Thermo-sensitive core–shell nanoparticles as potential drug carrier

Using fluorescence spectrometry, it was found pyrene begins to partition into the core of poly(ε-caprolactone)/poly(N-isopropylacrylamide) (PCL/PNIPAM) core–shell nanoparticles at a low nanoparticle concentration (0.001 mg/mL). The partition coefficient for pyrene partitioning between water and the nanoparticles is around 104. The rate for pyrene partitioning into PCL core is very quick, depending on the relative PCL core weight. And the distinct on–off property of the nanoparticle with temperature was revealed: pyrene molecules enter into PCL core freely when temperature is less than 34 °C; while it becomes difficult when temperature rises to 37 °C. In addition, a new procedure to accurately determine the loading capacity of nanoparticle core for hydrophobic compound using UV–vis spectrometry was developed.