Two-Photon Quantum Dot Excitation during Optical Trapping

Jauffred, Liselotte; Oddershede, Lene B.

doi:10.1021/nl100924z

Cited by 68 publications

(89 citation statements)

References 21 publications

(49 reference statements)

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“…Although this is an estimation of the overall size, the shape is not taken into account, and the values become rather inaccurate for QDs with elongated (ellipsoidal rather than spherical) shapes, which is very often the case. [30][31][32] Recently, we demonstrated the use of ten different LTC-QD pairs for ultrasensitive multiplexed diagnostics. [33] Herein, we show that the LTC-QD pairs can also be used as a multiplexed molecular ruler.…”

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confidence: 99%

A Quantum‐Dot‐Based Molecular Ruler for Multiplexed Optical Analysis

et al. 2010

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In memory of Theodor Förster on the centenary of his birth on May 15th 2010Applications based on Förster resonance energy transfer (FRET) play an important role in the determination of concentrations and distances within nanometer-scale systems in vitro and in vivo in the fields of biology, biochemistry, medicine, and other life sciences. [1][2][3] Due to the r À6 distance dependence of FRET, structural changes of molecular systems in the 1-10 nm range can be measured with high accuracy far below the light diffraction limit. Stryer et al. [4,5] demonstrated the spectroscopic ruler FRET technique more than 40 years ago, and it is still frequently used for in-and exvivo studies of inter-and intramolecular interactions by spectroscopy and microscopy down to the single-molecule level.[6-9] Several FRET-based biosensors for functional intracellular investigations have been developed. [10][11][12][13][14] Although most of these applications use single sensors, there have been some recent developments of dual FRET pairs for cellular imaging using fluorescent proteins, [15][16][17] and even with a single excitation wavelength.[18] Using a multiplexed FRET technique allows the simultaneous measurement of multiple distances or conformational changes, thereby decreasing time and effort whilst increasing bioanalytical information due to the possible correlation of simultaneous events.The FRET pair combination of luminescent terbium complexes (LTCs) as donors and semiconductor quantum dots (QDs) as acceptors holds significant advantages concerning sensitivity, distance, and multiparametric analysis compared to other donor-acceptor pairs. [19,20] Due to large overlap integral values, exceptionally long Förster radii (R 0 , the donor-acceptor distance at which the FRET efficiency is 50 %) of up to 11 nm can be achieved, [21][22][23] whereas conventional donor-acceptor pairs have much smaller R 0 values that rarely exceed 6 nm.[24] Although nanoplasmonic molecular rulers have been developed for which distances of up to about 70 nm can be measured, [25,26] these applications use relatively large noble metal nanoparticles (up to 40 nm) and are restricted in their multiplexed use of simultaneously measuring variable distances of different systems (for example, several different intracellular functional events within one measurement). The pioneering work of Weiss et al. demonstrated multiplexed optical rulers using quantum dots and ultrahigh-resolution colocalization (UHRC).[27] Although FRET has advantages concerning resolution accuracy and dynamic measurements, [28] UHRC is well-suited to measuring distances in the range of few nanometers to tens of micrometers. [29] Two very important aspects for intracellular studies with QDs are the shape and the size of these nanosensors, which can be crucial, for example, for cell penetration and for evaluation of the nanoparticle impact on the targeted biomolecules. Measuring the core/shell dimensions of the semiconductor material with TEM is possible with relatively good accuracy. However, ...

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confidence: 99%

A Quantum‐Dot‐Based Molecular Ruler for Multiplexed Optical Analysis

et al. 2010

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“…The trapping constant obtained for these modified UCNPs is found to be even larger than those reported for CdSe‐QDs (1.6 fN·nm −1 ·W −1 ), 36 nm Au nanoparticles (5 fN·nm −1 ·W −1 ) and 40 nm Ag nanoparticles (9 fN·nm −1 ·W −1 ). [4b,e,6,12] From data included in Figure (b), corresponding to the trapping constant obtained for all the samples under investigation in this work, it is evident that the trapping constant increases as the Z potential becomes more negative although not in an homogenous way. At this point, it should be noted that all along this work, optical forces have been obtained by considering that the UCNP particle size (accounting also for the surface coating size) is not affected by surface charge modification procedure.…”

Section: Resultsmentioning

confidence: 76%

Enhancing Optical Forces on Fluorescent Up‐Converting Nanoparticles by Surface Charge Tailoring

Rodríguez-Rodríguez

Rodríguez‐Sevilla

Ortgies

et al. 2014

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3D remote control of multifunctional fluorescent up-converting nanoparticles (UCNPs) using optical forces is being required for a great variety of applications including single-particle spectroscopy, single-particle intracellular sensing, controlled and selective light-activated drug delivery and light control at the nanoscale. Most of these potential applications find a serious limitation in the reduced value of optical forces (tens of fN) acting on these nanoparticles, due to their reduced dimensions (typically around 10 nm). In this work, this limitation is faced and it is demonstrated that the magnitude of optical forces acting on UCNPs can be enhanced by more than one order of magnitude by a controlled modification of the particle/medium interface. In particular, substitution of cationic species at the surface by other species with higher mobility could lead to UCNPs trapping with constants comparable to those of spherical metallic nanoparticles.

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“…Particles in the optical trap were selectively excited through two-photon absorption of the trapping laser. 6 This non-resonant excitation mechanism ensures that the polarisation is not inherited from the pump laser. The emission was collected through the trapping objective and was spectrally separated from the trapping beam using an infrared cold mirror.…”

Section: Methodsmentioning

confidence: 99%

Spinning nanorods – active optical manipulation of semiconductor nanorods using polarised light

et al. 2012

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In this letter we show how a single beam optical trap offers the means for three-dimensional manipulation of semiconductor nanorods in solution. Furthermore rotation of the direction of the electric field provides control over the orientation of the nanorods, which is shown by polarisation analysis of two photon induced fluorescence. Statistics over tens of trapped agglomerates reveal a correlation between the measured degree of polarisation, the trap stiffness and the intensity of the emitted light, confirming that we are approaching the single particle limit.

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Two-Photon Quantum Dot Excitation during Optical Trapping

Cited by 68 publications

References 21 publications

A Quantum‐Dot‐Based Molecular Ruler for Multiplexed Optical Analysis

A Quantum‐Dot‐Based Molecular Ruler for Multiplexed Optical Analysis

Enhancing Optical Forces on Fluorescent Up‐Converting Nanoparticles by Surface Charge Tailoring

Spinning nanorods – active optical manipulation of semiconductor nanorods using polarised light

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