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Title: A portable time-domain LED fluorimeter for nanosecond fluorescence lifetime measurements

Fluorescence lifetime measurements are becoming increasingly important in chemical and biological research. Time-domain lifetime measurements offer fluorescence multiplexing and improved handling of interferers compared with the frequency-domain technique. In this paper, an all solid-state, filterless, and highly portable light-emitting-diode based time-domain fluorimeter (LED TDF) is reported for the measurement of nanosecond fluorescence lifetimes. LED based excitation provides more wavelengths options compared to laser diode based excitation, but the excitation is less effective due to the uncollimated beam, less optical power, and longer latency in state transition. Pulse triggering and pre-bias techniques were implemented in our LED TDF to improve the peak optical power to over 100 mW. The proposed pulsing circuit achieved an excitation light fall time of less than 2 ns. Electrical resetting technique realized a time-gated photo-detector to remove the interference of the excitation light with fluorescence. These techniques allow the LED fluorimeter to accurately measure the fluorescence lifetime of fluorescein down to concentration of 0.5 μM. In addition, all filters required in traditional instruments are eliminated for the non-attenuated excitation/emission light power. These achievements make the reported device attractive to biochemical laboratories seeking for highly portable lifetime detection devices for developing sensors based on fluorescence lifetime changes.more » The device was initially validated by measuring the lifetimes of three commercial fluorophores and comparing them with reported lifetime data. It was subsequently used to characterize a ZnSe quantum dot based DNA sensor.« less
Authors:
;  [1] ;  [2] ; ;  [3] ;  [2]
  1. Electrical and Computer Engineering Department, University of Massachusetts, Amherst, Massachusetts 01003 (United States)
  2. (United States)
  3. Center for Personalized Health Monitoring, University of Massachusetts, Amherst, Massachusetts 01003 (United States)
Publication Date:
OSTI Identifier:
22254881
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 5; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 60 APPLIED LIFE SCIENCES; CONCENTRATION RATIO; DNA; EXCITATION; FLUORESCEIN; FLUORESCENCE; LIGHT EMITTING DIODES; PHOTODETECTORS; PULSE CIRCUITS; QUANTUM DOTS; SENSORS; ZINC SELENIDES