title: A luminescence lifetime assisted ratiometric fluorimeter for biological applications.
abstract: In general, the most difficult task in developing devices for fluorescence ratiometric sensing is the isolation of signals from overlapping emission wavelengths. Wavelength discrimination can be achieved by using monochromators or bandpass filters, which often lead to decreased signal intensities. The result is a device that is both complex and expensive. Here we present an alternative system--a low-cost standalone optical fluorimeter based on luminescence lifetime assisted ratiometric sensing (LARS). This paper describes the principle of this technique and the overall design of the sensor device. The most significant innovation of LARS is the ability to discriminate between two overlapping luminescence signals based on differences in their luminescence decay rates. Thus, minimal filtering is required and the two signals can be isolated despite significant overlap of luminescence spectra. The result is a device that is both simple and inexpensive. The electronic circuit employs the lock-in amplification technique for the signal processing and the system is controlled by an onboard microcontroller. In addition, the system is designed to communicate with external devices via Bluetooth.
authors.affiliation: Department of Chemical and Biochemical Engineering, Center of Advanced Sensor Technology, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, USA.
authors.forename: Hung
authors.initials: H
authors.lastname: Lam
authors.forename: Yordan
authors.initials: Y
authors.lastname: Kostov
authors.forename: Govind
authors.initials: G
authors.lastname: Rao
authors.forename: Leah
authors.initials: L
authors.lastname: Tolosa
mesh_terms: D000465:Algorithms; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry; D005470:Fluorometry / Q000191:economics / Q000295:instrumentation*; D005947:Glucose / Q000737:chemistry; D005973:Glutamine / Q000737:chemistry; D049449:Luminescence; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation; D013686:Telemetry / Q000295:instrumentation; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D011506:Proteins; D014867:Water; D005973:Glutamine; D005947:Glucose