Lehmann Swen, Seiffert Sebastian, Richtering Walter
Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52074 Aachen, Germany.
F-ISFM Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany; Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 3, D-14195 Berlin, Germany.
J Colloid Interface Sci. 2014 Oct 1;431:204-8. doi: 10.1016/j.jcis.2014.06.014. Epub 2014 Jun 18.
The diffusion of payloads within core-shell carrier particles is of major relevance for drug-delivery applications. We use spatially resolved two-focus fluorescence correlation spectroscopy to quantify the diffusivity of different dextran molecules and colloids within carrier particles composed of a temperature-responsive poly(N-isopropylacrylamide) (PNIPAM) shell that surrounds a temperature-insensitive polyacrylamide core. The deswelling of the shell that occurs upon heating above the lower critical solution temperature of PNIPAM slightly slows down the diffusion of these tracer oligomers near the core-shell interface. By contrast, the mobility of the tracers inside the core is not affected by deswelling of the shell. This finding assures absence of artifacts such as adsorption of the guests to the amphiphilic shell polymer, supporting the utility of these microgel carriers in encapsulation and controlled release applications.
核壳载体颗粒内有效载荷的扩散对于药物递送应用至关重要。我们使用空间分辨双焦点荧光相关光谱法来量化不同葡聚糖分子和胶体在由温度响应性聚（N-异丙基丙烯酰胺）（PNIPAM）壳包围温度不敏感聚丙烯酰胺核组成的载体颗粒内的扩散率。当加热到高于PNIPAM的下临界溶液温度时壳的去溶胀会稍微减慢这些示踪低聚物在核壳界面附近的扩散。相比之下，核内示踪剂的迁移率不受壳去溶胀的影响。这一发现确保不存在诸如客体吸附到两亲性壳聚合物等假象问题，支持了这些微凝胶载体在包封和控释应用中的实用性。
