Sodium Alginate (SA) is a white to pale yellow powder or granular substance at room temperature, readily soluble in water to form a viscous, transparent colloidal solution. As a natural linear polysaccharide extracted from brown algae, its molecular chain is composed of β-D-mannuronic acid and α-L-guluronic acid units. The core of its chemical properties lies in the carboxyl groups on its molecular chain, which can undergo ionic cross-linking reactions with polyvalent metal ions (particularly calcium ions), forming a thermo-irreversible gel. Leveraging its exceptional gelling, thickening, film-forming, and biocompatible properties, its primary application is as a safe food additive (thickener, stabilizer, gelling agent) used in products such as jelly, ice cream, and yogurt. It is also widely utilized in the pharmaceutical field (e.g., wound dressings, drug delivery carriers), as a hydrogel matrix in bioprinting and tissue engineering, as a printing paste in textile dyeing and printing, and as a material for dental impressions.