Automated Frozen Storage: State-of-the-art And Novelty

By Author: Bonanno Begin
Total Articles: 1
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Advances in technology continue to expand the availability of storage systems for biological specimen collections. Selection of storage equipment should be based on the type of biological samples to be conserved, the length of storage time and on the intended use for the specimen. Cryogenic storage in liquid nitrogen (LN2) is effective long-term storage because the extreme cold slows the majority of processes that cause specimens to deteriorate. Vapor phase storage is preferred over storage in liquid phase of nitrogen because it guarantees sufficiently low temperatures to preserve biological samples, but avoids safety hazards related to liquid phase storage. The correct freezing protocol and perfect storage improve cellular viability after thawing. Alternatively, mechanical freezing at -20, -40, -80 and -140°C is required for proteins, nucleic acids and bacterial glycerol stocks storage, but is not recommend for viable cells.

Automated frozen storage is becoming more prevalent worldwide for several reasons. Firstly, the good laboratory procedures (GLP) usually prefers and accepts automated frozen storage because it limits ...
... manual errors and misleading information about biological specimen conserved, and improves quality assurance. Furthermore, these systems may reduce long-term cost for storage. Thus, automated frozen storage is largely used in repositories and bio-banks, where thousands of samples may be stored. However, automated freezers are successfully employed in universities and research institutes. An example is the PlasmidID, a community-based resource portal created to facilitate the search and retrieval of plasmids. In 2006, the Dana Farber and the Harvard Cancer Center generated a repository of more than 46000 plasmids. Each construct was cloned and stored as a glycerol stock at - 80°C in an automated freezer. Retrieval is completely automated and integrated with the PlasmidID portal. This automated system allows overcoming some problems due to equipment failure, poor record keeping, personnel turnover and organizational changes that can lead to loss of clone samples and/or supporting information over time. Furthermore, the integrated software alerts indicate when a sample has experienced more than 6 freeze-thaw cycles or if the storage is longer than four years, supporting the scientist staff to guarantee the viability of clones.

Automated frozen storage may also be used in hospitals where biological samples from patients may be managed and stored in high quality standard. In this case, in addition to technical specification about the repository, ethical issues related to patients' privacy should be considered. Biological specimens have to be anonymous in the database and a univocal protocol to correlate patient to his/ her sample should be optimized.

Thus, automated frozen storage is recommended, and in certain cases mandatory for gold standard procedures in companies, research institutes and hospitals.

Until now, the availability of automated frozen storage has been limited to mechanical freezing. RURO, Inc. and ALS (Angelantoni Life Science) SmartFreezer® have joined the need to freeze biological specimen in LN2 with an automated system. It includes a nitrogen tank to freeze samples in vapor phase; the onboard robot provides access to samples and can retrieve requested material without any manual operation. The 2D barcode or RFID tags directly fixed to the vial identify each sample; FreezerPro® software from RURO, Inc. works as a platform to manage the SmartFreezer®.

The main advantage to applying a robotic system to LN2 storage is the possibility to use automated storage for biological specimen that need extremely low temperature to be conserved. Examples of this would be cell lines and primary tissue culture that are usually stored in LN2 vapor phase in order to preserve viability at thaw. The automated system controls the nitrogen temperature level and manages tank re-fill when necessary. The SmartFreezer® is fully compliant with the FDA GMP/ GLP requirements and the possibility of errors is limited because samples are directly identified by robot via two codes. The SmartFreezer® is capable of storing up to 17000 1.4 ml vials or 10000 2 ml vials. A similar amount of samples would require specialized personnel to be manually managed and free access to liquid nitrogen tanks is not recommended to avoid confusion and mistakes. Considering the long term storage costs, including nitrogen implant, tank maintenance, personnel, and biohazard risks of LN2, many institutes have chosen to create common repositories for cell cultures and biological specimens that need low temperature storage. Lack of an automated frozen system may increase the possibility of cross-contamination, plus samples change regularly and poor traceability is quite high. Hospitals often require a GMP/ GLP repository for patients' tissues and other biological specimens, and storage devices may be shared between several departments and divisions. In this case, the need to correctly identify and retrieve samples is associated with the legal restriction to preserve the privacy and anonymity of samples. Thus, the use of an automated frozen storage system should be recommended in research institutes and hospitals in order to increase the quality of research and medical services and reduce long-term costs.

The novelty of SmartFreezer® to apply the robot to liquid nitrogen storage fills an important gap in automated frozen storage technology. Now, biological specimen that cannot be effectively stored in the existing mechanical freezers could be frozen, conserved and retrieved in automated manner. The key benefits of an automated frozen storage system, including efficiency, safety, and compliance to GMP/ GLP requirements, are also successfully feasible for nitrogen storage procedures.

For more information about Automated frozen storage, please visit http://www.ruro.com/.