Valorization of Kraft Lignin via Its Conversion into Lignin Nanoparticles to Act Both as DDS and Biostimulator for Plant

Lignin is the second most critical natural heteropolymer that has the potential to produce several value-added products. Around 85% of the lignin generated worldwide is produced as kraft lignin (KL), a type of industrial lignin obtained from kraft pulp. KL-containing effluents harm aquatic life, such as respiratory stress, liver damage, and genotoxicity. In this study, an attempt was made to create multifunctional lignin nanoparticles (LNP) using different solvents such as methanol, tetrahydrofuran (THF), ethylene glycol, DMSO, and 70% ethanol using KL and its application as drug delivery system was evaluated. The produced particles were characterized by dynamic light scattering (DLS), Zeta potential, FESEM, thermogravimetric analysis (TGA), XRD, and FTIR. The curcumin encapsulated LNP (LNP-C) was made (size > 99% < 300 nm, − 18.5 mV Zeta Potential, crystallite size of 7.9 nm, 10.6 nm, and 6.1 nm, lattice strain of 0.01496, 0.01593, and 0.02594) as a vehicle for drug delivery. The IC₅₀ value of LNP-C was determined to be 12.2803 ± 1.397 µg/ml. LNP’s role as DDS was found significant. Moreover, interestingly LNPs acted as a growth stimulator when examined using the Vigna radiata seed assay.