Concentration of lentiviral particles via ultracentrifugation

Materials
	Virus containing supernatant
	20% sucrose in PBS
	1% BSA in PBS

Procedure

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1. 4 ml of 20% sucrose solution are added to an ultracentrifuge tube and overlayed with 26 ml of filtrated virus containing supernatant
2. the tubes are placed in aerosol tight swing buckets
3. centrifugation is carried at 20.000 rpm , 4°C for 2h15min (Rotor: SW32Ti)
4. after discarding the supernatant the pellet is resuspended in 250µl 1%BSA
5. Aliquot and freeze in liquid nitrogen
6. Store at -80°C (repeated freezing and thawing might result in titer reduction)