Methods of extraction, physicochemical properties of alginates and their applications in biomedical field – a review

Abstract

In this paper, the current state-of-art of extraction of alginates and the determination of their physico-chemical properties as well as their overall applications focussing on biomedical purposes has been presented. The quality and quantity of the alginate obtained with a variable yield prepared from brown seaweeds as a result of many factors, such as type of algae, extraction methods, chemical modification and others. Alginates are mainly extracted by using conventional alkaline extraction. However, novel extraction techniques such as microwave and ultrasound assisted extractions have gained a lot of interest. The extraction parameters (e.g., temperature and time of extraction) have critical impact on the alginate physiochemical and mechanical properties and thus, their potential applications. By controlling a chemical process makes it possible get various forms of alginates, such as fibres, films, hydrogels or foams. It is important to characterise the obtained alginates in order to their proper applications. This article presents several techniques used for the analysis of alginate properties. These natural polysaccharides are widely used in the commercial production, as a food ingredient, in the pharmaceutical industry due to their antibacterial, anticancer and probiotic properties. Their gelling characteristic and absorbable properties enable using alginates as a wound management material. Moreover, they are also biocompatible, non-toxic and biodegradable, therefore adequate in other biomedical applications.

Progress in Modern Marine Biomaterials Research

“…Alginates are produced industrially from marine seaweeds, which belong to brown algae [90]. Conventional extraction of alginates consists of the following five steps: (i) acidification of seaweeds; (ii) alkaline extraction using Na 2 CO 3 ; (iii) solid/liquid separation; (iv) precipitation and (v) drying [100]. In addition, seaweed tissue can be softened and bleached using formaldehyde/formalin [100].…”

“…Conventional extraction of alginates consists of the following five steps: (i) acidification of seaweeds; (ii) alkaline extraction using Na 2 CO 3 ; (iii) solid/liquid separation; (iv) precipitation and (v) drying [100]. In addition, seaweed tissue can be softened and bleached using formaldehyde/formalin [100]. About 25% of alginate yield can be achieved in 2 h; however, the extraction can be conducted much faster (in 15-30 min) using ultrasound treatment [101].…”

“…In algae, being constituents of cell wall and inter-cellular matrix, alginates provide mechanical strength and flexibility necessary for the survival in water [100]. Due to their non-toxicity, biocompatibility, biodegradability, non-immunogenicity, and hydrophilicity alginates have a great potential for pharmaceutical and biomedical applications [99].…”

Marine-Derived Polymers in Ionic Liquids: Architectures Development and Biomedical Applications

“…The abundance of marine microalgae and the skeletons of crustaceans is large, but its poor solubility in conventional solvents restricts the efficient extraction of its value compounds. Nevertheless, there are some reports on ILs as extraction mediums for polysaccharides from marine residues [5,7,22,32,33]. Details about the structures, properties, and strategies involving the use of ILs on the dissolution and processing of selected marine polymers are made in the following sections.…”

How alginate properties influence in situ internal gelation in Crosslinked Alginate Microcapsules (CLAMs) formed by spray drying

“…The commercial alginates tested in these studies were all isolated from the cell walls of marine macroalgae, but are marketed for various end-uses (Table 1). The algae source can influence the composition of alginates such as the ratio of guluronates to mannuronates (G/M ratio) (McHugh, 2003;Smidsrod and Skjakbraek, 1990); purification processing conditions can influence polymer size and size distributions (Beata Łabowska et al, 2019;Gomez et al, 2009).…”