Evaluation of CPP and LDH nanocarriers for dsRNA efficiency in Brassicogethes aeneus

This study evaluates two nanocarrier systems, clay-based magnesium-aluminum layered double hydroxide (MgAl-LDH) and the cell-penetrating peptide PepFect14 (PF14), for delivering double-stranded RNA (dsRNA) targeting the αCOP gene in Brassicogethes aeneus. Both carriers successfully formed stable complexes and protected dsRNA from degradation under simulated gut conditions. PF14 produced small, uniform nanoparticles (<120 nm), whereas MgAl-LDH generated substantially larger particles (~416 nm), potentially limiting cellular uptake. Feeding assays revealed that naked dsRNA caused high mortality (93% by day 12), while PF14-complexed dsRNA induced substantial mortality (70%) with a delayed onset. In contrast, MgAl-LDH-complexed dsRNA achieved only 22% mortality despite providing strong protection against degradation. mRNA expression analysis at day 3 and 6 showed moderate, statistically insignificant early αCOP downregulation, consistent with delayed intracellular processing. At higher concentrations (600 ng/µL), naked dsRNA strongly suppressed αCOP transcripts (100%), whereas MgAl-LDH complexes produced only modest knockdown (63.6%). Overall, these findings suggest that while MgAl-LDH offer robust dsRNA stabilization, its delivery efficiency may be constrained by particle size and gut physiology. PF14 demonstrates promise as a carrier enabling sustained delivery with delayed onset, whereas MgAl-LDH requires higher dsRNA doses to achieve comparable effects. Carrier selection should balance dsRNA stability with timely release and account for species-specific gut barriers to optimize RNAi-based pest control strategies.