Synthesis and Characterization of Lignin Hydrogels for Potential Applications as Drug Eluting Antimicrobial Coatings for Medical Materials

Abstract

Lignin is the second most abundant biopolymer on the planet. It is a biocompatible, cheap, environmentally friendly and readily accessible material. It has been reported that these biomacromolecules have antimicrobial activities. Consequently, lignin (LIG) has the potential to be used for biomedical applications. In the present work, a simple method to prepare lignin-based hydrogels is described. The hydrogels were prepared by combining LIG with poly(ethylene glycol) and poly(methyl vinyl ether-co-maleic acid) through an esterification reaction. The synthesis took place in the solid state and can be accelerated significantly (24 vs 1 h) by the use of microwave (MW) radiation. The prepared hydrogels were characterized by evaluation of their swelling capacities and with the use of infrared spectroscopy/solid-state nuclear magnetic resonance. The prepared hydrogels showed LIG contents ranging between 40% and 24% and water uptake capabilities up to 500%. Furthermore, the hydrophobic nature of LIG facilitated loading of a model hydrophobic drug (curcumin). The hydrogels were capable of sustaining the delivery of this compound for up to 4 days. Finally, the materials demonstrated logarithmic reductions in adherence of Staphylococcus aureus and Proteus mirabilis of up to 5.0 relative to the commonly employed medical material poly(vinyl chloride) (PVC).

Spherical lignin particles: a review on their sustainability and applications

“…(ii) reproducibility (iii) easy application and cost-effectiveness (iv) tailored surface morphology and (v) environmental friendliness. 131 Spherical lignin particles seem beneficial regarding many of the above requirements, since lignin can provide surfaces with UV-protection, 132 corrosion inhibition, 133,134 antimicrobial activity, 129,130 removable/self-healable, 135 as well as fire-retardant 136 and drug release properties, 137 making lignin attractive for functional coating purposes.…”

Lignin for Nano‐ and Microscaled Carrier Systems: Applications, Trends, and Challenges

“…Lignin is a fascinating biopolymer with a high valorization potential. Besides being the most abundant aromatic renewable biopolymer, its complex structure is responsible for its antioxidant and antimicrobial activity . Lignins arise from the plants’ secondary metabolism of 4‐hydroxyphenylpropanoid precursors that differ in the number of methoxy groups at the 3‐ and 5‐positions of the phenolic ring .…”

Hydroxymethylation of technical lignins from South American sources with potential use in phenolic resins

“…The preparation of novel materials from lignin/lignin‐derived products can improve theeconomics of polymer composite materials as well as possibly address the problem of its waste disposal . The applications include the production of epoxy, polivinilalcohol, polydimethylsiloxane, polypropylene, polyethylene, controlled drug release, ion removal, hydrogels, bitumen, refiner(carbon cracker), cement additives, biofuel, high‐grade lignin, mixtures of benzene, toluene, and xylene (BTX),activated carbon, phenolic resins, carbon fibers, and vanillin…”