Selective access to cryopreserved samples
Inventors
Childs, Richard W. • Cullis, Herb • Vasu, Sumithira • Broussard, Phillippe Jean • Clark, Kevin Douglas • Harting, Eric Kelsey
Assignees
US Department of Health and Human Services
Publication Number
US-8790597-B2
Publication Date
2014-07-29
Expiration Date
2030-05-04
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Abstract
Methods and apparatus for selectively accessing a portion of a sterile cryopreserved sample are disclosed. The apparatus may include a container configured to receive the cryopreserved sample and having a first portion and a second portion, a heat sink chamber surrounding the first portion of the container, and a heat source adjacent to the second portion of the container. The chamber may be configured to maintain a non-accessed portion of the sample in a cryopreserved state. The heat source may be configured to separating an accessed portion of the sample from the non-accessed portion of the sample while maintaining the viability of the accessed portion while the non-accessed portion is maintained in the cryopreserved state.
Core Innovation
The invention relates to methods and apparatus for selectively accessing a portion of a sterile cryopreserved sample, such as umbilical cord blood (UCB) units, frozen bone marrow, or frozen mobilized hematopoietic progenitor cells, while maintaining the remainder of the sample in a stably frozen state. The apparatus includes a container for the cryopreserved sample with first and second portions, a heat sink chamber surrounding the first portion, and a heat source adjacent to the second portion. This configuration allows separation of an accessed portion of the sample from the non-accessed portion while preserving viability and sterility of both.
The problem addressed arises from clinical needs in hematopoietic stem cell transplantation where patients lack suitable HLA-matched donors and rely on UCB transplants. Although UCB transplantation has benefits such as lower graft-versus-host disease (GVHD) rates, complications including severe GVHD and viral reactivation still cause morbidity and mortality. A major challenge is the inability to selectively thaw and access a small portion of a frozen UCB unit to expand immune cells, such as NK cells or viral-reactive T-cells, prior to transplantation. Existing methods require thawing the entire unit, eliminating the donor cell source for subsequent expansions to prevent complications.
The invention overcomes these limitations by providing methods and apparatus to selectively thaw or sever a portion of a cryopreserved sample in its container while maintaining the non-accessed portion frozen and viable. For example, one embodiment uses a liquid nitrogen-cooled block to maintain the non-accessed portion frozen while heated severing bars melt and seal the container to isolate the accessed portion. Another embodiment uses deformable bladders filled with liquid nitrogen to surround the frozen portion while selectively thawing a defined aliquot with controlled infrared heat. Additional features include use of patch layers and release films to prevent container damage during severing and seal formation. This selective access enables in vitro expansion of immune cells from the accessed portion in advance of UCB transplantation, potentially reducing GVHD and viral infection-related complications.
Claims Coverage
The patent includes independent claims focusing on apparatus and construction for selective access to cryopreserved samples, emphasizing heat sink chambers with notches, heat sources with heating and sealing elements, and patch/release layers to facilitate sealing while maintaining viability and sterility.
Heat sink chamber with notch for selective enclosure
An apparatus including a heat sink chamber having a notch sized to receive a first portion of a sterile cryopreserved sample container, allowing the second portion to remain outside while keeping the first portion stably frozen.
Heat source with tapered severing bars and controlled heating
A heat source comprising two tapered severing bars each with a heating element whose temperature is controlled to sever and seal the container between first and second portions selectively. The severing bars include a pressure source to push against the container to facilitate sealing.
Use of patch layer and release film for sealing integrity
An apparatus incorporating a patch layer with melting point similar to the container material surrounding at least part of the container, coupled with a release film having a higher melting point between the patch layer and heat source. This arrangement welds the patch to the container upon heating and prevents sticking of heating elements, enhancing seal integrity and preventing container damage.
The independent claims cover inventive features relating to selective enclosure of sample portions via a notched heat sink chamber, controlled thermal severing and sealing with tapered, heated severing bars applying pressure, and the use of patch and release layers to ensure container integrity and effective sealing.
Stated Advantages
Ability to selectively access or thaw a portion of a cryopreserved sample without compromising the integrity, sterility, or viability of the unthawed portion.
Opportunity to expand immune cells (NK cells, T-cells, hematopoietic stem cells) ex vivo prior to transplantation, potentially reducing incidence of GVHD and post-transplant viral infections.
Maintains the non-accessed portion of the sample in a stably frozen state during seal formation and partial thaw, preserving cell viability comparable to conventional methods.
Provides sterile removal of sample portions, minimizing contamination risk.
Enables multiple selective accesses or thaws of a single cryopreserved sample at different times.
Documented Applications
Selective access to umbilical cord blood units for obtaining aliquots used in ex vivo expansion of natural killer (NK) cells for adoptive infusion to reduce graft-versus-host disease (GVHD) and enhance graft-versus-tumor effects after transplantation.
Selective access to cryopreserved samples to obtain portions for ex vivo expansion of viral-reactive T lymphocyte cells to reduce viral infection-related mortality in cord blood transplantation recipients.
Use of selective thawing for samples including other biological materials such as frozen bone marrow, mobilized hematopoietic progenitor cells, plasma, serum, lymphocytes, and other cellular or non-cellular samples requiring partial thaw without compromising the remainder.
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