posted on 2024-03-01, 21:30authored byAlvaro Garcia, Carlos E. Astete, Rafael Cueto, Cristina M. Sabliov
An efficient and sustainable agriculture calls for the
development
of novel agrochemical delivery systems able to release agrochemicals
in a controlled manner. This study investigated the controlled release
of the insecticide methoxyfenozide (MFZ) from lignin (LN) nanoparticles
(LNPs). LN-grafted poly(ε-caprolactone) (LN-g-PCL) polymers were synthesized using two grafting methods, ring-opening
polymerization (ROP)(LN-g-PCLp) and acylation
reaction (LN-g-PCLa), creating polymers
capable of self-assembling into nanoparticles of different properties,
without surfactants. The LN-g-PCLp polymers
exhibited a degree of polymerization (DP) from 22 to 101, demonstrating
enhanced thermal stability after LN incorporation. LNPs loaded with
MFZ exhibited a spherical core–shell structure with a hydrophilic
LN outer layer and hydrophobic PCL core, with sizes affected by grafting
methods and DP. LNPs controlled MFZ release, displaying variation
in release profiles depending on the grafting methodology used, LN-g-PCLp DP, and temperature variations (23 to
30 °C). LNPs formulated with LN-g-PCLa showed a cumulative release of MFZ of 36.78 ± 1.23% over 196
h. Comparatively, increasing the DP of the LN-g-PCLp polymers, a reduction of the LNPs release rate from 92.39
± 1.46% to 70.59 ± 2.40% was achieved within the same time
frame. These findings contribute to identifying ways to modulate the
controlled release of agrochemicals by incorporating them in renewable-based
LNPs.