Most of our products are stable at room temperature for many days, so in all likelihood the product will still work just fine. To be on the safe side, we recommend performing a small scale positive control experiment to confirm that the product still works for your application before processing a large number of samples or precious samples.
One exception that we are aware of is GelGreen™, which is more sensitive to light exposure than most of our other fluorescent dyes. If GelGreen™ is exposed to ambient light for a prolonged period of time (days to weeks), its color will change from dark orange to brick red. If this occurs, the GelGreen will no longer work for gel staining.
The guaranteed shelf life from date of receipt for bioscience kits is listed on the product information sheet. Some kits have an expiration date printed on the kit box label, this is the guaranteed shelf life date calculated from the day that the product shipped from our facility. Kits often are functional for significantly longer than the guaranteed shelf life. If you have an older kit in storage that you wish to use, we recommend performing a small scale positive control experiment to confirm that the kit still works for your application before processing a large number of samples or precious samples.
Antibodies and other conjugates
The guaranteed shelf life from date of receipt for antibodies and conjugates is listed on the product information sheet. Antibodies and other conjugates often are functional for significantly longer than the guaranteed shelf life. If you have an older conjugate in storage that you wish to use, we recommend performing a small scale positive control experiment to confirm that the product still works for your application before processing a large number of samples or precious samples.
For lyophilized antibodies, we recommend reconstituting the antibody with glycerol and antimicrobial preservative like sodium azide for the longest shelf life (note that sodium azide is not compatible with HRP-conjugates).
Chemicals, dyes, and gel stains
Biotium guarantees the stability of chemicals, dyes, and gel stains for at least a year from the date you receive the product. However, the majority of these products are highly stable for many years, as long as they are stored as recommended. Storage conditions can be found on the product information sheet or product safety and data sheet, material safety data sheet, and on the product label. Fluorescent compounds should be protected from light for long term storage.
If you have a Biotium compound that has been in storage for longer than one year that you wish to use, we recommend performing a small scale positive control experiment to confirm that the compound still works for your application before processing a large number of samples or precious samples.
Expiration date based on date of manufacture (DOM)
If your institution requires you to document expiration date based on date of manufacture for reagents, please contact firstname.lastname@example.org for assistance.
Chemical products with special stability considerations:
Ester compounds include the following:
• Succinimidyl esters (SE, also known as NHS esters), such as our amine-reactive dyes
• Acetoxymethyl esters (AM esters) such as our membrane-permeable ion indicator dyes
• Diacetate-modified dyes, like ViaFluor™ 405, CFDA, and CFDA-SE cell viability/cell proliferation dyes
Ester dyes are stable in solid form as long as they are protected from light and moisture. Esters are not stable in aqueous solution. Concentrated stock solutions should be prepared in anhydrous DMSO (see Biotium catalog no. 90082). Stock solutions in anhydrous DMSO can be stored desiccated at -20°C for one month or longer. Esters should be diluted in aqueous solution immediately before use. Succinimidyl esters (SE) should be dissolved in a solution that is free of amine-containing compounds like Tris, glycine, or protein, which will react with the SE functional group. AM esters and diacetate compounds should be dissolved in a solution that is free of serum, because serum could contain esterases that would hydrolyze the compound.
A note on CF® Dye succinimidyl ester stability
Succinimidyl esters (SE) are generally susceptible to hydrolysis, which can result in lower labeling efficiency. Many commercially available fluorescent dyes used for life science research are heavily sulfonated dyes which makes them particularly hygroscopic, worsening the hydrolysis problem. In addition, for several commercially available SE reactive dyes, the SE group is derived from an aromatic carboxylic acid, while the SE group in all of Biotium’s CF® Dyes is prepared from an aliphatic carboxylic acid. This structural difference reduces the susceptibility of CF® Dye SE reactive groups to hydrolysis, resulting in relatively stable reactive dyes with consistently higher labeling efficiency compared to other SE derivatives of other fluorescent dyes.
Maleimides, MTS and thiosulfate dyes
Like the succinimidyl ester dyes, these dyes are also susceptible to hydrolysis, although generally to a much lower degree. Thus, for long term storage, anhydrous DMSO is recommended for making stock solutions.
Other reactive dyes
Amines, aminooxy (also known as oxylamine), hydrazide, azide, alkyne, BCN, and tyramide reactive dyes, as well as dye free acids, are generally stable in aqueous solution when stored at -20°C for 6-12 months or longer, as long as no compounds are present that may react with the dye’s functional group. See the product information sheets for specific reactive dyes more information.
Coelenterazines and D-luciferin
Coelenterazines are stable in solid form when stored as recommended; they are not stable in aqueous solution. Concentrated coelenterazine stock solutions (typically 1-100 mg/mL) should be prepared in ethanol or methanol; do not use DMSO or DMF to dissolve coelenterazines, because these solvents will oxidize the compounds. Ethanol or methanol stocks of coelenterazine can be stored at -20°C or below for six months or longer; alcohol stocks may evaporate during storage, so use tightly sealing screw cap vials and wrap the vials with Parafilm for long term storage. Propylene glycol also can be used as a solvent to minimize evaporation. If the solvent evaporates, the coelenterazine will still be present in the vial, so note the volume in the vial prior to storage so that you can adjust the solvent volume to correct for evaporation if needed. Prepare working solutions in aqueous buffers immediately before use. Coelenterazines are stable for up to five hours in aqueous solution.
Aquaphile™ coelenterazines are water soluble formulations of coelenterazines. They are stable in solid form when stored as recommended. Aquaphile™ coelenterazines should be dissolved in aqueous solution immediately before use. They are stable for up to five hours in aqueous solution.
Note that coelenterazines are predominantly yellow solids, but may contain dark red or brown flecks. This does not affect product stability or performance. If your coelenterazine is uniformly brown, then it is oxidized and needs to be replaced.
D-luciferin is stable in solid form and as a concentrated stock solution when stored as recommended; it is not stable at dilute working concentrations in aqueous solution. Prepare concentrated D-luciferin stock solutions (typically 1-100 mg/mL) in water, and store in aliquots at -20°C or below for six months or longer. Prepare working solutions immediately before use.
Most of our products are stable at room temperature for many days, but we recommend storage at 4°C or -20°C to prolong shelf life. In the case of many of our aqueous dye solutions, the compounds are very stable at room temperature, but we recommend cold storage to prevent the growth of mold or other microbes over time. Therefore, to save on shipping costs, products with recommended storage at 4°C or -20°C may ship at ambient temperature or with an ice pack. These products may thaw without affecting product performance. When you receive the product, place it under the recommended storage conditions.
Some products are shipped with blue ice packs as an extra precaution against high temperatures. The blue ice packs may be thawed upon arrival without affecting product performance.
Products with recommended storage at ultra low temperature (-70°C) that also ship on dry ice should arrive frozen. If a product you received was shipped on dry ice and thawed during transit, please contact customer service at email@example.com.
NucSpot® Nuclear Stains are cell membrane-impermeant, nuclear-specific counterstains available in a variety of colors from green to near-infrared (near-IR).
Nuclear-specific counterstains for fixed cells
Selectively stains dead cells in live culture
No wash required
Options for cell cycle profiling by flow cytometry in fixed/permeabilized cells
Color options for FITC, Cy®3, PE, Texas Red®, Cy®5, APC, Cy®5.5, and Cy®7 channels
NucSpot® Stains have minimal fluorescence until they bind to DNA and can be used for no-wash nuclear staining. Unlike other nucleic acid dyes such as propidium iodide (PI), TOTO®, TO-PRO®, and similar dyes that stain both the nucleus and cytoplasm, NucSpot® Nuclear Stains selectively stain the nucleus in fixed and permeabilized cells without the need for RNase treatment.
NucSpot® Nuclear Stains also can be used for selective staining of dead cells in unfixed cell cultures for analysis by flow cytometry or fluorescence imaging. Several of the dyes can be continuously incubated with cells for multi-day imaging. NucSpot® 470 and NucSpot® Far-Red can be used for DNA content analysis of cell cycle by flow cytometry in fixed and permeabilized cells without requiring RNase treatment, unlike propidium iodide.
* May show crosstalk in lower wavelength detection channels. Perform single-stain controls before combining with other probes.
† NucSpot® Far-Red is designed for flow cytometry optical systems and is not recommended for fluorescence microscopy.
Find the Right Dye for Your Application
Stain Dead Cells in Live Cultures
NucSpot® Nuclear Stains offer improved photostability over commonly used cyanine-based nuclear stains. The figure below shows how NucSpot® 650/665 is significantly more photostable than Thiazole Red Homodimer (TOTO® -3).
NucSpot® 470 has green fluorescence that can be imaged using standard settings for FITC. With an excitation maximum around 460 nm, it is an excellent match for instruments with blue LED excitation sources as well. It can be used for DNA content analysis of cell cycle by flow cytometry in fixed and permeabilized cells without requiring RNase treatment, unlike propidium iodide. NucSpot® 470 can also be used for nuclear staining of dead or permeabilized yeast. In gram-negative bacteria it selectively stains dead cells, while in gram-positive bacteria it may stain live cells.
NucSpot® 500/515 is a green fluorescent nuclear stain for the FITC channel. In addition to bright nuclear counterstaining of fixed cells, it can also be used for multi-day live/dead staining of mammalian cells in culture.
NucSpot® 555/570 and NucSpot® 568/580 have orange and visible red fluorescence, respectively, and are nuclear-specific alternatives to PI and similar dyes.
NucSpot® 594/615 has deep red fluorescence for the Texas Red® channel.
NucSpot® 650/665 has far-red fluorescence with superior nuclear specificity compared to first-generation far-red nuclear stains such as RedDot™2 and Draq7™.
NucSpot® 680/700 and NucSpot® 750/780 are spectrally unique DNA stains for far-red and near-IR detection.
Biotium also offers NucSpot® Far-Red, a flow cytometry stain developed as an improved alternative to 7-AAD. It shows less bleed-through fluorescence in the PE-Texas Red® channel compared to 7-AAD and is ideal for selective detection of dead cells or DNA content analysis by flow cytometry without RNase treatment.
Learn more about our full selection of Cellular Stains for the nucleus and other organelles.
TOTO and TO-PRO are registered trademarks of Thermo Fisher Scientific; Draq is a trademark of BioStatus Ltd; CY is a registered trademark of Cytiva.
A revolutionary antifade mounting medium optimally formulated for preserving fluorescence of our CF® dyes and other fluorochromes. EverBrite™ Hardset mounting medium hardens at room temperature completely in 24 hours.