Ratemo Bernadatte M, Wachira Benson M, Masika Eric, Ng'ang'a Margaret M, Hassanali Ahmed, Mireji Paul O
Department of Chemistry, Kenyatta University, Nairobi, Kenya.
Department of Chemistry, Pwani University, Kilifi, Kenya.
J Nanotechnol. 2025;2025(1). doi: 10.1155/jnt/6677970. Epub 2025 Mar 24.
Tsetse flies are major vectors of African trypanosomiasis, with devastating medical and veterinary consequences in sub-Saharan region of Africa. Insect repellents are promising tool for control of tsetse flies in the region. A four-component tsetse-repellent blend (δ-nonalactone, heptanoic acid, 4-methylguaiacol and geranyl acetone) previously formulated and optimized was encapsulated in β-cyclodextrin for a slow controlled release. Here, we explored various methods of microencapsulating (kneading, co-precipitation, heating or freeze-drying) tsetse fly repellent blend in β-cyclodextrin nanoparticles. We assessed release kinetics of the blends and individual compounds using Gas Chromatography linked with Flame Ionization Detector, and evaluated laboratory and field responses (repellence) of the flies by the encapsulated blends. We compared individual performances of releases kinetics of the encapsulated blend relative to non-encapsulated composites. Overall, kneading, co-precipitation, heating and freeze-drying micro-encapsulation techniques retained 72.0, 61.0, 59.5 and 57.3 % of the blend, respectively. Release rates of blends in 400- and 200-microns thick polythene sachets were 6.73 and 11.82 mg/h respectively, significantly (<0.05) higher than that of the kneaded encapsulated blend (5.35mg/h). Laboratory and field responses of tsetse flies to the unencapsulated native (sachet) and kneaded encapsulated odor blends confirmed our laboratory findings. Micro-encapsulation technology of repellent odors can be used for controlled release of active molecules in order to give an extended protection period, potentially reducing operational cost in programs for control of tsetse flies and related insect vectors.
采采蝇是非洲锥虫病的主要传播媒介，在非洲撒哈拉以南地区造成了毁灭性的医学和兽医后果。驱虫剂是该地区控制采采蝇的一种有前景的工具。先前配制和优化的一种四成分采采蝇驱避剂混合物（δ-壬内酯、庚酸、4-甲基愈创木酚和香叶基丙酮）被包封在β-环糊精中以实现缓慢的控释。在此，我们探索了将采采蝇驱避剂混合物微囊化（捏合、共沉淀、加热或冷冻干燥）到β-环糊精纳米颗粒中的各种方法。我们使用与火焰离子化检测器联用的气相色谱法评估了混合物和单个化合物的释放动力学，并通过包封的混合物评估了采采蝇的实验室和野外反应（驱避性）。我们比较了包封混合物相对于未包封复合物的释放动力学的个体性能。总体而言，捏合、共沉淀、加热和冷冻干燥微囊化技术分别保留了混合物的72.0%、61.0%、59.5%和57.3%。在400微米和200微米厚的聚乙烯小袋中混合物的释放速率分别为6.73毫克/小时和11.82毫克/小时，显著（<0.05）高于捏合包封混合物的释放速率（5.35毫克/小时）。采采蝇对未包封的天然（小袋）和捏合包封气味混合物的实验室和野外反应证实了我们的实验室发现。驱避气味的微囊化技术可用于活性分子的控释，以延长保护期，有可能降低采采蝇及相关昆虫传播媒介控制项目的运营成本。
