纳米金刚石/酵母-壳聚糖复合微球的制备及光热控释性能

开发高性能功能性光热凝胶并建立药物控释模型对农药智能输送材料的开发具有重要意义。以酵母-壳聚糖水凝胶(YS-CS)为基体，引入光热材料纳米金刚石(DND)，通过碱凝胶法合成了纳米金刚石/酵母-壳聚糖(DND/YS-CS)交联网络结构复合凝胶微球，研究了复合微球的微观结构、力学性能和光热转换性能；以吲哚丁酸(IBA)为模型药物，探讨DND/YS-CS对IBA的负载性能和控释性能，揭示复合微球对IBA的光热控释机制。结果表明：复合微球具有良好的力学性能，在分别超声和离心1 h后，DND含量为2.0 mg/mL复合微球保水能力分别达到70.5%和74%；复合微球具有良好的光热转换能力，一个太阳光强度下，最高温度可达37.6℃；DND含量为1.2 mg/mL复合微球对IBA的吸附量最高，可达到41.73μg/mg；微球在光下药物释放模式符合Korsmeyer-Peppas模型，在光下具有明显的刺激响应行为，药物释放呈现“开-关”模式。通过控制光的照射强度控制药物释放，在农业领域有广阔的应用前景。

Preparation and photo-thermal controlled release properties of nanodiamond/yeast-chitosan composite microspheres

It is important to develop high-performance functional photo-thermal materials and establish controlled drug release models for the development of intelligent transportation materials for pesticides. Herein, nanodiamond (DND) was employed to prepare novel nanodiamond/yeast-chitosan (DND/YS-CS) composite hydrogel microspheres which had a cross-linked network structure through alkali gelation method. The microstructure, mechanical resistance and photo-thermal conversion performance of the composites were investigated. Moreover, indole-3-butyric acid (IBA) was used as a model to discuss the loading and controlled drug release and reveal the photo-thermal controlled release mechanism of IBA by DND/YS-CS. The results show that the composite microspheres has good mechanical properties, and the water retention capacity of the composite microspheres with DND content of 2.0 mg/mL reached 70.5% and 74% after ultrasonication and centrifugation for 1 h, respec-tively. The maximum temperature of the composites can reach to 37.6℃ under one sunlight intensity, proving that the composites possess excellent photothermal conversion ability. The maximum adsorption of IBA is 41.73 μg/mg when the composites have a DND concentration of 1.2 mg/mL. Finally, the controled drug release pattern of the composites is in accordance with the Korsmeyer-Peppas model, which exhibits an obvious stimulus response behavior and an "on-off" pattern of drug release under light.