Apparatus and methods relating to freezing at least part of a biological sample
Disclosed is a device for use in freezing at least part of a biological sample in a receptacle, e.g. a vial or a cryopreservation bag, the device comprising: a base; and a receptacle holder comprising: a first part configured to, with the receptacle held by the receptacle holder during cooling of the base using a cooler device, withdraw heat energy from a first portion of the receptacle at a first heat withdrawal rate; and a second part configured such that, with the receptacle held by the receptacle holder during cooling of the base using the cooler device, a second heat withdrawal rate of heat energy withdrawal from a second portion of the receptacle via the second part is less than the first heat withdrawal rate. A temperature gradient may be established in the sample to enable progressive solidification to occur in the sample. A receptable for use in freezing a biological sample, and a freezing method are disclosed also.
1. A device for use in freezing at least part of a biological sample in a receptacle, the device comprising:
a base;
a plurality of walls extending from the base, wherein each wall of the plurality of walls comprises at least one cutout configured to partially receive the receptacle therein, such that the receptacle is not fully enclosed; and
a receptacle holder comprising:
a first part in contact with a first portion of the receptacle configured to, with the receptacle held by the receptacle holder during cooling of the base using a cooler device, withdraw heat energy from the first portion of the receptacle at a first heat withdrawal rate; and
a second part in contact with a second portion of the receptacle configured such that, with the receptacle held by the receptacle holder during cooling of the base using the cooler device, a second heat withdrawal rate of heat energy withdrawal from the second portion of the receptacle via the second part is less than the first heat withdrawal rate;
wherein the first part and the second part simultaneously cool the first portion of the receptacle and the second portion of the receptacle at the first heat withdrawal rate and the second heat withdrawal rate, respectively.
2. The device according to claim 1 , wherein the first part is configured to at least partially surround the first portion and the second part is configured to at least partially surround the second portion.
3. The device according to claim 1 , wherein the first part is closer to the base than the second part.
4. The device according to claim 1 , wherein the second part is configured to withdraw heat energy from the second portion of the receptacle at the second heat withdrawal rate.
5. The device according to claim 1 , wherein a difference between the first heat withdrawal rate and the second heat withdrawal rate is at least sufficient to establish a temperature gradient within a sample in the receptacle such that, during a freezing operation using the cooler device, ice nucleation occurs in a first region of the sample, the first region in contact with the first portion of the receptacle, without ice nucleation in a second region of the sample, the second region in contact with the second portion of the receptacle.
6. The device according to claim 1 , wherein a difference between the first heat withdrawal rate and the second heat withdrawal rate is such that, for a sample having a volume of 5 millilitres in the receptacle, a temperature difference between a first region of the sample in contact with the first portion of the receptacle and a second region of the sample in contact with the second portion of the receptacle during cooling of the base is at least 15 degrees Celsius.
7. The device according to claim 1 , wherein the first part comprises a metal and the second part comprises a polymer.
8. The device according to claim 1 , wherein the first part comprises a first material with a first value of a heat flow characteristic and the second part comprises a material with a second value of the heat flow characteristic, different from the first value.
9. The device according to claim 8 , wherein the heat flow characteristic is a thermal conductivity.
10. The device according to claim 9 , wherein the first value comprises a thermal conductivity of at least 10 W/mK.
11. The device according to claim 9 , wherein the second value comprises a thermal conductivity of at most 1 W/mK.
12. The device according to claim 1 , wherein the base comprise a plate and the first part is part of a surface of the plate.
13. The device according to claim 1 , wherein the base comprises a plate and wherein the first part is a first wall part of each of the plurality of walls and the second part is a second wall part of each of the plurality of walls.
14. The device according to claim 13 , wherein each of the plurality of walls comprises an opening through the wall.
15. The device according to claim 14 , wherein a first width of the opening is narrower than a second width of the opening, the first width closer to the base than the second width.
16. The device according to claim 13 , wherein a base portion of each of the plurality of walls is wider than a non-base portion of each of the plurality of walls, the base portion of the wall being closer to the base than the non-base portion of the wall.
17. The device according to claim 13 , wherein each of the plurality of walls is slidably mounted on the base.
18. The device according to claim 1 , wherein the receptacle holder is configured to hold the receptacle along a freezing operation temperature gradient axis extending away from the base, the first part comprising a first surface and the second part comprising a second surface further from the temperature gradient axis than the first surface.
19. The device according to claim 18 , wherein the receptacle holder is configured such that, with the receptacle held by the receptacle holder, a first volume of ambient gas between the first surface and the first portion of the receptacle is less than a second volume of ambient gas between the second surface and the second portion of the receptacle.
20. The device according to claim 1 , the first part comprising a first surface and the second part comprising a second surface, the receptacle holder comprising a recess to receive the receptacle, the first part comprising a third surface opposed from the first surface across the recess, and the second part comprising a fourth surface opposed from the second surface across the recess, wherein a first width of the recess taken between the first surface and the third surface is less than a second width of the recess taken between the second surface and the fourth surface.
21. The device according to claim 20 , wherein the recess tapers towards the base.
22. The device according to claim 1 , wherein the base is contactable with a cooling surface of the cooler device.
23. A receptacle for use in freezing a biological sample contained therein, the receptacle comprising:
a first portion configured to transfer heat energy from a first inner surface of the first portion to a first outer surface of the first portion at a first heat transfer rate; and
a second portion configured to transfer heat energy from a second inner surface of the second portion to a second outer surface of the second portion at a second heat transfer rate, the second heat transfer rate less than the first heat transfer rate;
wherein the first portion and the second portion simultaneously transfer energy at the first heat transfer rate and the second heat transfer rate, respectively.
24. The receptacle according to claim 23 , wherein the first portion comprises a first material having a first value of a heat flow characteristic and the second portion comprises a second material having a second value of the heat flow characteristic, different from the first value.
25. The receptacle according to claim 24 , wherein the heat flow characteristic is a thermal conductivity.
26. The receptacle according to claim 23 , wherein the receptacle comprises an internal cavity for receiving a biological sample, the first portion comprising a third inner surface opposing the first inner surface across the internal cavity, the second portion comprising a fourth inner surface opposing the second inner surface across the internal cavity, wherein a distance between the first inner surface and the third inner surface is greater than a distance between the second inner surface and the fourth inner surface.
27. The receptacle according to claim 23 , wherein a difference between the first heat transfer rate and the second heat transfer rate is at least sufficient to establish a temperature gradient within a sample in the receptacle such that, during a freezing operation with heat transfer via the first portion and the second portion, ice nucleation occurs in a first region of the sample, the first region in contact with the first portion, without ice nucleation in a second region of the sample, the second region in contact with the second portion.
28. A method of freezing part of a biological sample in a receptacle, the method comprising:
arranging the receptacle in a receptacle holder formed of a base and a plurality of walls extending from the base, wherein each wall of the plurality of walls comprises at least one cutout configured to partially receive the receptacle therein, such that the receptacle is not fully enclosed;
cooling the receptacle holder using a cooler device;
withdrawing, during cooling of the receptacle holder using the cooler device, heat energy from a first portion of the receptacle via a first receptacle holder part of the receptacle holder, in contact with the first portion of the receptacle, at a first heat withdrawal rate; and
causing, during cooling of the receptacle holder using the cooler device, a second heat withdrawal rate of heat energy withdrawal from a second portion of the receptacle via a second receptacle holder part of the receptacle holder, in contact with the second portion of the receptacle, to be less than the first heat withdrawal rate;
wherein the first portion and the second portion are simultaneously cooled at the first heat withdrawal rate and the second heat withdrawal rate, respectively.
29. The method according to claim 28 , comprising withdrawing, during cooling of the receptacle holder using the cooler device, heat energy from the second portion of the sample via the second receptacle holder part at the second heat withdrawal rate.
30. The method according to claim 28 , wherein a difference between the first heat withdrawal rate and the second heat withdrawal rate is at least sufficient to establish a temperature gradient within the biological sample such that, during a freezing operation using the cooler device, ice nucleation occurs in a first region of the biological sample, the first region in contact with the first portion of the receptacle, without ice nucleation in a second region of the biological sample, the second region in contact with the second portion of the receptacle.