Materials and Nanotechnology Program, North Dakota State University, Fargo, North Dakota 58108, United States.
Department of Mechanical Engineering, North Dakota State University, Fargo, North Dakota 58108, United States.
ACS Appl Bio Mater. 2023 Jul 17;6(7):2698-2711. doi: 10.1021/acsabm.3c00171. Epub 2023 Jul 5.
In this report, two polymeric matrix systems at macro and nanoscales were prepared for efficacious fungicide delivery. The macroscale delivery systems used millimeter-scale, spherical beads composed of cellulose nanocrystals and poly(lactic acid). The nanoscale delivery system involved micelle-type nanoparticles, composed of methoxylated sucrose soyate polyols. (Lib.), a destructive fungus affecting high-value industrial crops, was used as a model pathogen against which the efficacy of these polymeric formulations was demonstrated. Commercial fungicides are applied on plants frequently to overcome the transmission of fungal infection. However, fungicides alone do not persist on the plants for a prolonged period due to environmental factors such as rain and airflow. There is a need to apply fungicides multiple times. As such, standard application practices generate a significant environmental footprint due to fungicide accumulation in soil and runoff in surface water. Thus, approaches are needed that can either increase the efficacy of commercially active fungicides or prolong their residence time on plants for sustained antifungal coverage. Using azoxystrobin (AZ) as a model fungicide and canola as a model crop host, we hypothesized that the AZ-loaded macroscale beads, when placed in contact with plants, will act as a depot to release the fungicide at a controlled rate to protect plants against fungal infection. The nanoparticle-based fungicide delivery approach, on the other hand, can be realized via spray or foliar applications. The release rate of AZ from macro- and nanoscale systems was evaluated and analyzed using different kinetic models to understand the mechanism of AZ delivery. We observed that, for macroscopic beads, porosity, tortuosity, and surface roughness governed the efficiency of AZ delivery, and for nanoparticles, contact angle and surface adhesion energy were directing the efficacy of the encapsulated fungicide. The technology reported here can also be translated to a wide variety of industrial crops for fungal protection. The strength of this study is the possibility of using completely plant-derived, biodegradable/compostable additive materials for controlled agrochemical delivery formulations, which will contribute to reducing the frequency of fungicide applications and the potential accumulation of formulation components in soil and water.
在本报告中，我们制备了两种聚合物基质系统，分别在宏观和纳米尺度上用于高效杀菌剂的输送。宏观输送系统使用毫米级、由纤维素纳米晶和聚乳酸组成的球形珠粒。纳米输送系统涉及胶束型纳米粒子，由甲氧基化蔗糖大豆醇聚酯组成。（Lib.）是一种破坏性真菌，影响高价值工业作物，被用作模型病原体，以证明这些聚合物配方的功效。商业杀菌剂经常被施用于植物上，以克服真菌感染的传播。然而，由于环境因素如降雨和气流，杀菌剂在植物上不会长时间持续存在。需要多次施药。因此，由于杀菌剂在土壤中积累和地表水的径流，标准的应用实践会产生显著的环境足迹。因此，需要采取措施来提高商业活性杀菌剂的功效或延长其在植物上的停留时间，以实现持续的抗真菌覆盖。我们使用肟菌酯（AZ）作为模型杀菌剂，油菜作为模型作物宿主，假设接触植物时，负载 AZ 的宏观珠粒将作为一个储存库，以控制速率释放杀菌剂，以保护植物免受真菌感染。另一方面，基于纳米粒子的杀菌剂输送方法可以通过喷雾或叶面施用来实现。通过使用不同的动力学模型来评估和分析 AZ 从宏观和纳米尺度系统的释放速率，以了解 AZ 输送的机制。我们观察到，对于宏观珠粒，孔隙率、曲折度和表面粗糙度控制着 AZ 输送的效率，而对于纳米粒子，接触角和表面粘附能指导封装杀菌剂的功效。这里报道的技术也可以转化为广泛的工业作物，用于真菌保护。本研究的优势在于，可以使用完全源自植物、可生物降解/可堆肥的添加剂材料来制备用于控制农用化学品输送配方的材料，这将有助于减少杀菌剂的应用频率以及配方成分在土壤和水中的潜在积累。
