Preparation and characterization of tragacanth gum –Alginate microcapsules

Using stem cells in regenerative medicine and tissue engineering is a promising strategy for repairing damaged tissues. However, conventional stem cell delivery methods often face challenges such as low cell viability, poor cell retention, and lack of control over cell differentiation. In this study, we report the preparation of alginate-de-esterified tragacanth (Alg-DET) microcapsules as a potential cell encapsulation vehicle for tissue engineering. Alginate(Alg) is a natural polysaccharide that can form hydrogel microcapsules by crosslinking with calcium ions. De-esterified tragacanth (DET) is a water-soluble analog of tragacanth gum, a plant-derived polysaccharide that contains fucose and xylose residues that can promote cell adhesion and growth. We investigated the effect of process parameters such as alginate concentration, DET/Alg ratio, polymer flow rate, and gas pressure on microcapsules size, shape, and distribution using a co-flow extrusion method. The results showed that increasing the alginate concentration from 1% to 2% w/v increased the microcapsules diameter from 340 µm to 512 µm and decreased their spherical factor (SF) from 0.035 to 0.081, making them more elongated. Increasing the DET/Alg ratio from 0 to 1 also increased the microcapsules diameter from 291 µm to 490 µm and decreased their SF from 0.06 to 0.032. Changing the polymer flow rate from 5 to 15 ml/h slightly changed the microcapsules diameter from 419 µm to 505 µm. Increasing the gas pressure from 0.6 bar to 0.7 bar decreased the microcapsules diameter from 496 µm to 455 µm and increased their size distribution. The size, shape, and distribution of the microcapsules indicate their potential as vehicles for cell encapsulation in cell therapy and tissue engineering.