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.
NucView® Caspase-3 Substrates can be added to the cells at the start of the experiment or at the end. A major advantage of NucView® Caspase-3 Substrates compared to other apoptosis assays is that it can be used to monitor capase-3 activity in real time.
NucView® 530 Caspase-3 Substrate, 1 mM in PBS, provides a convenient tool for detecting apoptosis in intact cells based on caspase-3/7 activity using either confocal microscopy or flow cytometry.
In contrast to other fluorogenic caspase substrates or fluorescent caspase inhibitor based (FLICA) assays, NucView® caspase-3 substrates can be used to detect caspase-3/7 activity within individual intact cells without inhibiting apoptosis progression. NucView® substrates consist of a fluorogenic DNA dye coupled to the caspase-3/7 DEVD recognition sequence. The substrate, which is initially non-fluorescent, penetrates the plasma membrane and enters the cytoplasm. In apoptotic cells, caspase-3/7 cleaves the substrate, releasing the high-affinity DNA dye, which migrates to the cell nucleus and stains DNA with fluorescence. Thus, NucView® Caspase-3 Substrates are bifunctional, allowing detection of caspase-3/7 activity and visualization of morphological changes in the nucleus during apoptosis. The staining is also formaldehyde-fixable.
NucView® 530 Caspase-3 Substrate stains apoptotic cell nuclei with orange fluorescence (Ex/Em 528/563 nm, Figure 1), for detection in the Cy®3 channel by fluorescence microscopy (Figure 2) or the PE channel by flow cytometry (Figure 3). NucView® 530 can be used for multi-color imaging with blue, green, or far-red fluorescent probes. Note that when excited by the 488 nm laser line, NucView® 530 also fluoresces in the FITC channel, and therefore cannot be analyzed together with green probes by flow cytometry.
NucView® 530 Caspase-3 Substrate is available as a 1 mM solution in DMSO (catalog no. 10406) or PBS (phosphate-buffered saline). The substrate in PBS is formulated for use in cells that are sensitive to DMSO toxicity. In non-DMSO sensitive cell types, adding DMSO during the substrate incubation may enhance NucView® 530 staining.
The CF® dye TUNEL Assay Apoptosis Detection Kit employs dUTP conjugated to the exceptionally bright and photostable fluorescent dyes, for single step fluorescent TUNEL labeling of fixed cells or tissues for analysis by fluorescence microscopy or flow cytometry.