Designing Lignin-Based Biomaterials as Carriers of Bioactive Molecules

Abstract

There is a need to develop circular and sustainable economies by utilizing sustainable, green, and renewable resources in high-tech industrial fields especially in the pharmaceutical industry. In the last decade, many derivatives of food and agricultural waste have gained considerable attention due to their abundance, renewability, biocompatibility, environmental amiability, and remarkable biological features. Particularly, lignin, which has been used as a low-grade burning fuel in the past, recently attracted a lot of attention for biomedical applications because of its antioxidant, anti-UV, and antimicrobial properties. Moreover, lignin has abundant phenolic, aliphatic hydroxyl groups, and other chemically reactive sites, making it a desirable biomaterial for drug delivery applications. In this review, we provide an overview of designing different forms of lignin-based biomaterials, including hydrogels, cryogels, electrospun scaffolds, and three-dimensional (3D) printed structures and how they have been used for bioactive compound delivery. We highlight various design criteria and parameters that influence the properties of each type of lignin-based biomaterial and corelate them to various drug delivery applications. In addition, we provide a critical analysis, including the advantages and challenges encountered by each biomaterial fabrication strategy. Finally, we highlight the prospects and future directions associated with the application of lignin-based biomaterials in the pharmaceutical field. We expect that this review will cover the most recent and important developments in this field and serve as a steppingstone for the next generation of pharmaceutical research.

Lignins as Promising Renewable Biopolymers and Bioactive Compounds for High-Performance Materials

“…A drastic increase in the number of published articles, 336 (1990-2022) in the field of lignin hydrogels, suggests the importance of this research area [38,210] or future development, with 55 publications on lignin in drug delivery in 2022 and with most of them being focused on LNPs [211]. A major prerequisite for lignin with respect to synthesizing hydrogels is the abundance of phenolic OH groups in the lignin backbone which can crosslink with COOH groups of the co-joining monomer.…”

Lignin Extracted from Various Parts of Castor (Ricinus communis L.) Plant: Structural Characterization and Catalytic Depolymerization

“…Castor plants, as lignocellulosic biomass, are primarily composed of cellulose, hemicellulose and lignin, in which carbohydrates (cellulose and hemicellulose), as cell wall polysaccharides, can be used as sustainable feedstock for the production of low-cost chemicals, biofuels, and materials [ 7 , 8 , 9 , 10 , 11 , 12 ]. However, the existence of the physical entanglements between the three components, especially the lignin–carbohydrate complex linkages, impedes the efficient conversion of polysaccharides for valorization [ 13 , 14 , 15 ].…”