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.

In-line measurement of dissolved acetone using a nanoestructured optical sensor

“…Ratiometric techniques have emerged to reduce the problems associated to intensity measurements and lifetime measurements [7][8][9][10][11][12][13][14]. They are based on dual emission or dual excitation indicators that possess separated spectral areas with different behavior or in dynamic characteristics of the sensor.…”

Simultaneous, accurate lifetime determination of two luminophores using time-domain techniques

“…Separation of multiple emission signals using optical filters has also been demonstrated but this requires spectrally-distinct dyes and expensive optics [13][14][15]21]. As alternatives to these methods, several groups have developed methods for multi-analyte sensing using luminescence lifetime techniques without the need for separate emission filters or long computing times [8,16,17,[22][23][24][25]. These techniques instead utilize luminophores with easily distinguished lifetimes, where lifetime differentiation is dependent upon the system and algorithm.…”

A Portable Microcontrolled Pumping Flow System Developed to In Loco Determination of Diuron at Nanomolar Levels Employing a Disposable Biosensor

“…This device is able to perform commands and instructions, which are driven by a code that can be loaded and storage into the memory of the microcontroller. In analytical chemistry, microcontrollers have been used for the construction of photometers, [4] spectrophotometers, [5] fluorimeters, [6] turbidimeters, [7,8] nephelometers, [8,9] potentiostats and luminometers [10]. In order to reach a full and more versatility automation, the microcontrolled instrumentation can be coupled to flow analyses procedures.…”