Invitrogen™ FM™ 1-43FX, fixable analog of FM™ 1-43 membrane stain

Catalog No.	Quantity
F35355	10 x 100 μg

Catalog No. F35355 Supplier Invitrogen™ Supplier No. F35355

Description

Fixable analog of FM 1-43 membrane stain

FM 1-43FX membrane probe is an FM 1-43 membrane probe analog that has been modified to contain an aliphatic amine. That modification makes the probe fixable with aldehyde-based fixatives (formaldehyde, glutaraldehyde, etc.). FM 1-43 membrane probe is widely used both for identifying actively firing neurons and for investigating the mechanisms of activity-dependent vesicle cycling. Unmodified FM 1-43 membrane probe is available as 1mg in a single vial (T-3163) and as 1mg packaged into 10 vials, each containing 100μg (T-35356).

Cell Analysis, Cell Structure, Cell Tracing & Tracking, Cell Viability, Proliferation & Function, Endocytosis, Exocytosis & Phagocytosis, General Cell Tracing, Microbial Tracking, Neuronal Tracing, Plasma Membrane

Order Info

Shipping Condition: Room Temperature

Specifications

• Color: Orange
• Content And Storage: Store at room temperature and protect from light.
• For Use With (Equipment): Fluorescence Microscope
• Quantity: 10 x 100 μg
• Detection Method: Fluorescence
• Product Line: FM
• Shipping Condition: Room Temperature
• Label Type: Fluorescent Dye
• Product Type: Membrane Stain
• SubCellular Localization: Plasma Membrane

Frequently Asked Questions (FAQs)

I want to study endosomes trafficking using FM 4-64. Will the label be retained after fixation? And can I label already-fixed cells?

No. For that you would need the FM 4-64FX version. The non-FX version will not be retained upon fixation, leading to loss of much of the stain and an increase in background. The FX version will be retained using an aldehyde-based fixative. Cells that are already fixed will be stained throughout the cell and the signal will not be localized; it is recommended to stain live cells and then fix.

I want to study endosome trafficking using FM 4-64 dye. Will the label be retained after fixation? And can I label cells that have already been fixed?

No. For that, you would need the FM 4-64FX version. The non-FX version will be lost, leading to loss of much of the specific label and a vast increase in background labeling. The FX version will be fixed in place with formaldehyde. Cells that have been fixed already will not label correctly, so you will need to label the cells live and then fix.

The product sheet for FM 1-43 Dye states that the maximum for excitation is 510 nm and emissions is 626 nm, but the spectrum on the product page shows a peak at 470 nm and 580 nm. Can you clarify what the excitation and emission maxima is for this dye?

FM lipophilic styryl dyes are known to shift their spectral properties upon binding to membranes. These dyes exhibit an appreciable solvent and environmental dependency in both free and membrane-bound forms. The emissions of the membrane-bound dye shifts to a shorter wavelength compared to the emission in the solvent.

In solvent, FM 1-43 Dye (Cat. Nos. T35356, T3163, F35355, F10317) absorbs in the range of fluorescein (~490 nm) and initially emits at around 626-636 nm. However, upon membrane integration, it exhibits emission in the 565-590 nm range. Because this dye exhibits a large Stokes shift, it does not perfectly fit into a green or orange fluorophore profile, but is rather a yellow-fluorescent dye, and may require a long-pass emission filter.

Note: FM 1-43 Dye is often used with typical fluorescein or GFP optical filter sets for biological imaging but is poorly excited through tetramethylrhodamine filters.

For Research Use Only. Not for use in diagnostic procedures.