I suggest this article

Hi

I guess it depends on how much vector and how pure you need it. For small scale work we use the Centriprep 15mL 30kDa cut-off kit:

https://www.merckmillipore.com/GB/en/product/Centriprep-Centrifugal-Filter-Unit-with-Ultracel-30-membrane,MM_NF-4307?ReferrerURL=https%3A%2F%2Fwww.google.co.uk%2F&bd=1#overview

Due to the low molecular weight cut-off (I wish they made >1MDa versions), I recommend harvesting vector in serum-free media (i.e. after transfection media change) otherwise you'll never concentrate due to the FBS blocking the filter. The nice thing about these filters is that the liquid flows into the central chamber (and discard). This means that the vector is not being forced directly onto the filter but instead moves towards the bottom of the tube. Most other similar devices effectively force the vector onto the filter, and that's where you tend to get losses; either by not recovering vector at all or recovering vector with sheared-off envelope. Hence, this is also a great device for 'sensitive' envelopes that don't like high speed centrifugation. This device also allows you to buffer-exchange your vector by repeat loading/spinning in your final buffer.

Larger volumes will require double centrifugation (low speed O/N, followed by Ultra). 

Hope that helps!

Dan

Thank you very much Paola and Dan. I appreciate your help :)

Pratap