多效唑纳米微球悬浮液的制备及性质研究

Preparation and characterization of paclobutrazol nanospheres suspension concentrate

相较于传统农药,纳米农药能够增强农药在作物叶片表面的附着力和铺展性。通过壳聚糖与玉米醇溶蛋白静电自组装制备了多效唑(PBZ)的纳米微球(CS/zein-PBZ NPs)悬浮液。基于负载多效唑的纳米微球,测定了微球的平均粒径、电位、包埋率、载药量、稳定性、缓释性能以及载药微球在叶面上的铺展性。多效唑纳米微球通过扫描电子显微镜(SEM)测得的平均粒径为(187±46) nm。动态光散射(DLS)测量微球平均粒径为170~320 nm,多分散系数(PDI)为0.3左右。微球表面带有正电荷,zeta电位为(68.7±0.7) m V。微球包埋率和载药量最高分别达到89.9%和28.8%。微球具有较好的储存稳定性,在热贮(54℃)条件下保存14 d粒径基本保持不变。多效唑纳米微球具有缓释性能,能够有效提高多效唑利用率。与多效唑可湿性粉剂相比,多效唑纳米微球悬浮液的接触角更低,证明它具有更强的铺展性,可以促进与叶片表面的相互作用,以提高其铺展性和润湿性。

Compared with conventional pesticides, nanospheres can enhance the adhesion and diffusion of pesticides on crop leaf surface. In this study, composite nanospheres suspension concentrate of paclobutrazol(PBZ) were constructed by electrostatic self-assembly of chitosan(CS) and zein. The average size, potential, encapsulation efficiency, loading efficiency, stability, control released ability and spreading property of PBZ-loaded nanospheres(CS/zein-PBZ NPs) were determined. The resulting CS/zein-PBZ NPs were in the average size of(187 ± 46) nm measured by scanning electron microscope(SEM). Dynamic light scattering(DLS) measures the average particle size of CS/zein-PBZ NPs in the range of170-320 nm and the polydispersity(PDI) was around 0.3. Meanwhile, the zeta potential of CS/zein-PBZ NPs was(68.7 ± 0.7) m V,indicating that the particle surface contained a positive charge. The encapsulation efficiency and loading efficiency of nanospheres reached 89.9% and 28.8%, respectively. Moreover, the CS/zein-PBZ NPs can maintain stable for at least 14 d at 54 ℃. The CS/zein-PBZ NPs have control released ability, which can effectively improve the utilization of PBZ.Compared with PBZ wettable powder(PBZ WP), the contact angle of CS/zein-PBZ NPs was lower, which proved that it has stronger spreading property and can promote the interaction with leaf surface to improve its spreading and wettability.