The potential of algae as a source of cellulose and its derivatives for biomedical applications

Cellulose has been intensively investigated for biomedical applications, because of its excellent properties, like biodegradability, biocompatibility, abundant availability of renewable resources and cost-effectiveness. Among all sources of cellulose, marine macroalgae or seaweeds, are acquiring tremendous attention, due to their high availability around the world. Moreover, the atypical proliferation of some exotic macroalgae species represents a serious problem to the ecosystems, since their accumulation threatens native oceanic species and resources worldwide. Several studies already reported the successfully extraction of cellulose and its derivatives from brown, green and red macroalgae. The extracted cellulose properties vary according to the type of algae, their maturity and the used extraction methods. This review will cover the main methods used to extract cellulose from algae, focusing on more sustainable ones, as well as its further processing into the various cellulose derivatives. Electrospun nanofibers have revealed great potential for biomedical applications, such as delivery of therapeutic agents, tissue engineering, wound dressings and enzyme immobilization. Pure cellulose presents some drawbacks, such as limited solubility in organic solvents and its inability to fuse due to inter and intra-molecular hydrogen bonding. To overcome these limitations, cellulose derivatives, which includes microcrystalline cellulose, cellulose nanocrystals, cellulose nanofibers, cellulose acetate and carboxymethyl cellulose, have been extensively studied to generate electrospun fibers. Therefore, this review aims to explore the marine seaweeds as a promising source of cellulose and its derivatives, the extraction methodologies of these compounds, as well as to demonstrate the potential of nanofibers developed by electrospinning with algae-based cellulose for biomedical applications.