College of Environmental Science and Engineering, Chang'an University , Xi'an 710054, P. R. China.
State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University , Xining 810001, P. R. China.
ACS Appl Mater Interfaces. 2017 Feb 22;9(7):6424-6432. doi: 10.1021/acsami.6b15393. Epub 2017 Feb 8.
Controlled stimuli-responsive release systems are a feasible and effective way to increase the efficiency of pesticides and help improve environmental pollution issues. However, near-infrared (NIR)-responsive systems for encapsulation of pesticides for controlling release have not been reported because of high cost and load ability of conventional NIR absorbers as well as complicated preparation process. Herein, we proposed polydopamine (PDA) microspheres as a photothermal agent owing to their abundant active sites, satisfactory photothermal efficiency, low cost, and easy fabrication, followed by capping with a PNIPAm thermosensitive polymer shell. In this core-shell PDA@PNIPAm hybrid system, the PDA core provided excellent temperature and NIR-light sensitivity as well as high loading capacity, while the PNIPAm applied as both a thermosensitive gatekeeper and a pesticide reservoir. The structure of the PDA@PNIPAm nanocomposites was characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, dynamic light scattering, and thermogravimetric analysis; the results showed that the nanocomposites had a well-defined core-shell configuration for efficient loading of small pesticide molecules. Moreover, the core-shell PDA@PNIPAm nanocomposites exhibited high loading capacity and temperature- or NIR-controlled release performance. Overall, this system has significant potential in controlled drug release and agriculture-related fields as a delivery system for pesticides with photothermal responsive behavior.
受控制的刺激响应释放系统是提高农药效率并有助于改善环境污染问题的一种可行且有效的方法。然而，由于常规近红外（NIR）吸收剂的成本高和负载能力以及复杂的制备工艺，用于封装农药以控制释放的近红外响应系统尚未见报道。在此，我们提出了聚多巴胺（PDA）微球作为光热剂，因为其具有丰富的活性位点、令人满意的光热效率、低成本和易于制造，随后用 PNIPAm 热敏聚合物壳进行覆盖。在这种核壳 PDA@PNIPAm 杂化系统中，PDA 核提供了出色的温度和 NIR 光敏感性以及高负载能力，而 PNIPAm 既用作热敏门控剂又用作农药储库。通过透射电子显微镜、扫描电子显微镜、傅里叶变换红外光谱、紫外可见光谱、动态光散射和热重分析对 PDA@PNIPAm 纳米复合材料的结构进行了表征；结果表明，纳米复合材料具有定义明确的核壳结构，可有效负载小分子农药。此外，核壳 PDA@PNIPAm 纳米复合材料表现出高负载能力和温度或 NIR 控制的释放性能。总体而言，作为具有光热响应行为的农药的递送系统，该系统在控制药物释放和农业相关领域具有重要的应用潜力。
