A UV‐Blocking Polymer Shell Prevents One‐Photon Photoreactions while Allowing Multi‐Photon Processes in Encapsulated Upconverting Nanoparticles

Wu, Tuoqi; Barker, Madeleine; Arafeh, Khaled M.; Boyer, John‐Christopher; Carling, Carl-Johan; Branda, Neil R.

doi:10.1002/ange.201305253

Cited by 9 publications

(6 citation statements)

References 29 publications

(15 reference statements)

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“…Phosphates have been shown to coordinate strongly to UCNP surfaces and are frequently used in ligand exchange reactions to generate water-soluble UCNPs. 37,47,48 Completion of the ligand exchange reaction was confirmed with FTIR spectroscopy by the disappearance of bands associated with OA, and appearance of characteristic PEA peaks (Supporting Information Figure S1). Figure 2a is a TEM image of PEA-UCNP showing monodisperse UCNPs with an approximate size of 20 nm and the absence of aggregation.…”

Section: ■ Results and Discussionmentioning

confidence: 72%

Solid-Phase Covalent Immobilization of Upconverting Nanoparticles for Biosensing by Luminescence Resonance Energy Transfer

Doughan

Han

Uddayasankar

et al. 2014

ACS Appl. Mater. Interfaces

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Monodisperse water-soluble upconverting nanoparticles (UCNPs) were immobilized onto modified glass substrates for development of biosensing surfaces that operated using luminescence resonance energy transfer (LRET). Amine modified UCNPs were prepared from oleic acid capped UCNPs by ligand exchange using o-phosphorylethanolamine (PEA). PEA-UCNPs were covalently immobilized on aldehyde functionalized coverslips. Environmental scanning electron microscopy (ESEM) images indicated a homogeneous distribution of UCNPs on surfaces with a high immobilization density of approximately 1.3 × 10(11) UCNP cm(-2). This is the first account of covalent immobilization of UCNPs for bioassay and biosensor development where the density is on par with the high immobilization densities reported for other types of nanoparticles. The functionality and stability of the immobilized NPs were demonstrated by examining an LRET-based bioassay. The well-known sandwich assay for the detection of thrombin was selected as a model in which UCNPs were used as donors and quantum dots (QDs) as acceptors. The closely packed UCNPs on the glass surface showed a 2.5-fold enhancement in assay sensitivity compared to less-densely packed surfaces. In addition, a 1.5-fold enhancement in energy transfer efficiency was shown for solid-phase compared to solution-phase LRET.

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Section: ■ Results and Discussionmentioning

confidence: 72%

Solid-Phase Covalent Immobilization of Upconverting Nanoparticles for Biosensing by Luminescence Resonance Energy Transfer

Doughan

Han

Uddayasankar

et al. 2014

ACS Appl. Mater. Interfaces

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“…[9] Encapsulation with amphiphilic polymers, whereby the hydrophobic moiety of the polymer intercalates with the oleate ligands on the surface, and the hydrophilic part remains exposed to the solution, is another strategy and yields stable colloids. [15][16][17] To impart increased stability, the coated amphiphilic polymer shell can be further cross-linked, usually on its periphery. [9,[18][19][20] Neither method is very versatile or generally applicable.…”

Section: In Memory Of Daniel Thomasmentioning

confidence: 99%

Versatile Synthetic Strategy for Coating Upconverting Nanoparticles with Polymer Shells through Localized Photopolymerization by Using the Particles as Internal Light Sources

et al. 2014

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We present a straightforward and generic strategy for coating upconverting nanoparticles (UCPs) with polymer shells for their protection, functionalization, conjugation, and for biocompatibility. UCPs are attracting much attention for their potential use as fluorescent labels in biological applications. However, they are hydrophobic and non-compatible with aqueous media; thus prior surface modification is essential. Our method uses the internal UV or visible light emitted from UCPs upon photoexcitation with near-infrared radiation, to locally photopolymerize a thin polymer shell around the UCPs. In this way, a large variety of monomers with different chemical functionalities can be incorporated. If required, a second layer can be added on top of the first. Our method can provide a large spectrum of surface functional groups rapidly and in one pot, hence offering a platform for the preparation of libraries of functional polymer-encapsulated UCPs for applications in bioassays, biosensing, optical imaging, and theranostics.

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“…4, 10–14 Although this strategy results in quite stable nanoparticles, post‐treatment is not straightforward, and certain factors, such as the inability to remove the surfactants completely, might be a problem for in vivo applications 9. Encapsulation with amphiphilic polymers, whereby the hydrophobic moiety of the polymer intercalates with the oleate ligands on the surface, and the hydrophilic part remains exposed to the solution, is another strategy and yields stable colloids 15–17. To impart increased stability, the coated amphiphilic polymer shell can be further cross‐linked, usually on its periphery 9.…”

Section: Functionalized Water‐compatible Core–shell Ucps Obtained By mentioning

confidence: 99%

Versatile Synthetic Strategy for Coating Upconverting Nanoparticles with Polymer Shells through Localized Photopolymerization by Using the Particles as Internal Light Sources

et al. 2014

View full text Add to dashboard Cite

We present a straightforward and generic strategy for coating upconverting nanoparticles (UCPs) with polymer shells for their protection, functionalization, conjugation, and for biocompatibility. UCPs are attracting much attention for their potential use as fluorescent labels in biological applications. However, they are hydrophobic and non‐compatible with aqueous media; thus prior surface modification is essential. Our method uses the internal UV or visible light emitted from UCPs upon photoexcitation with near‐infrared radiation, to locally photopolymerize a thin polymer shell around the UCPs. In this way, a large variety of monomers with different chemical functionalities can be incorporated. If required, a second layer can be added on top of the first. Our method can provide a large spectrum of surface functional groups rapidly and in one pot, hence offering a platform for the preparation of libraries of functional polymer‐encapsulated UCPs for applications in bioassays, biosensing, optical imaging, and theranostics.

show abstract

A UV‐Blocking Polymer Shell Prevents One‐Photon Photoreactions while Allowing Multi‐Photon Processes in Encapsulated Upconverting Nanoparticles

Cited by 9 publications

References 29 publications

Solid-Phase Covalent Immobilization of Upconverting Nanoparticles for Biosensing by Luminescence Resonance Energy Transfer

Solid-Phase Covalent Immobilization of Upconverting Nanoparticles for Biosensing by Luminescence Resonance Energy Transfer

Versatile Synthetic Strategy for Coating Upconverting Nanoparticles with Polymer Shells through Localized Photopolymerization by Using the Particles as Internal Light Sources

Versatile Synthetic Strategy for Coating Upconverting Nanoparticles with Polymer Shells through Localized Photopolymerization by Using the Particles as Internal Light Sources

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