Enhanced Bioactivity of Botanical Acaricidal Compound-Scopoletin Encapsulated by Polydopamine and Cellulose Nanocrystals Against Carmine Spider Mite

Abstract

Background Scopoletin (Sco) is a botanical acaricidal compound isolated and purified from Artemisia annua. Self-assembled nanostructured materials with tailored properties could aid efficient acaricide delivery. Methods The botanical natural product Sco was coated on the surface of cellulose nanocrystals (CNCs) and polydopamine (PDA) to enhance its acaricidal bioactivity. Sco@PDA-CNCs, a new biological base acaricidal agent, were prepared through hydrogen bonding and van der Waals forces. Result Sco@PDA-CNCs exhibited a stronger acaricidal effect than pure Sco. At 48 h after treatment, the median lethal concentration of Sco@PDA-CNCs against carmine spider mites was 24.36 mg/L and that of pure Sco was 92.21 mg/L. The toxicity value of Sco@PDA-CNCs had increased by 3.8-fold relative to that of pure Sco. Sco@PDA-CNCs exhibited sustained release characteristics and continued to release Sco even at 7 days after application. Conclusion Results revealed that Sco@PDA-CNCs not only have good slow-release properties, but they can also improve acaricidal efficiency well.