Green Chemistry Oriented Pluronic F127/Carbopol Nanogel Platform (NGLp) Encapsulating <em>L. pedunculosa </em>Essential Oil for <em>A. aegypti</em> Larval Control

Background/Objectives:A. aegypti larval control is essential for reducing arbovirus transmission; however, increasing insecticide resistance and environmental concerns demand sustainable alternatives. This study reports the development of a solvent-free, thermoresponsive Pluronic F127/Carbopol 974P nanogel (NGLp) encapsulating Lippia pedunculosa Hayek essential oil (OELp) to enhance larvicidal performance through improved dispersion and controlled release (Figure ). Methods: OELp was obtained by hydrodistillation and chemically characterized by GC–MS and NMR. Nanogels were prepared using a low-energy cold method (F127 20% w/w; Carbopol 0.2% w/w), selecting the most stable formulation (1% w/w OELp). The system was characterized by FTIR, dynamic light scattering (DLS), zeta potential, and scanning electron microscopy (SEM). Larvicidal activity was evaluated against third-instar A. aegypti larvae (20–60 μg mL−1; 24, 48, and 72 h), and LC50/LC90 values were estimated by logistic fitting. Results: OELp contained 28 identified constituents (96.65%), predominantly rotundifolone (62.68%) and limonene (20.74%), with NMR confirming rotundifolone as the major compound. The optimized nanogel exhibited nanometric size (239.9 nm; PdI 0.474) and a negative zeta potential (−22.3±3.90 mV), indicating electrosterically stabilized dispersion. FTIR confirmed physical incorporation of OELp. The nanogel demonstrated dose- and time-dependent larvicidal activity, achieving 100% mortality at ≥50 μg mL−1 (48–72 h). Mortality at intermediate concentrations increased over time (e.g., 53% at 30 μg mL−1 at 72 h), indicating sustained release. LC50/LC90 values decreased from 38.6/46.0 μg mL−1 (24 h) to 31.6/40.9 μg mL−1 (48 h), with further improvement at 72 h. Conclusions: NGLp enhances larvicidal performance through improved dispersion and sustained release of OELp, supporting its potential as a sustainable and eco-compatible nanoplatform for mosquito control.