Budhlall Bridgette M, Marquez Manuel, Velev Orlin D
NSF funded Center for High-Rate Nanomanufacturing and Nanomanufacturing Center of Excellence, Department of Plastics Engineering, University of Massachusetts, Lowell, Massachusetts 01854, USA.
Langmuir. 2008 Oct 21;24(20):11959-66. doi: 10.1021/la8019556. Epub 2008 Sep 26.
Microwave-, photo- and thermo-responsive polymer microgels that range in size from 500 to 800 microm and are swollen with water were prepared by a novel microarray technique. We used a liquid-liquid dispersion technique in a system of three immiscible liquids to prepare hybrid PNIPAm- co-AM core-shell capsules loaded with AuNPs. The spontaneous encapsulation is a result of the formation of double oil-in-water-in-oil (o/w/o) emulsion. It is facilitated by adjusting the balance of the interfacial tensions between the aqueous phase (in which a water-soluble drug may be dissolved), the monomer phase and the continuous phase. The water-in-oil (w/o) droplets containing 26 wt% NIPAm and Am monomers, 0.1 wt% Tween-80 surfactant, FITC fluorescent dye and colloidal gold nanoparticles spontaneously developed a core-shell morphology that was fixed by in situ photopolymerization. The results demonstrate new reversibly swelling and deswelling AuNP/PNIPAm hybrid core-shell microcapsules and microgels that can be actuated by visible light and/or microwave radiation (<or=1,250 nm) and/or temperature. This is the first study to demonstrate that incorporating AuNPs speeds up the response kinetics of PNIPAm, and hence enhances the sensitivity to external stimuli of PNIPAm. These microgels can have potential applications for microfluidic switches or microactuators, photosensors, and various nanomedicine applications in controlled delivery and release.
通过一种新型微阵列技术制备了尺寸在500至800微米之间且用水溶胀的微波、光和热响应性聚合物微凝胶。我们在三种互不相溶的液体体系中采用液-液分散技术制备了负载金纳米颗粒的PNIPAm-co-AM杂化核壳胶囊。自发包封是双油包水包油（o/w/o）乳液形成的结果。通过调节水相（其中可溶解水溶性药物）、单体相和连续相之间的界面张力平衡来促进这一过程。含有26 wt% NIPAm和Am单体、0.1 wt%吐温80表面活性剂、FITC荧光染料和胶体金纳米颗粒的油包水（w/o）液滴自发形成核壳形态，并通过原位光聚合固定。结果表明，新的金纳米颗粒/PNIPAm杂化核壳微胶囊和微凝胶具有可逆的溶胀和去溶胀特性，可由可见光和/或微波辐射（≤1250 nm）和/或温度驱动。这是第一项证明掺入金纳米颗粒可加快PNIPAm的响应动力学，从而提高PNIPAm对外部刺激敏感性的研究。这些微凝胶在微流体开关或微致动器、光传感器以及可控递送和释放中的各种纳米医学应用方面具有潜在应用价值。
