Lignin Nanoparticles: Green Synthesis in a γ-Valerolactone/Water Binary Solvent and Application to Enhance Antimicrobial Activity of Essential Oils

Abstract

Lignin nanoparticles (LNPs), as a special aggregate of renewable and biodegradable lignin available in abundant amounts, are a perfect building-block material because of their advantages, including good dispersibility in water, great biocompatibility, and eco-friendly characteristics. To exploit a promising method of producing LNPs, we developed a simple and sustainable synthesis approach using a recycled γ-valerolactone (GVL)/water binary solvent (GWBS). Up to 200 g/L lignin from several sources could be completely dissolved in GWBS. LNPs were easily obtained through nanoprecipitation (dropping or dialysis) of the lignin solution. The yield and size of LNPs can be controlled during nanoprecipitation. The highest yield of LNP reached 90% via dropping nanoprecipitation, and its relevant initial concentration was up to 24 g/L. This highly efficient dropping method might provide a method for scaled-up production of LNPs. The resultant LNPs, having a diameter of ca. 250 nm and a ζ-potential of −40 mV, also showed good dispersibility and stability in water. LNPs can stabilize essential oils and promote their growth inhibition activity against microbes. These results indicated that we also initiated a new method of achieving enhanced antimicrobials with whole biomass-based chemicals.

Green Synthesis and Characterization of Gold Nanoparticles Using Lignin Nanoparticles

“…With The development of material science, The regular structure of nanomaterials is essential to The design of functional materials for advanced applications. Moreover, The recent progress in The preparation of lignin nanoparticles (LNPs) inspired The design of lignin-based functional materials [16][17][18]. Thus, The green synthesis of well-dispersed Au NPs with LNPs is important for The preparation of composite lignin-derived materials.…”

Preparation and Characterization of Size-Controlled Lignin Nanoparticles with Deep Eutectic Solvents by Nanoprecipitation

“…Though the concentration of lignin used, 3–9 wt %, in our research is much higher than the reported 0.05–2% [ 28 , 29 , 30 ] in the THF system, the obtained LNPs display uniform particle size. This will certainly solve one of the major issues of industrial lignin that hinges on low dissolution rates in ordinary organic solvents with meager yields [ 9 , 26 ], which could be a significant breakthrough but warrants further investigation.…”

“…Subsequent to the dripping of the lignin–DES solution into water, some highly hydrophobic lignin molecules could form a membrane at the two-phase interface between water and DES, causing water to be entrapped, and forming a balance between the continuous phase and the dispersed phase [ 9 ]. The lignin–DES solution will then be wrapped with the membrane.…”

“…A possible choice could be the production of nanoscale lignin, as increased surface area facilitates enhanced chemical and physical interactions of lignin [ 9 , 10 ]. Lignin nanoparticles (LNPs) could be prepared from various molecular sizes of soda lignin by the nanoprecipitation process with tetrahydrofuran (THF) [ 11 ].…”

Recent Advances in the Application of Functionalized Lignin in Value-Added Polymeric Materials

“…Applications of lignin nanoparticles in UV protection [ 121 ], antibacterial [ 122 ], mineral flotation [ 123 ], pickering emulsions [ 108 ], cosmetics [ 109 ], anticorrosion [ 124 ] and drug carriers have also been reported in the literature [ 112 ]. Wang et al prepared lignin nanoparticles via solvent exchange combined with the ultrasound process, and the UV adsorbing ability of these lignin nanoparticles was subsequently tested [ 109 ].…”