Present status of, and future prospects for, upconverting phosphors in proximity-based bioassay

Morgan, Christopher G.; Dad, Shakeela; Mitchell, Andrew C.

doi:10.1016/j.jallcom.2007.04.124

Cited by 32 publications

(16 citation statements)

References 19 publications

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“…Moreover, NIR light is safe to tissue which it can penetrate to a depth of up to several mm. [33,34] UCLNPs have found applications in chemical sensing, [35] labeling of biomolecules, [36][37][38][39] in enzymatic and affinity assays, [40,41] and in intracellular sensing of temperature [42] because of their brightness and other attractive features. Despite many studies on the spectral properties of UCLNPs, it is rather surprising that the quenching of their luminescence by heavy metal (HM) ions has not been investigated so far.…”

Section: Introductionmentioning

confidence: 99%

Quenching of the Luminescence of Upconverting Luminescent Nanoparticles by Heavy Metal Ions

Saleh

Ali

Wolfbeis

2011

Chemistry A European J

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We report that the luminescence of upconverting luminescent nanoparticles (UCLNPs) is quenched by heavy metal ions and halide ions in aqueous solution. The UCLNPs consist of hexagonal NaYF(4) nanocrystals doped with trivalent rare earth ions and were synthesized by both the oleic acid (solvothermal) method and the ethylenediaminetetraacetic acid (co-precipitation) method. Quenching was studied for the Cu(II), Hg(II), Pb(II), Cd(II), Co(II), Ag(I), Fe(III), Zn(II), bromide, and iodide ions and is found to be particularly strong for Hg(II). Stern-Volmer plots are virtually linear up to quencher concentrations of 10-25 mM, but deviate from linearity at higher quencher concentrations, because static quenching causes an additional effect. The UCLNPs display two main emission bands (blue, green, red or near-infrared), and the quenching efficiencies for these are found to be different. The effect seems to be generally associated with UCLNPs because it was observed for all UCLNPs doped with trivalent lanthanide ions including Yb(III), Er(III), Ho(III), and Tm(III). The results are discussed in terms of quenching mechanisms and with respect to potential applications such as optical sensing.

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Section: Introductionmentioning

confidence: 99%

Quenching of the Luminescence of Upconverting Luminescent Nanoparticles by Heavy Metal Ions

Saleh

Ali

Wolfbeis

2011

Chemistry A European J

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“…Upconverting nanocrystals that are dispersible in water are interesting materials for biotagging application since the excitation with NIR light strongly reduces the autofluorescence background of the biomaterials in the visible range. [37][38][39][40] In order to increase the optical efficiency of doped nanocrystals a shell of pure (undoped) host material was grown around the particles which separates the light emitting ions from solvent molecules and ligands. [41][42][43] Very recently the formation of shells on rare earth doped NaYF 4…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Optical Properties of KYF₄/Yb, Er Nanocrystals, and their Surface Modification with Undoped KYF₄

Schäfer

Ptáček

Zerzouf

et al. 2008

Adv Funct Materials

211

129

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KYF4/Yb3+, Er3+ nanocrystals with a mean diameter of approximately 13 nm were synthesized at 200 °C in the high boiling organic solvent N‐(2‐hydroxyethyl)ethylenediamine (HEEDA). The particles crystallize in the cubic phase known from α‐NaYF4 and form transparent colloidal solutions in tetraethylene glycol (TEG) or propanol. Solutions containing 1 wt % of the nanocrystals in TEG display visible upconversion emission upon continuous wave (CW) excitation at 978 nm. Growing undoped KYF4 on the surface of the KYF4/Yb3+, Er3+ nanocrystals increases the upconversion efficiency by more than a factor of 20. The XRD data of these particles, display a slight increase in the mean particle size from 13 to 15.5 nm, indicating that only a part of the subsequently added KYF4 shell material is deposited onto the particle surface. Nevertheless the performed surface modification obviously leads to core/shell structured particles.

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“…Morgan et al [20] reported that one particular commercial UCP bulk material contained differing UCP particles, from which part produced a dominantly red emission while the others were mainly emitting at green wavelengths. We confirmed the finding with help from Leiden University Medical Center (Leiden, the Netherlands).…”

Section: Challenges Of Ucp Labelsmentioning

confidence: 99%

“…All the three above-mentioned depopulation paths of the intermediate state E 1 should be minimized in order to increase the excited state lifetime and, consequently, the upconversion efficiency. The lifetime defines the excitation power density needed for generation of photon upconversion [20].…”

Section: Introductionmentioning

confidence: 99%

Upconverting Phosphor Labels for Bioanalytical Assays

Riuttamäki

Soukka

2013

Advances in Chemical Bioanalysis

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Upconverting phosphors (UCPs) are photoluminescent inorganic crystals capable of photon upconversion upon absorption of two or more sequential photons. UCPs produce bright, structured emission at wavelengths shorter than the excitation radiation rendering them highly advanced labels for bioanalytical assays. The exceptional anti-Stokes emission allows total elimination of autofluorescence originating mainly from biomolecules and other sample components. UCPs are excited with near-infrared radiation which provides several advantages over ultraviolet excitation-including optimal penetration of biological material. This chapter summarizes the bioanalytical in vitro applications of UCPs and discusses the advantages and challenges of the emerging label technology. In addition, synthesis of the UCP labels and some of the instruments used for UCP detection are shortly reviewed. Bioimaging and therapeutic applications based on UCPs are outside of the scope of this chapter.

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Present status of, and future prospects for, upconverting phosphors in proximity-based bioassay

Cited by 32 publications

References 19 publications

Quenching of the Luminescence of Upconverting Luminescent Nanoparticles by Heavy Metal Ions

Quenching of the Luminescence of Upconverting Luminescent Nanoparticles by Heavy Metal Ions

Synthesis and Optical Properties of KYF₄/Yb, Er Nanocrystals, and their Surface Modification with Undoped KYF₄

Upconverting Phosphor Labels for Bioanalytical Assays

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Present status of, and future prospects for, upconverting phosphors in proximity-based bioassay

Cited by 32 publications

References 19 publications

Quenching of the Luminescence of Upconverting Luminescent Nanoparticles by Heavy Metal Ions

Quenching of the Luminescence of Upconverting Luminescent Nanoparticles by Heavy Metal Ions

Synthesis and Optical Properties of KYF4/Yb, Er Nanocrystals, and their Surface Modification with Undoped KYF4

Upconverting Phosphor Labels for Bioanalytical Assays

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Synthesis and Optical Properties of KYF₄/Yb, Er Nanocrystals, and their Surface Modification with Undoped KYF₄