Field of the invention

The present invention relates to a product and method for cell preservation, such as cell banking of any type of cells for subsequent scientific or medical use. More closely, the invention relates to a product and a method for cryopreservation of cells using vacuum tubes provided with freeze media/cryopreservation liquid.

Background of the invention Today several cell banks exist which store cells, for example human placental or umbilical cord stem cells, for future medical use. There are also cell banks which store cells, cultivated in for example bioreactors, for scientific purposes. Common for all cell banks is that the cells are stored by cryopreservation usually in liquid nitrogen at -196°C.

Cryopreservation is a very manual and time consuming task usually performed under laminar air flow (LAF). Furthermore, it includes several steps with open handling which increases the risk of contamination. Due to the number of steps during traditional cell banking, batch to batch variations might also occur. During cryopreservation of cells, time and temperature are critical factors to eliminate stress such as asphyxiation.

Containers under vacuum, such as the Vacutainer™ , are well-established products used at hospitals and care centers for rapid blood sampling. The containers comprise a vacuum tube that aseptically draws blood through a sleeved covered needle. The vacuum tube is available in various volumes and often pre-coated with various compounds to prevent for example blood clotting. The vacuum tube is inserted into the access device and when the sleeve protected needle penetrates the silicon cap on the vacuum tube the blood automatically will be withdrawn from the patient.

It would be desirable to have a product with which cell banking could be performed without bringing the cells out of the bioreactor and which significantly would shorten the time from bioreactor to the fridge. This would provide a powerful tool to establish large cell banks with very little effort. Summary of the invention

The present invention provides a product and a method for rapid cell banking which reduces possible contamination and handling times and efforts compared to prior art.

Thus in a first aspect the invention relates to a product for cryopreservation of cells, comprising a vacuum tube provided with freeze media, and a penetratable and preferably removable cap on said tube.

Preferably the freeze media is DMSO, glycerol or methtyl cellulose and the vacuum tube is filled with 5-20% v/v , preferably 10% v/v freeze media.

In one embodiment an access device is provided for receiving said vacuum tube. The access device is provided with a hollow needle to be inserted into the vacuum tube and also provided with a connector for connection to a cell source, such as a cell culture in a bioreactor.

In a second aspect, the invention relates to a method for cryopreservation of cells, comprising sampling or harvesting cells into a vacuum tube provided with freeze media; closing said tube with a penetratable cap; and freezing said tube. In a preferred method for cryopreservation of cells, the method comprises cultivating cells in a bioreactor; harvesting or sampling cells from said bioreactor into a vacuum tube provided with freeze media, wherein the cells are instantly mixed with the freeze media; removing said tube from said bioreactor; and freezing said tube and its content.

Preferably the freeze media is DMSO, glycerol or methtyl cellulose and the vacuum tube is filled with 5-20% v/v , preferably 10% v/v freeze media.

In a preferred embodiment, the cells are cultivated as a perfusion culture. Preferably the cells are cultivated to 10-200 MVC/mL.

If desired the cells are incubated before freezing.

One or more steps of the method may be automated.

The method of the invention would nearly eliminate the time from cell harvesting to

cryopreservation, since it will be done in one step. Preferably, the cryopreservation tubes are stored cold before the procedure starts. Brief description of the drawings

Fig 1A shows a schematic view of a vacuum tube prepared with concentrated cryopreservation liquid.

Fig IB shows a schematic view of an access device for receiving the vacuum tube and having a needle for penetrating the lid of the vacuum tube.

Fig 1C shows a schematic view of the access device connected to the vacuum tube and ready to be inserted to the bioreactor for cell sampling.

Detailed description of the invention The present invention will now be described in relation to a non-limiting example and the accompanying figure.

Fig 1A shows a schematic view of a vacuum tube (1) prepared with concentrated cryopreservation liquid (2). The tube is also provided with a penetratable and removable cap (3) and penetratable septum (4) of silicon or other soft material. The tube may be any vessel appropriate for cryo preservation applied with vacuum, for example tubes may be of glass or plastic.

Fig IB shows a schematic view of an access device (5) comprising a protective housing (5) for receiving the vacuum tube and having a needle (6) for penetrating the lid of the vacuum tube. The needle is provided with a protective sleeve (7) of rubber or silicon. The access device is provided with a Luer or other connection to a bioreactor for cell sampling directly into the vacuum tube.

Fig 1C shows a schematic view of the access device (5) connected to the vacuum tube (1) and ready to be inserted to the bioreactor via the connection (8) for cell sampling. The cryo vessel is pushed into the protective cap (3) along the direction of the arrows. The needle will penetrate the soft material septum. The vacuum will withdraw the cell broth from the bioreactor for mixing directly with the cryopreservation liquid (freeze media). Thereafter, the tube is placed in a fridge for cell banking.

Example

Conventional 5 ml vacuum tubes are filled with 0.5 ml concentrated DMSO (freeze media) using a syringe. A CHO (Chinese Hamster Ovary) culture is brought to up to 10-100 MVC/mL, preferably using perfusion culture. The access device with sleeve protected needle (6) is attached to the bioreactor via the connector (8). Cryo- liquid prepared vacuum tubes according to the invention are used to draw cell samples from the bioreactor. The vacuum tubes are inserted in the access device and the vacuum draws the cells broth into the tube through the needle of the access device. The cell broth and the freeze media are instantly mixed.

Thereafter the filled cryo prepared vacuum tubes are directly transferred to a cell banking fridge. If necessary the cells in the tubes are shortly incubated before freezing.

The procedure to draw cell samples from bioreactors does not damage the cells and is very fast which enables production of large cell banks with minimum of open handling. If desired, the process may be automated.