How long should I dialyze with the Slide-A-Lyzer Cassette?
Typically, one should dialyze for one hour at room temperature three times in dialysate that is about 300 times the sample volume. If required, dialysis may continue overnight at 4°C to yield a more complete dialysis. Because each sample is different, the optimum time must be derived empirically.
How much sample will I lose in the Slide-A-Lyzer Cassette?
The Slide-A-Lyzer Cassette membrane is made of the same regenerated cellulose that is used in dialysis tubing, so a researcher should expect about the same protein loss one would experience with tubing. As a guide, a 1 mg/ml solution will generally have a recovery rate of greater than 95%. At 100µg/ml, the recovery rate drops to 75%-80%. With a dilute (e.g., 10 µg/ml) protein solution, one can lose up to 50% or more of the sample.
If the Slide-A-Lyzer Dialysis Cassette is not reusable, why are there four portholes?
Researchers can use the two extra portholes to add reagents to the Slide-A-Lyzer Dialysis Cassette at different times. For example, the cassette can be used for both the reaction vessel and dialysis. Reactants can be added directly to the cassette and following the reaction, the cassette can be placed in buffer for dialysis. This may reduce sample loss that often occurs with excessive sample handling. A sample protocol for the biotinylation and dialysis of a protein is shown here.
Is it necessary to buy needles and syringes from Pierce if there are already some available in the lab?
No, any 18-gauge needle that is at least one-inch long and any syringe that is of sufficient volume will work.
Is it necessary to extensively wash or boil the Slide-A-Lyzer Cassette before use to remove contaminants?
No. The Slide-A-Lyzer Cassette membrane requires no pretreatment. Trace metals are present in all Slide-A-Lyzer Cassette membranes. The 7,000 MWCO membranes contain 13% glycerol, 10,000 MWCO membranes contain 12% glycerol and 10,000 MWCO membranes contain 21% glycerol. These items will be lost during the dialysis process. To remove these items before introducing the sample, dialyze against water or a buffer for 10-15 minutes.
Is the Slide-A-Lyzer Dialysis Cassette compatible with organic solvents?
Pierce researchers have successfully used 10% solutions of DMF, DMSO, acetonitrile, methanol, hexane and heptane; 100% acetic acid; and 70% ethanol with the Slide-A-Lyzer Cassette. The units are compatible with sample containing up to 75% acetonitrile and 1% TFA; however, Pierce recommends not dialyzing into a buffer that contains an acetonitrile concentration greater than 10%.
The casing is made of ABS plastic and the gasket is made from a non-leaching silicone-like material. The membrane is made from regenerated cellulose.
What is the highest temperature and the pH range that is compatible with the Slide-A-Lyzer Cassette?
Slide-A-Lyzer Cassettes can be held at 56°C for two hours. At temperatures and times above these, the plastic gets soft and can deform. Pierce recommends that users maintain a pH range of 5-9.
What is the purpose of the buoy?
The buoy suspends the Slide-A-Lyzer Cassette above the stirring bar during dialysis and it provides a benchtop stand on which to set the Slide-A-Lyzer Cassette.
What prevents the Slide-A-Lyzer Dialysis Cassette from leaking?
An internal gasket, which isn't visible after the cassette is assembled, reseals itself as the needle is withdrawn. To maintain sample volume and integrity, users should remember these three key rules:
- Before use, fill the cassette with air to verify that the system is airtight.
- Puncture each porthole only once.
- Do not allow the membrane to come into contact with the sharp needle bevel.
What sizes are available? What MWCO membranes are available?
Four sizes to accommodate samples between 0.1 and 30 ml are currently available in five different MWCOs (2K, 3.5K, 7K, 10K and 20K).
These units, especially those that accommodate smaller volumes, provide for greater sample recovery and shorter dialysis times than one can achieve with traditional tubing.
We have a cassette selection guide to help you choose the appropriate cassette for your application. There are also product demonstrations for this and other High-Performance Dialysis Products.