Efficient Production of Platelets from Umbilical Cord Blood Stem Cells Using A Collagen-Tragacanth Scaffold in A Multi-Chamber Bioreactor

Background: To date, platelet (PLT) transfusion is the main medical option for the treatment of thrombocytopenia. Nowadays, allogenic PLTs are commonly used for blood donation. Due to the limitations in the preparation and storage of PLTs, researchers try to develop alternative modalities such as bioreactors for the in-vitro expansion and production of PLTs for therapeutic purposes by promoting the differentiation of different types of stem cells into megakaryocytes (MK) and PLTs. Materials and Methods: In this experimental study, umbilical cord blood stem cells (UCB-SC) were differentiated into MK. To this end, a new bioreactor system consisting of six compartments and a two-layer scaffold made of collagen and natural tragacanth gum was developed to mimic a bone marrow-like structure. After MKs were loaded to the top layer of the scaffold, the production rate of PLTs was analyzed under shear stress. Results: Based on the estimation, each MK produced about 17.42 PLTs loaded into the scaffold collagen. This value emerged to be 23.46 and 9.44 PLTs in the collagen-tragacanth and the pure tragacanth scaffold groups, respectively, the increase of PLTs in the collagen-tragacanth scaffold was statistically significant (p < 0.001).The generated PLTs had a positive response in aggregometry as well as interaction with normal PLTs. Conclusion: Taken together, the designed bioreactor with a collagen-tragacanth substrate can be used for the production of a sufficient number of PLTs for clinical purposes.