Shop All Cellular Sensors & Indicators

SNARF™-4F 5-(and-6)-Carboxylic Acid, Acetoxymethyl Ester, Acetate - Special Packaging (Invitrogen™)

The cell-permeant ratiometric pH indicator SNARF®-4F 5-(and-6)-carboxylic acid, acetoxymethyl ester, acetate (pKa of ~6.4) exhibits a significant pH-dependent emission shift from yellow-orange to deep red fluorescence under acidic and basic conditions, respectively. This pH dependence allows the ratio of the fluorescence intensities from the dye at two emission wavelengths - typically 580 nm and 640 nm - to be used for quantitative determinations of pH.

Fura-4F, Pentapotassium Salt, cell impermeant (Invitrogen™)

Fura-4F, pentapotassium salt is an intracellular calcium indicator similar to fura-2 but with response range shifted for detection of higher Ca2+ concentrations. This water-soluble salt form is useful for intracellular loading by microinjection, infusion from patch pipette or uptake induced by our Influx pinocytic cell-loading reagent (I-14402).

BCECF, AM (2',7'-Bis-(2-Carboxyethyl)-5-(and-6)-Carboxyfluorescein, Acetoxymethyl Ester) (Invitrogen™)

BCECF, AM is ideal for measuring changes in the cytosolic pH of most cells, because it is a cell-permeant, dual-excitation ratiometric pH indicator with a pKa of ~6.98. Intracellular pH measurements with BCECF are made by determining the pH-dependent ratio of emission intensity (detected at 535 nm) when the dye is excited at ~490 nm versus the emission intensity when excited at its isobestic point of ~440 nm.

SNARF™-5F 5-(and-6)-Carboxylic Acid (Invitrogen™)

The cell-impermeant ratiometric pH indicator SNARF®-5F 5-(and-6)-carboxylic acid (pKa of ~7.2) exhibits a significant pH-dependent emission shift from yellow-orange to deep red fluorescence under acidic and basic conditions, respectively. This pH dependence allows the ratio of the fluorescence intensities from the dye at two emission wavelengths - typically 580 nm and 640 nm - to be used for quantitative determinations of pH.

Carboxy-DCFDA (5-(and-6)-Carboxy-2',7'-Dichlorofluorescein Diacetate), mixed isomers (Invitrogen™)

Carboxy-DCFDA can passively diffuse into cells and is colorless and nonfluorescent until the acetate groups are cleaved by intracellular esterases to yield the fluorescent fluorophore, 5-(and-6)-carboxy-2',7' -dichlorofluorescein. With a pKa of 4.8, this dye can be used as an acidic pH sensor.

BODIPY™ 665/676 (Lipid Peroxidation Sensor) (Invitrogen™)

Lipid peroxidation can be detected with the lipophilic probe, BODIPY® 665/676 dye. This probe exhibits a change in fluorescence after interaction with peroxyl radicals.

Total Reactive Oxygen Species (ROS) Assay Kit 520 nm (Invitrogen™)

The Total Reactive Oxygen Species (ROS) Assay Kit 520 nm contains the necessary regent and buffer for identifying ROS in cells by flow cytometry in the FITC channel. Reactive oxygen species are chemically reactive oxygen-containing molecules that are generated as a natural byproduct of the oxygen metabolism. ROS are constantly generated and eliminated under normal physiologic conditions and have important functions in cell signaling, homeostasis, and clearance of microbial infections. During times of environmental stress such as exposure to UV or heat, or during infection, ROS levels can increase dramatically leading to oxidative stress. Oxidative stress can result in damage to cellular proteins, lipids, and DNA, and has been linked to cardiovascular disease, cancer, diabetes, inflammation, and aging. Examples of ROS include superoxide ions and peroxides.

Reported Application
Flow Cytometric Analysis

Fura-4F, AM, cell permeant - Special Packaging (Invitrogen™)

Fura-4F AM is an intracellular calcium indicator similar to fura-2 but with a response range shifted to detect higher Ca2+ concentrations. This acetoxymethyl (AM) ester derivative is useful for noninvasive intracellular loading. This sku can be used in place of the recently discontinued fura 5F AM, F14177. Ex/Ems are identical, and more importantly the Kd's(Ca2+) µM are very similar: 0.40 for fura-5F AM vs 0.77 for fura-4F AM.

Oregon Green™ 488 BAPTA-1, AM, cell permeant - Special Packaging (Invitrogen™)

Labeled calcium indicators are molecules that exhibit an increase in fluorescence upon binding Ca2+. They have uses in many calcium signaling investigations, including measuring intracellular Ca2+, following Ca2+ influx and release, and multiphoton excitation imaging of Ca2+ in living tissues. Cells may be loaded with the AM ester forms of these calcium indicators by adding the dissolved indicator directly to dishes containing cultured cells. The fluorescence signal from these cells is generally measured using fluorescence microscopy, fluorescence microplate assays, or flow cytometry.

Calcium Indicator (AM Ester) Specifications:
• Label (Ex/Em): Oregon Green® 488 BAPTA-1 (494/523 nm)
• Fluorescence intensity increase upon binding Ca2+ : ~14 fold
• Exhibit fluorescence increase upon binding Ca2+ with little shift in wavelength


Spectral Characteristics of Molecular Probes® Calcium Indicators
These probes are excited by visible light, and because the energy required for excitation is low, the potential for cellular photodamage is reduced. Commonly used laser-based instruments (i.e., confocal laser scanning microscopes) are able to efficiently excite these indicators, and their emissions are in regions of the spectrum where cellular autofluorescence and scattering backgrounds are often less of a problem.

More Choices for Fluorescent Calcium Indicators
We offer a large selection of Molecular Probes® calcium indicators for use in various experimental scenarios, for example dextran versions for reduced leakage and compartmentalization and BAPTA conjugates for detecting high-amplitude calcium transients. For more information, review Fluorescent Ca2+ Indicators Excited with Visible Light—Section 19.3 in the Molecular Probes® Handbook.

For UV-excitable Ca2+ indicators, protein-based Ca2+ indicators, conjugates of Ca2+ indicators, and for fluorescence-based indicators of other metal ions (i.e., Mg2+, Zn2+) review Indicators for Ca2+, Mg2+, Zn2+ and Other Metal Ions—Chapter 19 in the Molecular Probes® Handbook.

For Research Use Only. Not intended for animal or human therapeutic or diagnostic use.

Fluo-3, AM, cell permeant (Invitrogen™)

Labeled calcium indicators are molecules that exhibit an increase in fluorescence upon binding Ca2+. Fluo-3 has been used to image the spatial dynamics of Ca2+ signaling, in flow cytometry experiments involving photoactivation of caged chelators, second messengers, and neurotransmitters, and for cell-based pharmacological screening. Fluo-4 is an analog of fluo-3 with the two chlorine substituents replaced by fluorines, which results in increased fluorescence excitation at 488 nm and consequently higher fluorescence signal levels. Cells may be loaded with the AM ester forms of these calcium indicators by adding the dissolved indicator directly to dishes containing cultured cells. These indicators are useful for fluorescence and confocal microscopy, flow cytometry, and microplate screening applications.

Calcium Indicator (AM Ester) Specifications:
• Label (Ex/Em of Ca2+–bound form): Fluo-3 (506/526 nm)
• Fluorescence intensity increase upon binding Ca2+: >100 fold
• Kd for Ca2+ in buffer: ~335 nM
• Exhibit fluorescence increase upon binding Ca2+ with little shift in wavelength


Using TPEN to Control Heavy Metal Cations
In addition, BAPTA-based indicators such as these bind various heavy metal cations (e.g., Mn2+, Zn2+, Pb2+) with substantially higher affinity than Ca2+. Perturbations to calcium measurements caused by presence of these ions can be controlled using the heavy metal-selective chelator TPEN.

More Choices for Fluorescent Calcium Indicators
We offer a large selection of Molecular Probes® calcium indicators for use in various experimental scenarios. For more information, review Fluorescent Ca2+ Indicators Excited with Visible Light—Section 19.3 in the Molecular Probes® Handbook.

For UV-excitable Ca2+ indicators, protein-based Ca2+ indicators, conjugates of Ca2+ indicators, and for fluorescence-based indicators of other metal ions (i.e., Mg2+, Zn2+) review Indicators for Ca2+, Mg2+, Zn2+ and Other Metal Ions—Chapter 19 in the Molecular Probes® Handbook.

For Research Use Only. Not for human or animal therapeutic or diagnostic use.

Resazurin, Sodium Salt (Invitrogen™)

The non-fluorescent resazurin can be used as a fluorogenic oxidation-reduction indicator in a variety of cells, including bacteria, yeast and eukaryotes by flow cytometry, fluorescence microscopy and high-throughput screening. The red-fluorescent product, resorufin exhibits absorption/emission maxima ~575/585 nm.

SNARF™-5F 5-(and-6)-Carboxylic Acid, Acetoxymethyl Ester, Acetate - Special Packaging (Invitrogen™)

The cell-permeant ratiometric pH indicator SNARF®-5F 5-(and-6)-carboxylic acid, acetoxymethyl ester, acetate (pKa of ~7.2) exhibits a significant pH-dependent emission shift from yellow-orange to deep red fluorescence under acidic and basic conditions, respectively. This pH dependence allows the ratio of the fluorescence intensities from the dye at two emission wavelengths - typically 580 nm and 640 nm - to be used for quantitative determinations of pH.

Mag-Fura-2, AM, cell permeant (Invitrogen™)

Mag-fura-2, AM is an intracellular magnesium indicator that is ratiometric and UV light-excitable. This acetoxymethyl (AM) ester form is useful for noninvasive intracellular loading and is also available in special packaging (M1292). A Cell-impermeant tetrapotassium (M1290) salt form of the dye is available.

Fura-2 Calcium Imaging Calibration Kit (Zero to 10 mM CaEGTA, 50 µM Fura-2) (Invitrogen™)

The Fura-2 Calcium Imaging Calibration Kit is designed to facilitate rapid calibration and standardization of digital imaging microscopes. The kit contains 11 pre-diluted buffers supplemented with 50 µM fura-2 (F-1200) as well as 15 µm—diameter microspheres.

Fura-2, AM, FluoroPure™ grade - Special Packaging (Invitrogen™)

Because it is manufactured at our ISO 9001—certified facilities in Eugene, Oregon, we can guarantee that FluoroPure grade Fura-2 AM is greater than or equal to 98% pure by HPLC.