Acaricidal activities of clove bud oil and red thyme oil using microencapsulation against HDMs

The purpose of this study was to produce a safer microcapsule loaded with clove bud oil and red thyme oil to reduce the population of house dust mites (HDMs). Gelatin-based microcapsules 4-85 µm in size were created, with agitation speed and type of oil playing a critical role in governing their size. Microcapsules made up of single spherical units less than 30 µm in diameter remained separate on the fibre, whereas larger microcapsules of over 30 µm ruptured or aggregated. Thermogravimetric analysis (TGA) demonstrated that microcapsules containing red thyme oil showed a more consistent range of oil loading, from 50 to 80%, than microcapsules containing clove bud oil, which ranged from 30 to 80% (more deviated). Mortality tests on Dermatophagoides farinae conducted on fabric with attached microcapsules showed that clove bud oil, containing a more phenolic monoterpenoid (eugenol), was more effective at reducing the live HDMs (94% mortality).