Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

A Nanocrystal-based Ratiometric pH Sensor for Natural pH Ranges.

ABSTRACT: A ratiometric fluorescent pH sensor based on CdSe/CdZnS nanocrystal quantum dots (NCs) has been designed for biological pH ranges. The construct is formed from the conjugation of a pH dye (SNARF) to NCs coated with a poly(amido amine) (PAMAM) dendrimer. The sensor exhibits a well-resolved ratio response at pH values between 6 and 8 under linear or two-photon excitation, and in the presence of a 4% bovine serum albumin (BSA) solution.

SUBMITTER: Somers RC

PROVIDER: S-EPMC4582792 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

A Nanocrystal-based Ratiometric pH Sensor for Natural pH Ranges.

Somers Rebecca C RC Lanning Ryan M RM Snee Preston T PT Greytak Andrew B AB Jain Rakesh K RK Bawendi Moungi G MG Nocera Daniel G DG

Chemical science 20120101 10

A ratiometric fluorescent pH sensor based on CdSe/CdZnS nanocrystal quantum dots (NCs) has been designed for biological pH ranges. The construct is formed from the conjugation of a pH dye (SNARF) to NCs coated with a poly(amido amine) (PAMAM) dendrimer. The sensor exhibits a well-resolved ratio response at pH values between 6 and 8 under linear or two-photon excitation, and in the presence of a 4% bovine serum albumin (BSA) solution. ...[more]

PMID: 26413260

Similar Datasets

pHlash: a new genetically encoded and ratiometric luminescence sensor of intracellular pH.

Project description:We report the development of a genetically encodable and ratiometic pH probe named "pHlash" that utilizes Bioluminescence Resonance Energy Transfer (BRET) rather than fluorescence excitation. The pHlash sensor-composed of a donor luciferase that is genetically fused to a Venus fluorophore-exhibits pH dependence of its spectral emission in vitro. When expressed in either yeast or mammalian cells, pHlash reports basal pH and cytosolic acidification in vivo. Its spectral ratio response is H(+) specific; neither Ca(++), Mg(++), Na(+), nor K(+) changes the spectral form of its luminescence emission. Moreover, it can be used to image pH in single cells. This is the first BRET-based sensor of H(+) ions, and it should allow the approximation of pH in cytosolic and organellar compartments in applications where current pH probes are inadequate.

| S-EPMC3419163 | biostudies-literature

A polymer-based ratiometric intracellular glucose sensor.

Project description:The glucose metabolism level reflects cell proliferative status. A polymeric glucose ratiometric sensor comprising poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA) and poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMAETMA) was synthesized. Cellular internalization and glucose response of the polymer within HeLa cells were investigated.

| S-EPMC4093769 | biostudies-literature

Ratiometric detection of pH fluctuation in mitochondria with a new fluorescein/cyanine hybrid sensor.

Project description:The homeostasis of mitochondrial pH (pHm) is crucial in cell physiology. Developing small-molecular fluorescent sensors for the ratiometric detection of pHm fluctuation is highly demanded yet challenging. A ratiometric pH sensor, Mito-pH, was constructed by integrating a pH-sensitive FITC fluorophore with a pH-insensitive hemicyanine group. The hemicyanine group also acts as the mitochondria targeting group due to its lipophilic cationic nature. Besides its ability to target mitochondria, this sensor provides two ratiometric pH sensing modes, the dual excitation/dual emission mode (Dex/Dem) and dual excitation (Dex) mode, and its linear and reversible ratiometric response range from pH 6.15 to 8.38 makes this sensor suitable for the practical tracking of pHm fluctuation in live cells. With this sensor, stimulated pHm fluctuation has been successfully tracked in a ratiometric manner via both fluorescence imaging and flow cytometry.

| S-EPMC5490428 | biostudies-literature

A GFP-based ratiometric sensor for cellular methionine oxidation.

Project description:Methionine oxidation is a reversible post-translational protein modification, affecting protein function, and implicated in aging and degenerative diseases. The detection of accumulating methionine oxidation in living cells or organisms, however, has not been achieved. Here we introduce a genetically encoded probe for methionine oxidation (GEPMO), based on the super-folder green fluorescent protein (sfGFP), as a specific, versatile, and integrating sensor for methionine oxidation. Placed at amino-acid position 147 in an otherwise methionine-less sfGFP, the oxidation of this specific methionine to methionine sulfoxide results in a ratiometric fluorescence change when excited with ∼400 and ∼470 nm light. The strength and homogeneity of the sensor expression is suited for live-cell imaging as well as fluorescence-activated cell sorting (FACS) experiments using standard laser wavelengths (405/488 nm). Expressed in mammalian cells and also in S. cerevisiae, the sensor protein faithfully reports on the status of methionine oxidation in an integrating manner. Variants targeted to membranes and the mitochondria provide subcellular resolution of methionine oxidation, e.g. reporting on site-specific oxidation by illumination of endogenous protoporphyrin IX.

| S-EPMC9552927 | biostudies-literature

Ratiometric Bioluminescent Sensor Proteins Based on Intramolecular Split Luciferase Complementation.

Project description:Bioluminescent sensor proteins provide attractive tools for applications ranging from in vivo imaging to point-of-care testing. Here we introduce a new class of ratiometric bioluminescent sensor proteins that do not rely on direct modulation of BRET efficiency, but are based on competitive intramolecular complementation of split NanoLuc luciferase. Proof of concept for the feasibility of this sensor principle was provided by developing a blue-red light emitting sensor protein for the detection of anti-HIV1-p17 antibodies with a 500% change in emission ratio and a Kd of 10 pM. The new sensor design also improved the dynamic response of a sensor for the therapeutic antibody cetuximab 4-fold, allowing the direct quantification of this anti-EGFR antibody in undiluted blood plasma. The modular sensor architecture allows easy and systematic tuning of a sensor's dynamic range and should be generally applicable to allow rational engineering of bioluminescent sensor proteins.

| S-EPMC6350203 | biostudies-literature

Near infrared fluorescence-based bacteriophage particles for ratiometric pH imaging.

Project description:Fluorogenic imaging agents emitting in the near-infrared are becoming important research tools for disease investigation in vivo. Often pathophysiological states such as cancer and cystic fibrosis are associated with disruptions in acid/base homeostasis. The development of optical sensors for pH imaging would facilitate the investigation of these diseased conditions. In this report, the design and synthesis of a ratiometric near-infrared emitting probe for pH quantification is detailed. The pH-responsive probe is prepared by covalent attachment of pH-sensitive and pH-insensitive fluorophores to a bacteriophage particle scaffold. The pH-responsive cyanine dye, HCyC-646, used to construct the probe, has a fluorogenic pKa of 6.2, which is optimized for visualization of acidic pH often associated with tumor hypoxia and other diseased states. Incorporation of pH-insensitive reference dyes enables the ratiometric determination of pH independent of the probe concentration. With the pH-responsive construct, measurement of intracellular pH and accurate determination of pH through optically diffuse biological tissue is demonstrated.

| S-EPMC2705288 | biostudies-literature

Two-photon absorbing nanocrystal sensors for ratiometric detection of oxygen.

Project description:Two nanocrystal-osmium(II) polypyridyl (NC-Os(II)PP) conjugates have been designed to detect oxygen in biological environments. Polypyridines appended with a single free amine were linked with facility to a carboxylic acid functionality of a semiconductor NC overlayer to afford a biologically stable amide bond. The Os(II)PP complexes possess broad absorptions that extend into the red spectral region; this absorption feature makes them desirable acceptors of energy from NC donors. Fluorescence resonance energy transfer (FRET) from the NC to the Os(II)PP causes an enhanced Os(II)PP emission with a concomitant quenching of the NC emission. Owing to the large two-photon absorption cross-section of the NCs, FRET from the NC to the Os(II)PP can be established under two-photon excitation conditions. In this way, two-photon processes of metal polypyridyl complexes can be exploited for sensing. The emission of the NC is insensitive to oxygen, even at 1 atm, whereas excited states of both osmium complexes are quenched in the presence of oxygen. The NC emission may thus be used as an internal reference to correct for fluctuations in the photoluminescence intensity signal. These properties taken together establish NC-Os(II)PP conjugates as competent ratiometric, two-photon oxygen sensors for application in biological microenvironments.

| S-EPMC3340422 | biostudies-literature

Labeling and measuring stressed mitochondria using a PINK1-based ratiometric fluorescent sensor.

Project description:Mitochondria are essential organelles that carry out a number of pivotal metabolic processes and maintain cellular homeostasis. Mitochondrial dysfunction caused by various stresses is associated with many diseases such as type 2 diabetes, obesity, cancer, heart failure, neurodegenerative disorders, and aging. Therefore, it is important to understand the stimuli that induce mitochondrial stress. However, broad analysis of mitochondrial stress has not been carried out to date. Here, we present a set of fluorescent tools, called mito-Pain (mitochondrial PINK1 accumulation index), which enable the labeling of stressed mitochondria. Mito-Pain uses PTEN-induced putative kinase 1 (PINK1) stabilization on mitochondria and quantifies mitochondrial stress levels by comparison with PINK1-GFP, which is stabilized under mitochondrial stress, and RFP-Omp25, which is constitutively localized on mitochondria. To identify compounds that induce mitochondrial stress, we screened a library of 3374 compounds using mito-Pain and identified 57 compounds as mitochondrial stress inducers. Furthermore, we classified each compound into several categories based on mitochondrial response: depolarization, mitochondrial morphology, or Parkin recruitment. Parkin recruitment to mitochondria was often associated with mitochondrial depolarization and aggregation, suggesting that Parkin is recruited to heavily damaged mitochondria. In addition, many of the compounds led to various mitochondrial morphological changes, including fragmentation, aggregation, elongation, and swelling, with or without Parkin recruitment or mitochondrial depolarization. We also found that several compounds induced an ectopic response of Parkin, leading to the formation of cytosolic puncta dependent on PINK1. Thus, mito-Pain enables the detection of stressed mitochondria under a wide variety of conditions and provides insights into mitochondrial quality control systems.

| S-EPMC8560995 | biostudies-literature

Nanocrystal Encapsulation, Release and Application Based on pH-Sensitive Covalent Dynamic Hyperbranched Polymers.

Project description:A new strategy for nanocrystal encapsulation, release and application based on pH-sensitive covalent dynamic hyperbranched polymers is described. The covalent dynamic hyperbranched polymers, with multi-arm hydrophobic chains and a hydrophilic hyperbranched poly(amidoamine) (HPAMAM) core connected with pH-sensitive imine bonds (HPAMAM-DA), could encapsulate CdTe quantum dots (QDs) and Au nanoparticles (NPs). Benefiting from its pH response property, CdTe QDs and Au NPs encapsulated by HPAMAM-DA could be released to aqueous phase after imine hydrolysis. The released CdTe/HPAMAM and Au/HPAMAM nanocomposites exhibited excellent biological imaging behavior and high catalytic activities on p-nitrophenol hydrogenation, respectively.

| S-EPMC6960846 | biostudies-literature

FLIM-Based Intracellular and Extracellular pH Measurements Using Genetically Encoded pH Sensor.

Project description:The determination of pH in live cells and tissues is of high importance in physiology and cell biology. In this report, we outline the process of the creation of SypHerExtra, a genetically encoded fluorescent sensor that is capable of measuring extracellular media pH in a mildly alkaline range. SypHerExtra is a protein created by fusing the previously described pH sensor SypHer3s with the neurexin transmembrane domain that targets its expression to the cytoplasmic membrane. We showed that with excitation at 445 nm, the fluorescence lifetime of both SypHer3s and SypHerExtra strongly depend on pH. Using FLIM microscopy in live eukaryotic cells, we demonstrated that SypHerExtra can be successfully used to determine extracellular pH, while SypHer3s can be applied to measure intracellular pH. Thus, these two sensors are suitable for quantitative measurements using the FLIM method, to determine intracellular and extracellular pH in a range from pH 7.5 to 9.5 in different biological systems.

| S-EPMC8468847 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data