April 13, 2024
Cell Processing

Navigating the Complexities of Cell Processing: Strategies and Innovations

Understanding Cell Processing

Cell processing is the collection and preparation of cells from biological tissues for various applications like research, therapy and other industrial uses. As regenerative medicine and cellular therapies advance, cell processing plays a pivotal role in isolating and culturing cells from different sources.

Sourcing Cells
Cells can be sourced from various tissues in the human body depending on their intended use. Some of the commonly used cell sources include:

Bone Marrow – Bone marrow is a rich source of mesenchymal stem cells (MSCs), hematopoietic stem cells and other immune cells. Bone marrow sourcing involves aspirating the liquid portion of marrow from hip bones or other large bones under anesthesia.

Adipose Tissue – Adipose or fat tissue contains adipose-derived stem cells (ADSCs) that have shown therapeutic potential. Liposuction is commonly used to source fat cells from various parts of the body in a minimally invasive manner.

Skin – Fibroblasts, keratinocytes and melanocytes can be isolated from skin biopsies or discarded skin tissue after surgical procedures. They find use in wound healing and skin regenerative therapies.

Umbilical Cord – The umbilical cord, umbilical cord blood and amniotic membrane are excellent sources of MSCs, hematopoietic stem cells and other cell types. They are usually collected non-invasively after normal full-term births.

Other sources being explored include placenta, amniotic fluid, dental pulp, liver, pancreas and corneal limbus among others. The choice of tissue depends on the cell types required and their availability with appropriate donor consent.

Isolation and Culture Expansion
Once the source tissue is collected, cells must be isolated away from other components using enzymatic and mechanical methods. For example, bone marrow aspirate is treated with collagenase or hyaluronidase to break down connective tissues and release MSCs.

Isolated cells are cultured in special growth media supplemented with serum, growth factors and antibiotics to support their growth and expansion while preventing bacterial/fungal contamination. Culture conditions are optimized for individual cell types to achieve maximum proliferation.

Cell Processing are passaged when they reach 80-90% confluence by dissociating and re-plating them in fresh media. Typically, 10-15 population doublings can be achieved through several passages over 2-4 weeks to obtain billions of cells from the original sample. Proper culture environment including temperature, humidity, CO2 levels etc. are carefully maintained during expansion.

Cell Separation and Purification
For certain applications, a homogeneous cell population may be required. This necessitates further separation or purification of the expanded cell mix obtained from isolation and culture. Commonly used separation techniques include:

Flow Cytometry – Cells are passed through a flow cytometer where they get tagged with fluorescent cell markers and separated based on their marker expression profiles using deflection and charges. This allows isolation of cell sub-populations.

Magnetic-Activated Cell Sorting (MACS) – Cells are magnetically labelled with antibodies against antigens specific to the desired cell type. When passed through a MACS column in a magnetic field, positively labeled cells get separated.

Density Gradient Centrifugation – Cells at different densities resolvable when centrifuged on density gradients of solutions like Ficoll-Paque or Iodixanol. Mononuclear cells separate from other components and erythrocytes.

These techniques aid in obtaining highly purified cell populations suitable for precise downstream applications with high viability and functionality. Purity levels above 95% can regularly be achieved through combinations of techniques.

Quality Checks and Documentation
No cell processing workflow is complete without rigorous quality checks. Critical parameters that are evaluated include:

Cell Counts – Viability, yield, purity and phenotype confirmation through microscopy and flow cytometry

Sterility Testing – Bacterial, fungal and endotoxin screening of final cell dose

Characterization – Assessment of cell surface markers, differentiation potential, viability across freeze-thaw cycles

Genetic Stability – Karyotyping to rule out detrimental genomic changes

Mycoplasma Detection – Universal PCR testing for contaminating mycoplasma species

Comprehensive documentation is maintained to ensure compliance with current Good Manufacturing Practices. Systems like LIMS also enable full traceability of the processed cells back to the source material. Together, these quality practices guarantee safety and reliability of processed cells.

Final Applications
Depending on their therapeutic potential, processed and characterized cells can be utilized in the following applications:

– Regenerative Medicine – Transplantation of MSCs, endothelial cells or other specialized cell types for tissue/organ repair.

– Cellular Therapies – Usage of hematopoietic stem cells, immune cells, pancreatic islets etc. for conditions like cancer, diabetes.

– Toxicity Testing – Cells are exposed to novel compounds/drugs to study cytotoxicity, safety pharmacology.

– Disease Modeling – Generating in vitro experimental systems mimicking human diseases through cell reprogramming, organoids etc.

– Bioprocessing – Mass production of therapeutic proteins, antibodies or viral vectors in immortalized mammalian/stem cell bioreactors.

– Cosmetics – Formulating anti-aging creams incorporating youth factors secreted by dermal fibroblasts.

Careful translation of new cell-based strategies from lab to clinic relies heavily on standardized, scalable and well-documented cell processing methodologies. Continued technological innovations coupled with rigorous oversight will help realize the vast therapeutic potential of various cell types in years to come.

*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it