Figure 3: Characterization of alginate microparticles.

A) Chemical structure of alginate, calcium ions (Ca²⁺), and crosslinking reaction showing the interaction of positive calcium ions (+2) with the carboxylic acid groups of two alginate chains (upper chain in black and lower chain in light gray) in the crosslinked alginate microparticles forming an egg-box structure. (ChemDraw Professional 15.1 was used for the chemical drawings). B) Representative images of the morphology of alginate particles crosslinked with CaCl₂ 0.1M using different alginate concentration: 10 mg/ml, 25 mg/ml, 50 mg/ml, 75 mg/ml, and 100 mg/ml. Scale Bar: 100μm. C) Effect of alginate concentration (10 – 100 mg/ml) in microparticles size (n=10).