基于贵金属/聚合物多重响应杂化空心微球的构筑与性能研究

Stimuli-responsive hybrid hollow spheres can respond the external environment factors quickly and have many advantages including large specific surface area, low density and good permeability. Therefore they show the important application prospects in many fields, such as, drug delivery, nanoreactors and the encapsulation of active molecules and so on. However, the preparation methods are complex and the impurity can easily be incorporated into the final products. Meanwhile, few studies about the preparation of noble metal nanoparticles/polymer multi-responsive hybrid hollow spheres have been reported. In this project, the hollow gel spheres can be firstly obtained via an inverse W/O microemulsion polymerization. During the process, the monomers can be polymerized on the water-oil interface to form phase separation depending on the LCST characters of thermal responsive polymer chains. The noble metal ions existing in the hydrogel shell by the electrostatic interaction or coordination bond can be reduced to nanoparticles, which will be used as the nanocrystal seeds for the in-situ controllable growth of noble metal nanoparticles. The formation mechanism of the noble metal nanoparticles/polymer multi-responsive hybrid hollow spheres will be established. The effect of the microstructures of the multi-responsive hybrid hollow spheres on their surface enhanced Raman spectroscopy properties and controlled-release ability would be further studied. The relationship among the composition-structure-properties and the rules of the multi-responsive hybrid hollow spheres would be revealed. The simple preparation route of these novel multi-responsive hybrid hollow spheres would be developed. This would provide the scientific basis for the application of biological detection and antibacterial in the future.

刺激响应杂化空心微球对外部环境因素快速响应，具有比表面积大、密度低和表面渗透性好的优点，在药物控释、纳米反应器和活性分子包覆等方面具有重要应用前景；但现有杂化空心微球制备方法复杂，易引入杂质；且基于贵金属/聚合物多重响应杂化空心微球的制备更是鲜见报道。本项目拟采用反相微乳液聚合法，利用温敏聚合物分子链段在温度低于最低临界溶液温度（LCST）时亲水，高于LCST时疏水的特点，使反应单体在油水界面聚合发生相分离一步形成空心凝胶微球。再将借助静电作用或配位键存在于壳层的贵金属离子还原成纳米晶种，进而调控贵金属纳米颗粒在凝胶壳层中的原位生长，构建多重响应杂化空心微球。深入系统研究这类杂化空心微球微观结构对其表面增强拉曼散射和客体分子控释能力的影响，揭示其组成-结构-性能的相关性及其调控规律，发展简便的新型多重响应杂化空心微球的制备路线，为发展其在生物检测和抗菌等领域的应用提供科学依据。

环境刺激响应性杂化空心微球具有比表面积大、密度低、表面渗透性好，以及对外界环境因素快速响应的特点，在活性物包覆领域具有重要应用前景。本项目基于油水界面作用，首先制备了环境刺激响应性聚合物空心微球，并利用该空心微球表面的活性基团通过原位还原法在聚合物网络中直接调控贵金属纳米颗粒的生长，最终制备了具有温度、pH、氧化还原和光热等多重环境刺激响应性的系列杂化空心微球，具体性能如下: 1)平均粒径370nm、临界溶解温度36︒C的P(NIPAM-AM)/AuNRs杂化空心凝胶球可用于负载阿霉素(DOX)，其负载率为26.27%。在近红外激光照射下，P(NIPAM-AM)/AuNRs杂化空心凝胶球24h累积释放率为76.79%，较未照射提高了28.08%，具有显著的光热效应。2)平均粒径532nm的柠檬醛@TA-Fe/AgNPs杂化空心微球对柠檬醛负载率为12.79%，具有良好的pH响应性和抑菌性能。在532nm下柠檬醛@TA-Fe/AgNPs杂化空心微球对10-3MR6G具有增强的拉曼特征峰。用于对金黄色葡萄球菌和大肠杆菌进行检测，其最低检测限均为105CFU/mL。3)平均粒径277nm的Ci@PDA/AgNPs杂化空心微球对Ci负载率为29.28%，在近红外光照射下，Ci在300min累计释放了27.32%，较无近红外光照射下提高了17.07%；抑菌率可达100%。此外，还扩展性地通过溶胶-凝胶法制备有机-无机介孔二氧化硅微球，以其为载体负载香料，并在其表面包覆环境响应性聚合物，最终制备了pH-氧化还原双重响应性Ci@D-MONs@CS纳米颗粒。当pH6.5、GSH浓度为10mM时，Ci@D-MONs@CS在12h累计释放率较pH7.4下提高了22.3%，可有效抑制细菌，改善不良气味。进一步制备了平均粒径为280nm的光响应性OF@TMSiO2-AZONPs。将OF@TMSiO2-AZONPs应用于皮革涂饰加香，可有效改善皮革不良气味。本项目研究成果改善了传统微纳胶囊的释放方式，实现了功效物质在不同因素刺激下的智能可控释放，已应用于具有芳香、抗菌、防紫外和防水等功能性皮革的开发，在海宁森德皮革和上海水星家纺等公司开展产业化推广，扩展了环境刺激响应性杂化空心微球的应用领域，对传统皮革产业的升级换代和可持续性发展具有重要意义。