TrueBlack® Lipofuscin Autofluorescence Quencher, 20X in DMF, is a new reagent for quenching lipofuscin autofluorescence in tissue sections for immunofluorescence staining. It can also help reduce autofluorescence from other sources like extracellular matrix.
The storage conditions that a Biotium label recommends are deliberately conservative. Long term storage at low temperatures usually will increase the time that the product will remain within specification, unless specific instructions otherwise are provided (such as “do not refrigerate” or “do not freeze”).
Biotium labels and product information sheets may show a specific temperature for long term storage, or a temperature range that is adequate for long term storage. For all products, the implied range is as follows for the following storage conditions:
For Biotium products where the label indicates room temperature or RT, this implies storage in ambient conditions between 20°C and 30°C.
For Biotium products where the label indicates 4°C, this implies storage in a refrigerator that is between 2°C and 8°C.
For Biotium products where the label indicates -20°C, this implies storage in a freezer that is between -35°C and -5°C.
Ultra Low Temperature Freezer
For Biotium products where the label indicates -70°C, this implies storage in an ultra low-temperature (ULT) freezer that is below -60°C.
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 are generally susceptible to hydrolysis, which can result in lower labeling efficiency. Heavily sulfonated dyes, such as the Alexa Fluor® dyes, DyLight® dyes and IRDyes® are particularly hygroscopic, worsening the hydrolysis problem. For example, the percent of active Alexa Fluor® 488 succinimidyl ester (SE) could be well below 50% by the time of application (according to the manufacturer’s product datasheet). In a number of Alexa Fluor® SE reactive dyes, the SE group is derived from an aromatic carboxylic acid, while in all of Biotium’s CF™ dyes the SE group 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.
Many of our solid compounds are packaged by lyophilization, in which case they usually do not appear as fluffy powders, but form a film or coating on the sides of the vial. Simply add the appropriate volume of the recommended solvent to the vial to make the desired concentration stock solution, and swirl or gently vortex to mix. Make sure the solvent comes in contact with the inside walls of the vial to fully recover the product.
Reduces autofluorescence from non-lipofuscin sources
Doesn’t cause high background, unlike Sudan Black B
Can be used before or after immunofluorescence staining
Clears the way for fluorescence imaging of human and aged animal tissues
TrueBlack® Lipofuscin Autofluorescence Quencher, 20X in DMF, is a new reagent for quenching lipofuscin autofluorescence in tissue sections for immunofluorescence staining. Lipofuscin consists of highly autofluorescent granules of oxidized proteins and lipids that build up in the lysosomes of aging cells. Lipofuscin granules fluoresce brightly in all channels used for fluorescence microscopy, and accumulate in a variety of cell and tissue types with age. Consequently, imaging of specific immunofluorescence signal in certain adult human tissues or aged animal tissues can be virtually impossible unless methods are employed to quench or mask lipofuscin fluorescence.
Traditionally, Sudan Black B has been used to quench lipofuscin autofluorescence by incubating tissue sections with the dye after immunofluorescence staining. However, while it masks the autofluorescence from lipofuscin, Sudan Black B also introduces uniform non-specific background fluorescence in the red and far-red channels (Fig. 1), limiting the use of fluorescent dyes in those wavelengths. Now Biotium has developed TrueBlack® as a superior alternative to Sudan Black B. TrueBlack® quenches lipofuscin fluorescence with far less increase in red/far-red background fluorescence (Fig. 1). TrueBlack® treatment can be performed before or after immunostaining. It is rapid, simple, and has minimal effect on signal from fluorescent antibodies or nuclear counterstains, thus preserving the signal-to-noise ratio of the immunostaining (Figs. 2-3).
TrueBlack® effectively eliminates lipofuscin autofluorescence in tissues like human and mouse brain and retina (see Figs. 1-3 and TrueBlack® References). TrueBlack® also can reduce autofluorescence from other sources, such as collagen, elastin, red blood cells, and general background fluorescence. It is not as effective at quenching these sources of autofluorescence as it is for lipofuscin, but it can improve background in human and non-human tissue types (Figs. 4-5). TrueBlack® also has been used to quench background fluorescence on polycarbonate filters used as cell supports for imaging cytometry.
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.
CoverGrip™ Coverslip Sealant is the first product specifically designed for sealing the edges of wet-mounted coverslips for fluorescence microscopy. Unlike nail polish, CoverGrip™ contains no ingredients that can leach into aqueous mounting medium and affect specimen fluorescence.
RedDot™2 is a far-red cell membrane-impermeable nuclear dye similar to Draq7™, with excitation and emission at 665/695 nm. The dye is ideal for specifically staining the nuclei of dead cells with minimal cytoplasmic RNA staining.
The SuperHT PAP Pen draws a water repellent circle around slide mounted tissue and prevents the waste of valuable reagents by keeping the liquid pooled in a single droplet. Available in two sizes, regular (4 mm tip) and mini (2.5 mm tip).
Drop-n-Stain™ CF® dye goat anti-mouse IgG (H+L) is provided in a convenient dropper bottle for easy dispensing without pipetting. To minimize cross-reactivity, the antibody has been adsorbed against bovine, horse, human, rabbit and swine serum.