Structures, Properties and Applications of Alginates

Abstract

Alginate is a hydrocolloid from algae, specifically brown algae, which is a group that includes many of the seaweeds, like kelps and an extracellular polymer of some bacteria. Sodium alginate is one of the best-known members of the hydrogel group. The hydrogel is a water-swollen and cross-linked polymeric network produced by the simple reaction of one or more monomers. It has a linear (unbranched) structure based on d-mannuronic and l-guluronic acids. The placement of these monomers depending on the source of its production is alternating, sequential and random. The same arrangement of monomers can affect the physical and chemical properties of this polysaccharide. This polyuronide has a wide range of applications in various industries including the food industry, medicine, tissue engineering, wastewater treatment, the pharmaceutical industry and fuel. It is generally recognized as safe when used in accordance with good manufacturing or feeding practice. This review discusses its application in addition to its structural, physical, and chemical properties.

Mechanistic Insights into the Selective Synthesis of 4H-Pyran Derivatives On-Water Using Naturally Occurring Alginate from Sargassum muticum: Experimental and DFT Study

“…The structural analysis of the sodium alginate (SA) shows that is formed by a linear copolymer of two homopolymeric blocks of (1→4)-linked α-L-guluronic acid (G) and β-D-mannuronic acid (M) monomers and heteropolymorphic fractions GM, see Scheme 1 [ 30 , 31 ]. All these monomers contain a carboxylate and two hydroxyl groups which can act as a bifunctional heterogeneous organocatalyst for the electrophilic and nucleophilic reactions assisted by carboxylate groups and/or hydrogen bonding [ 32 , 33 , 34 , 35 ].…”

Recent Reports on Polysaccharide-Based Materials for Drug Delivery

“…However, crosslinking between alginate and calcium ions occurs with the participation of GG blocks, while MM and MG are responsible for increasing gel flexibility. Therefore, alginate gel formation strictly depends on the percentage of G and M blocks [ 11 , 12 ]. The alginate-based materials can be used in different medical applications, such as wound healing, tissue engineering, or drug delivery in the form of hydrogels, nano-, microparticles, liposomes, or tablets [ 13 , 14 ].…”

Sodium Alginate-Quaternary Polymethacrylate Composites: Characterization of Dispersions and Calcium Ion Cross-Linked Gel Beads

“…Sodium alginate (SA), a sodium salt of alginic acid, is a natural polysaccharide from marine brown algae. SA has been employed as an additive in foods and pharmaceutical dosage forms [ 1 , 2 ]. SA consists of two uronic acids, namely α-L-guluronic and β-D-mannuronic acids.…”

“…SA consists of two uronic acids, namely α-L-guluronic and β-D-mannuronic acids. The arrangement of both uronic acids is homopolymeric blocks and blocks with an alternating sequence [ 2 ]. SA possesses good hydration and swelling when exposed to water.…”