Cryomacs Freezing Bags – A Critical Component in the Successful Delivery of Biological Samples and Therapies

Owing to the ability to preserve a wide variety of elements for such a long period of time, including cells, tissues, blood and DNA, cryopreservation has emerged as a key focus area for stakeholders in the biopharmaceutical industry. It is worth mentioning that it is extremely difficult to store biological components, such as stem cells and tissues, via simple cooling or freezing for an extended period of time due to the formation of ice crystals. Even though, appropriately preserved biologics have immense potential for use in basic research and other medical applications, damage sustained by the membrane during freezing and thawing results in osmotic shock, which can ultimately lead to cell death. The aforementioned challenges have prompted researchers to explore the potential of cryomacs bags that facilitate durable storage of analytes or biological materials at cryogenic temperatures (less than -65°C).

General Overview of the Cryopreservation Process

Cryopreservation is a technique that aids in maintaining biological materials at cryogenic temperatures for an extended period of time, while preserving the original cell structures. It is worth mentioning that the biopreservation process aims to establish biorepositories with relevant biomaterials (such as cells, tissues, blood and body fluids, including plasma or serum) which are maintained in a stable format. While some biobanks (especially non-clinical ones) use mechanical freezers for storage, liquid nitrogen is one of the most reliable cryostorage mediums. The temperature of samples kept in liquid nitrogen storage is known to be exactly -196°C and they are not prone to thermocycling, a risk that is always present in mechanical freezers or vapor nitrogen storage. Due to the infrastructure available for processing, freezing and storing of these container systems, blood bags are the preferred container for cell therapy biopreservation.

The above figure presents a general overview of the cryopreservation process.

Additionally, with the rising popularity of cellular-based technologies and widespread use of cryopreservation techniques in biochemistry, molecular biology (food sciences, ecology, plant physiology, reproductive medicine) and other medical applications, it is becoming crucial to create better preservation techniques that can easily restore normal physiological functions.

Types of Analytes Stored in Cryomacs Bags

A variety of biologics can be stored in cryomacs bags and has been classified into four categories:

1. Blood: According to the American Red Cross, in the US, around 6.8 million people donate blood annually and on a daily basis, approximately 29,000 units of red blood cells are required. Therefore, in order to store and preserve such enormous amounts of blood, single-use assemblies are a necessity. Additionally, successful and long-term preservation of biological specimens have been more effective at cryogenic temperatures (-196°C).

• Biologics: Gene therapy and cell therapy-based futuristic treatments fall under the category of advanced therapy medicinal products (ATMPs) and offer opportunities to individuals suffering from a variety of illnesses, including various types of cancers. Since gene-modified cell therapies rely on genetic alterations made outside of the body of a patient, the corresponding cells must be maintained in a stable state in an ex-vivo setting, for a predetermined amount of time. If the cell structure is to remain intact, long-term storage of cell products needs cryopreservation at temperatures lower than -130°C.

• Cell Cultures: The optimal preservation of stem cells is crucial for maintaining cell viability as they form an essential part of novel therapies and are thus extremely valuable. As a result, precautions must be taken to ensure cell survival prior to when they are further processed and potentially transmitted to a patient. Initially, the sample is stored at -4°C, and then it is frozen down to -156°C (when stored in the vapor phase) or -196°C (when stored in liquid phase).

• Tissues and Organs: Autopsies and surgical procedures are usually performed to collate human tissues and organs. Various factors, such as length of the surgery may have an impact on the degree of tissue degeneration and damage before collection. Usually, to completely freeze tissue samples, a cryovial of the sample is stored in liquid nitrogen or freezers at -80°C.

Challenges Associated with Cryomacs Bags

In this section, the details related to the challenges associated with cryomacs bags have been provided below:

• At the temperatures where cell suspensions are normally held, thermal transition of ethylene vinyl acetate (EVA) makes cryomacs bags that are made of EVA extremely brittle. As a result, during cryopreservation processing and storage, cryomacs bags become fragile and prone to cracking.
• Cell-freezing bag failure during the prolonged storage of cellular product is likely to result in contamination of contents, which could then spread to other items kept in the same liquid nitrogen tank.
• Extensive use of polyvinyl chloride (PVC) tubing to fill bags with samples can turn brittle at conventional storage conditions for biological constructs.
• Plasticizers used to make PVC products flexible leach into the surrounding environment.

Cryomacs Freezing Bags: Future Perspectives

The ability to cryopreserve tissue-engineered products while preserving structure and function is required for large-scale clinical applications. Since engineered tissue alternatives are going through clinical trials, and with upsurge in demand for cultured cells and tissues on the horizon, the tissue engineering community is growing more concerned about supplying adequate quantities of these products to the market. Despite substantial progress in cryopreservation, research on how to optimize cryogenic freezing protocols is still underway. In fact, there is no single optimal temperature for cryopreservation as each type of sample requires specific storage conditions. Considering the current market trends and innovation landscape, we believe that, with a surge in morbidity, indubitably increasing demand for cell cultures with minimized loss of viability, rise in R&D activity and growing popularity of cryomacs bags over traditional storage containers, the cryomacs bags industry is expected to witness steady growth in the coming years.