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Förster Resonance Energy Transfer between Quantum Dot Donors and Quantum Dot Acceptors.

Chou KF, Dennis AM - Sensors (Basel) (2015)

Bottom Line: Förster (or fluorescence) resonance energy transfer amongst semiconductor quantum dots (QDs) is reviewed, with particular interest in biosensing applications.The brightness and photostability of QDs make them attractive for highly sensitive sensing and long-term, repetitive imaging applications, respectively, but the overlapping donor and acceptor excitation signals that arise when QDs serve as both the donor and acceptor lead to high background signals from direct excitation of the acceptor.The fundamentals of FRET within a nominally homogeneous QD population as well as energy transfer between two distinct colors of QDs are discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA. kfchou@bu.edu.

ABSTRACT
Förster (or fluorescence) resonance energy transfer amongst semiconductor quantum dots (QDs) is reviewed, with particular interest in biosensing applications. The unique optical properties of QDs provide certain advantages and also specific challenges with regards to sensor design, compared to other FRET systems. The brightness and photostability of QDs make them attractive for highly sensitive sensing and long-term, repetitive imaging applications, respectively, but the overlapping donor and acceptor excitation signals that arise when QDs serve as both the donor and acceptor lead to high background signals from direct excitation of the acceptor. The fundamentals of FRET within a nominally homogeneous QD population as well as energy transfer between two distinct colors of QDs are discussed. Examples of successful sensors are highlighted, as is cascading FRET, which can be used for solar harvesting.

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(a) Schematic of two-color QD-QD FRET Ca2+ sensor. Green donor CdTe QDs and red CdTe acceptor QDs are each coated with thioglycolic acid (TGA), imparting a negative surface charge. In the presence of the calcium cation, the QDs aggregate, bringing them in close enough proximity for energy transfer to occur efficiently. Schematic is not drawn to scale; (b) The PL spectrograph shows a decrease in the green donor emission and increase in the red acceptor emission with increasing calcium cation concentration; (c) Time-resolved PL of the green emission with increasing amounts of calcium; as the cation concentration increases, QD-QD interactions are promoted. The donor emission lifetime visibly shortens, indicating that the green QDs are acting as FRET donors; (d) Time-resolved PL of deep red emission from red-only and green-and-red-mixed QD samples. In the presence of the green donor QD, the PL lifetime of the red emission is elongated; (b–d) reprinted with permission from [76]. Copyright (2008) American Chemical Society.
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sensors-15-13288-f007: (a) Schematic of two-color QD-QD FRET Ca2+ sensor. Green donor CdTe QDs and red CdTe acceptor QDs are each coated with thioglycolic acid (TGA), imparting a negative surface charge. In the presence of the calcium cation, the QDs aggregate, bringing them in close enough proximity for energy transfer to occur efficiently. Schematic is not drawn to scale; (b) The PL spectrograph shows a decrease in the green donor emission and increase in the red acceptor emission with increasing calcium cation concentration; (c) Time-resolved PL of the green emission with increasing amounts of calcium; as the cation concentration increases, QD-QD interactions are promoted. The donor emission lifetime visibly shortens, indicating that the green QDs are acting as FRET donors; (d) Time-resolved PL of deep red emission from red-only and green-and-red-mixed QD samples. In the presence of the green donor QD, the PL lifetime of the red emission is elongated; (b–d) reprinted with permission from [76]. Copyright (2008) American Chemical Society.

Mentions: Similarly to monochromatic QD populations, FRET is observed amongst differently sized QDs of the same species, i.e., heterotransfer between two spectrally distinct, but physically co-mingled, QD populations. In a mixed population of QDs, the smaller, higher energy NCs act as donors while larger, lower emission energy NCs act as acceptors. When FRET occurs, the donor emission is quenched and the acceptor emission is enhanced (Figure 7b).


Förster Resonance Energy Transfer between Quantum Dot Donors and Quantum Dot Acceptors.

Chou KF, Dennis AM - Sensors (Basel) (2015)

(a) Schematic of two-color QD-QD FRET Ca2+ sensor. Green donor CdTe QDs and red CdTe acceptor QDs are each coated with thioglycolic acid (TGA), imparting a negative surface charge. In the presence of the calcium cation, the QDs aggregate, bringing them in close enough proximity for energy transfer to occur efficiently. Schematic is not drawn to scale; (b) The PL spectrograph shows a decrease in the green donor emission and increase in the red acceptor emission with increasing calcium cation concentration; (c) Time-resolved PL of the green emission with increasing amounts of calcium; as the cation concentration increases, QD-QD interactions are promoted. The donor emission lifetime visibly shortens, indicating that the green QDs are acting as FRET donors; (d) Time-resolved PL of deep red emission from red-only and green-and-red-mixed QD samples. In the presence of the green donor QD, the PL lifetime of the red emission is elongated; (b–d) reprinted with permission from [76]. Copyright (2008) American Chemical Society.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507609&req=5

sensors-15-13288-f007: (a) Schematic of two-color QD-QD FRET Ca2+ sensor. Green donor CdTe QDs and red CdTe acceptor QDs are each coated with thioglycolic acid (TGA), imparting a negative surface charge. In the presence of the calcium cation, the QDs aggregate, bringing them in close enough proximity for energy transfer to occur efficiently. Schematic is not drawn to scale; (b) The PL spectrograph shows a decrease in the green donor emission and increase in the red acceptor emission with increasing calcium cation concentration; (c) Time-resolved PL of the green emission with increasing amounts of calcium; as the cation concentration increases, QD-QD interactions are promoted. The donor emission lifetime visibly shortens, indicating that the green QDs are acting as FRET donors; (d) Time-resolved PL of deep red emission from red-only and green-and-red-mixed QD samples. In the presence of the green donor QD, the PL lifetime of the red emission is elongated; (b–d) reprinted with permission from [76]. Copyright (2008) American Chemical Society.
Mentions: Similarly to monochromatic QD populations, FRET is observed amongst differently sized QDs of the same species, i.e., heterotransfer between two spectrally distinct, but physically co-mingled, QD populations. In a mixed population of QDs, the smaller, higher energy NCs act as donors while larger, lower emission energy NCs act as acceptors. When FRET occurs, the donor emission is quenched and the acceptor emission is enhanced (Figure 7b).

Bottom Line: Förster (or fluorescence) resonance energy transfer amongst semiconductor quantum dots (QDs) is reviewed, with particular interest in biosensing applications.The brightness and photostability of QDs make them attractive for highly sensitive sensing and long-term, repetitive imaging applications, respectively, but the overlapping donor and acceptor excitation signals that arise when QDs serve as both the donor and acceptor lead to high background signals from direct excitation of the acceptor.The fundamentals of FRET within a nominally homogeneous QD population as well as energy transfer between two distinct colors of QDs are discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA. kfchou@bu.edu.

ABSTRACT
Förster (or fluorescence) resonance energy transfer amongst semiconductor quantum dots (QDs) is reviewed, with particular interest in biosensing applications. The unique optical properties of QDs provide certain advantages and also specific challenges with regards to sensor design, compared to other FRET systems. The brightness and photostability of QDs make them attractive for highly sensitive sensing and long-term, repetitive imaging applications, respectively, but the overlapping donor and acceptor excitation signals that arise when QDs serve as both the donor and acceptor lead to high background signals from direct excitation of the acceptor. The fundamentals of FRET within a nominally homogeneous QD population as well as energy transfer between two distinct colors of QDs are discussed. Examples of successful sensors are highlighted, as is cascading FRET, which can be used for solar harvesting.

Show MeSH