Sensitive Fluorometric Nanoparticle Assays for Cell Counting and Viability

Pihlasalo, Sari; Pellonperä, Lotta; Martikkala, Eija; Hänninen, Pekka; Härmä, Harri

doi:10.1021/ac1017869

Cited by 17 publications

(19 citation statements)

References 27 publications

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“…Similarly, europium-chelate-doped polystyrene beads were used for FRET experiments to detect cells and probe their viability in solution. 100 In that case, labeled BSA adsorption is prevented by the presence of cells, resulting in a FRET signal decrease depending on the number of cells in solution. The sensitivity of this method was sufficient to count five cells in solution in a microwell, which is significantly less than that of standard automated counters.…”

Section: Biochemical Applicationsmentioning

confidence: 99%

“…These performances are comparable with commercial protein titration methods. Similarly, europium-chelate-doped polystyrene beads were used for FRET experiments to detect cells and probe their viability in solution . In that case, labeled BSA adsorption is prevented by the presence of cells, resulting in a FRET signal decrease depending on the number of cells in solution.…”

Section: Biochemical Applicationsmentioning

confidence: 99%

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Biological Applications of Rare-Earth Based Nanoparticles

2011

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Biomedicine and cell and molecular biology require powerful imaging techniques of the single molecule scale to the whole organism, either for fundamental science or diagnosis. These applications are however often limited by the optical properties of the available probes. Moreover, in cell biology, the measurement of the cell response with spatial and temporal resolution is a central instrumental problem. This has been one of the main motivations for the development of new probes and imaging techniques either for biomolecule labeling or detection of an intracellular signaling species. The weak photostability of genetically encoded probes or organic dyes has motivated the interest for different types of nanoparticles for imaging such as quantum dots, nanodiamonds, dye-doped silica particles, or metallic nanoparticles. One of the most active fields of research in the past decade has thus been the development of rare-earth based nanoparticles, whose optical properties and low cytotoxicity are promising for biological applications. Attractive properties of rare-earth based nanoparticles include high photostability, absence of blinking, extremely narrow emission lines, large Stokes shifts, long lifetimes that can be exploited for retarded detection schemes, and facile functionalization strategies. The use of specific ions in their compositions can be moreover exploited for oxidant detection or for implementing potent contrast agents for magnetic resonance imaging. In this review, we present these different applications of rare-earth nanoparticles for biomolecule detection and imaging in vitro, in living cells or in small animals. We highlight how chemical composition tuning and surface functionalization lead to specific properties, which can be used for different imaging modalities. We discuss their performances for imaging in comparison with other probes and to what extent they could constitute a central tool in the future of molecular and cell biology.

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Section: Biochemical Applicationsmentioning

confidence: 99%

Section: Biochemical Applicationsmentioning

confidence: 99%

Biological Applications of Rare-Earth Based Nanoparticles

2011

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“…According to our previous optimizations, 5 mM glycine buffer pH 2 was chosen as the assay buffer. , The Eu(III)-doped polystyrene nanoparticles, 68 nm in diameter containing sulfite, carboxylic, and sulfate surface groups (p K a (−SO 3 H) 1.9, p K a (−COOH) 4.7, and p K a (−SO 4 H) −3), were commercially available. Due to these surface groups, the nanoparticles are negatively charged in the assay pH .…”

Section: Resultsmentioning

confidence: 99%

Luminometric Nanoparticle-Based Assay for High Sensitivity Detection of β-Amyloid Aggregation

et al. 2017

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A nanoparticle-based assay utilizing time-resolved luminescence resonance energy transfer (TR-LRET) was developed for the detection of β-amyloid aggregation. The assay is based on the competitive adsorption of the sample and the acceptor-labeled protein to donor europium(III) polystyrene nanoparticles. The performance of the assay was demonstrated by following the fibrillization of β-amyloid peptide 1-42 (Aβ) as a function of time and by comparing to the reference methods atomic force microscopy (AFM) and thioflavin T (ThT) assay. The fibrillization leads to reduced adsorption of Aβ to the nanoparticles increasing the TR-LRET signal. The investigated methods detected fibril formation with equal sensitivities. Eight potential fibrillization inhibitor compounds reported in the literature were tested and the results obtained with each method were compared. It was shown with AFM imaging that the inhibition of fibril formation was not complete with any of the compounds. The developed TR-LRET nanoparticle assay gave corresponding results with the AFM imaging. However, the ThT assay led to contradictory results, as low fluorescence signal was measured in the presence of all tested compounds suggesting inhibition of fibrillization. Our results suggest that the developed TR-LRET nanoparticle assay can be exploited for screening of potential β-amyloid aggregation inhibitors, whereas some of the tested compounds may be measured as false positive inhibitors with the much-utilized ThT assay.

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“…LLCs have also been incorporated into thin-film layers or NPs, either within the core-shell structure or bound to ligands on the NP surface, for a range of applications, including LRET-based bioassays, molecular imaging, and multiplex signal labels [369][370][371][372][373]. Song et al developed core-shell nanostructures aimed at improving the LRET efficiency of the NMs, which comprised a rhodaminefunctionalized silicon dioxide (SiO 2 ) core surrounded by a Tb chelate-modified SiO 2 shell [372].…”

Section: Luminescent Lanthanide Complexes and Doped Nano-/microparticlesmentioning

confidence: 99%

Materials for FRET Analysis: Beyond Traditional Dye–Dye Combinations

Sapsford

Wildt

Mariani

et al. 2013

FRET – Förster Resonance Energy Transfer

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The intrinsic sensitivity (r 6 dependence) of F€ orster (or fluorescence) resonance energy transfer (FRET) to nanoscale changes in the donor/acceptor separation distance has made FRET an invaluable biophysical tool in a variety of applications, ranging from studying the structure and conformation of proteins and nucleic acids to examining biomolecular interactions, including its use in in vitro and in vivo bioassays [1][2][3][4][5][6][7]. While the myriad of FRET configurations and techniques currently in use are covered throughout this book, here we focus primarily on the materials utilized as donor or acceptor probes in FRET rather than the process itself [3,5,8,9]. Our 2006 review paper on this topic serves as the foundation for this updated chapter [3]. The materials were divided into three main categories: organic materials that include "traditional" dye fluorophores, dark quenchers, polymers, and carbon nanomaterials (NMs); inorganic materials such as metal chelates, metal, and semiconductor nanocrystals; and fluorophores of biological origin such as fluorescent proteins (FPs), amino acids, and fluorescence generated from enzymatic bioluminescence (BL) and chemiluminescence (CL). These materials may function as FRET donors and/or acceptors, depending upon experimental design. Many of the new materials developed and/or new donor-acceptor probe combinations used address some of the inherent complications of more traditional FRET materials, including photobleaching, spectral cross talk, and direct excitation of the acceptor species, and examples of these will be highlighted and discussed throughout the chapter. Since the vast majority of FRET applications are biological in nature, they routinely involve some type of biomolecule labeling strategy, which ultimately plays a significant and fundamental role in the success and interpretation of the resulting FRET. Therefore, we begin the chapter with a brief discussion of the bioconjugation techniques commonly utilized for FRET and points to consider, followed by sections highlighting the current and emerging materials that are used, or have the potential to be used, in FRET applications.

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Sensitive Fluorometric Nanoparticle Assays for Cell Counting and Viability

Cited by 17 publications

References 27 publications

Biological Applications of Rare-Earth Based Nanoparticles

Biological Applications of Rare-Earth Based Nanoparticles

Luminometric Nanoparticle-Based Assay for High Sensitivity Detection of β-Amyloid Aggregation

Materials for FRET Analysis: Beyond Traditional Dye–Dye Combinations

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