ExpressMag System FAQs


What is the coating on the ExpressMag beads?

The ExpressMag beads are coated with a propriety polymeric shell that enables it to bind to the surface of most viral particles.

Will the ExpressMag system only enhance the transduction of MISSION lentiviral particles?

We have explicitly validated ExpressMag with the MISSION lentiviral particles. We have preliminary data to suggest that ExpressMag will work with many other viral types including other lentiviral particles such as SIV and adenoviral particles.

What happens to the ExpressMag beads after they bind to the surface of the cell?

The beads end up in the lysosome of the cell. After this it is not clear how the cell further processes the beads. While at the recommended dosages of ExpressMag beads we have not observed cytotoxicity, there is the possibility that proteins/genes could be differentially regulated in the presence of these beads. As with any experiment, it is critical to run an ExpressMag beads alone as a negative control.

Can I utilize the ExpressMag system in a tissue culture incubator?

For incubation times longer than 15 minutes or for cells that are particularly sensitive to temperature fluctuation, it may be useful to utilize the ExpressMag system entirely in a tissue culture hood. As with all magnets, increases in temperature decrease the strength of the magnetic field in the ExpressMag Super Magnetic Plate and ExpressMag 96-Well Magnet. While the difference between room temperature and a tissue culture incubator is quite small for the magnets, it will slightly decrease the strength of the magnetic field. This may or may not have an effect on your transduction efficiency. Thus, for cells or protocols that are very sensitive to temperature changes, the possibility of a slight decrease in transduction efficiency will be readily overcome by an increase in the overall performance of your assay.

Why can’t I autoclave my ExpressMag magnets?

Autoclaving could permanently decrease the magnetic properties of the magnets, thus rendering them useless.

Do you have any publications regarding ExpressMag?

We are currently collecting articles regarding use of ExpressMag products. If you have utilized ExpressMag products, in a peer-reviewed paper email with the reference, and we will send you a free Lenti stressball.

What other types of virus have been utilized with the ExpressMag system?

We have data, but no publications, on utilization of adenovirus, retrovirus, lentivirus, and bacalovirus.

What is the overall size of the nanoparticle?

The hydrodynamic radius is around 100 nm.

What is the advantage of the ExpressMag system vs. spinoculation?

Both systems attempt to concentrate the virus at the surface of the cells to increase transduction efficiency. The ExpressMag system is far less expensive and saves you time when compared to traditional "spinoculation." For example, all that is needed is an ExpressMag magnet and beads. For spinoculation, a temperature controlled table top centrifuge with a swinging bucket rotor must be purchased. Finally, an attachment to allow plates to be centrifuged must also be purchased. With the ExpressMag system, there is only a one time purchase of a magnet and the periodic purchase of magnetic beads for your lentiviral transduction experiments.

The ExpressMag system also saves you a significant amount of time when compared to spinoculation. Spinoculation requires a 30 minute centrifugation, a 24 hour incubation, and another 30 minute centrifugation. With the ExpressMag system there is only one 15 minute incubation.

MISSION is a registered trademark of Sigma-Aldrich Co. LLC Label License.
ExpressMag is a trademark of Sigma-Aldrich.

back to top
back to ExpressMag Lentiviral Delivery Reagent