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.
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.
Biotium ships all antibodies (primary, secondary and conjugates) at room temperature. We guarantee their quality and performance under these conditions based upon our stability testing. Antibodies were subjected to accelerated stability testing by storing them at various temperatures (4°C, room temperature, or 37°C) for 1 week to mimic simulated shipping conditions and tested in immunostaining experiments. All antibodies showed the expected brightness and specificity, even after storage at sub-optimal temperatures.
In line with our goal to be more environmentally friendly by reducing the use of excess packaging, and lowering shipping costs for our customers, products that have passed our stability testing are shipped at room temperature.
Once you have received the antibody vial, please follow the long-term storage instructions on the product information (PI) sheet.
DAPI (4′,6-Diamidino-2-Phenylindole, dihydrochloride) is a popular blue DNA dye that is used as a nuclear counterstain in fluorescence microscopy, chromosome staining, and flow cytometry. The dye binds to the minor groove of dsDNA with approximately 20-fold fluorescence enhancement, with higher affinity for A-T rich regions.
Classic blue nuclear counterstain for fixed cells
Available as a powder or solution
Can be used at higher concentrations to stain live cells
λEx/λEm (with DNA) = 358/461 nm
Store at 4°C and protect from light, especially in solution
DAPI as a dilactate powder is more water soluble than the dihydrochloride salt, and therefore a better choice for preparing stock solutions in water. If mounting media will be used, we also offer anti-fade mounting media containing DAPI, in both hardset and wetset formulations. Having trouble with your experiments? See our section on troubleshooting tips for fluorescent staining.
(10 mg/mL in water)
Find the Right Nuclear Stain for Your Application
DAPI can be used to stain mammalian cells as well as gram-positive and gram-negative bacteria. In yeast, the staining is weak and not nuclear. DAPI is less membrane permeant than Hoechst, and is typically used to stain fixed cells. On the other hand, Hoechst dyes are membrane-permeant and more often used for live or fixed cell staining and cell cycle analysis. While Hoechst and DAPI show less cytotoxicity than intercalating DNA dyes, they bind DNA in living cells and are potentially hazardous. DAPI and Hoechst undergo photoconversion by UV excitation to form green fluorescent dyes, which can lead to artifacts in multi-color imaging. See our Tech Tip Avoiding Artifacts from UV Photoconversion of DAPI and Hoechst for more information.
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.