Spectral-Time Multiplexing in FRET Complexes of AgInS2/ZnS Quantum Dot and Organic Dyes

Abstract

Nowadays, multiplex analysis is very popular, since it allows to detect a large number of biomarkers simultaneously. Traditional multiplex analysis is usually based on changes of photoluminescence (PL) intensity and/or PL band spectral positions in the presence of analytes. Using PL lifetime as an additional parameter might increase the efficiency of multiplex methods. Quantum dots (QDs) can be used as luminescent markers for multiplex analysis. Ternary in-based QDs are a great alternative to the traditional Cd-based one. Ternary QDs possess all advantages of traditional QDs, including tunable photoluminescence in visible range. At the same time ternary QDs do not have Cd-toxicity, and moreover they possess long spectral dependent lifetimes. This allows the use of ternary QDs as a donor for time-resolved multiplex sensing based on Förster resonance energy transfer (FRET). In the present work, we implemented FRET from AgInS2/ZnS ternary QDs to cyanine dyes absorbing in different spectral regions of QD luminescence with different lifetimes. As the result, FRET-induced luminescence of dyes differed not only in wavelengths but also in lifetimes of luminescence, which can be used for time-resolved multiplex analysis in biology and medicine.

Lab-on-Microsphere—FRET-Based Multiplex Sensor Platform

“…It was shown that the fluorophore's long lifetimes lead to a considerable suppression of the autofluorescence background and, consequently, to the overall sensitivity improvement [29]. Broad bandwidths and long lifetimes of ternary QDs are also beneficial for the applications with Förster resonance energy transfer (FRET), where QDs can be utilized as efficient energy donors [30][31][32][33]. In this case, the donor−acceptor pairs with acceptor absorption bands overlapping QD PL at different wavelengths and lifetimes result in different lifetimes of sensitized dye PL that allow for spectral and lifetime multiplexing [30,31,34].…”

“…Broad bandwidths and long lifetimes of ternary QDs are also beneficial for the applications with Förster resonance energy transfer (FRET), where QDs can be utilized as efficient energy donors [30][31][32][33]. In this case, the donor−acceptor pairs with acceptor absorption bands overlapping QD PL at different wavelengths and lifetimes result in different lifetimes of sensitized dye PL that allow for spectral and lifetime multiplexing [30,31,34]. The combined multiplexing strategy is crucial for creating the next generation bioanalytical sensing platforms and has been a subject of intensive research in the last few years [35,36].…”

“…The designed system utilizes the time-resolved FRET from QDs (donors) to dyes (acceptors), which leads to the possibility of recording spectrally different bands of FRET-induced luminescence for each dye with different decay times. Given that the PL lifetimes of QDs increase with the wavelength, the sensitized luminescence lifetimes of the dyes depends on which part of the QD luminescence spectrum they absorb [31]. The system thereby enables to perform the potential multiplexing by wavelength and photoluminescence lifetimes of the dyes.…”

FRET-Based Analysis of AgInS2/ZnAgInS/ZnS Quantum Dot Recombination Dynamics

“…Another important subclass of applications in life sciences employs ternary QDs as energy donors in the complexes with Förster resonant energy transfer (FRET) [ 41 , 42 ]. These complexes might be used for photodynamic therapy [ 43 , 44 , 45 ] and assays for the multiplex analysis [ 46 , 47 , 48 ].…”

“…Moreover, PL lifetimes of ternary QDs are distributed along the emission band with the shorter times at higher energies and the average values of hundreds of nanoseconds [ 10 , 12 , 49 , 50 , 51 ]. Such long wavelength-dependent lifetimes are advantageous for two reasons: (a) they help to separate the short-lived autofluorescence of the biological surroundings, thereby increasing the sensitivity of a sensor [ 46 ]; (b) they allow for lifetime multiplexing—a technique which implies barcoding of luminescent labels based on their lifetimes rather that PL peak positions [ 47 , 48 , 52 , 53 , 54 ].…”