Biomedical Engineering Reference
In-Depth Information
3.3 Purity
Purity is typically required for drugs. For advanced cell therapy medicinal products it
means elimination or decrease of undesired cells. The unique type of cells in cartilage is
chondrocyte. However cartilage biopsy should carry possible contaminants arising from
fragments of the synovial membrane or from bone. These contaminants could be maintained
during culture and thus become a part of the final products. To minimize these risks we
standardized biopsy collection (data not shown) and developed a chondrocyte-specific
culture method. Nevertheless, to be fully compliant with GMPs, we had to give evidence
that our final products were free of cell contaminants. Therefore we analyzed the engineered
tissues for the presence of two markers, one typical of fibroblasts (collagen type I) and one of
bone phenotype (osteocalcin).
Fig. 6. Proteoglycans immuno-staining on engineered constructs (40X). The image from one
representative sample shows that proteoglycans were homogenously distributed
throughout the whole extra-cellular matrix. Staining was developed using fast red substrate
(red is positive stain).
3.3.1 Materials and methods
The same procedure described for potency validation was utilized (see Section 3.2.1). The
following primary antibodies were used: mouse monoclonal anti-human collagen type I
