses and filters. However, due to the effect of temporal dispersion, LCWs are typically employed in steady-state fluorescence detection microsystems rather than in fluorescence lifetime measurement (FLM) systems. In this paper, we present a compact liquid-core waveguide time-correlated single-photon counting (LCW-TCSPC) sensor for FLM. The propagation of excitation within the LCW is analyzed both analytically and in simulations, with results in agreement with experimental characterization. Results reveal an optimal region within the LCW for highly accurate FLM. The proposed prototype achieves excellent excitation rejection and low temporal dispersion as a result of optimization of the propagation length of the excitation within the LCW. The prototype achieves a detection limit of 5 nM for Coumarin 6 in dimethyl sulfoxide with < 3% lifetime error. The techniques proposed for analyzing the LCW for TCSPC based FLM and prototype demonstration pave the way for developing high-performance fluorescence lifetime measurement for microfluidics and point-of-care applications. Graphical abstract A compact liquid-core waveguide time-correlated single-photon counting (LCW-TCSPC) sensor for fluorescence lifetime measurement (FLM) is presented. Results reveal an optimal propagation length region within the LCW for highly accurate FLM. The prototype achieves a detection limit of 5 nM for Coumarin 6 in dimethyl sulfoxide with < 3% lifetime error.
液芯波导（LCW）具有许多优点，例如可消除在使用透镜和滤光片的系统中通常出现的光学伪影。然而，由于时间色散的影响，LCW通常用于稳态荧光检测微系统，而非荧光寿命测量（FLM）系统。在本文中，我们展示了一种用于FLM的紧凑型液芯波导时间相关单光子计数（LCW-TCSPC）传感器。对LCW内激发光的传播进行了分析和模拟，结果与实验表征一致。结果揭示了LCW内实现高精度FLM的最佳区域。由于优化了LCW内激发光的传播长度，所提出的原型实现了出色的激发抑制和低时间色散。该原型对二甲基亚砜中的香豆素6实现了5 nM的检测限，寿命误差<3%。所提出的用于基于TCSPC的FLM分析LCW的技术以及原型演示为开发用于微流控和即时检测应用的高性能荧光寿命测量铺平了道路。图形摘要展示了一种用于荧光寿命测量（FLM）的紧凑型液芯波导时间相关单光子计数（LCW-TCSPC）传感器。结果揭示了LCW内实现高精度FLM的最佳传播长度区域。该原型对二甲基亚砜中的香豆素6实现了5 nM的检测限，寿命误差<3%。
