Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman, B6a, 4000 Liège, Belgium.
Chem Asian J. 2010 Apr 1;5(4):859-68. doi: 10.1002/asia.200900277.
Well-defined poly(vinyl acetate) (PVAc) and poly(N-vinylpyrrolidone)-co-poly(vinyl acetate) (PNVP-co-PVAc) chains end-capped by Co(acac)(2) (acac=acetylacetonate) and prepared by cobalt-mediated radical polymerization (CMRP) are grafted onto a fullerene. Homolytic Co-C bond cleavage of the polymer chain ends at 30 degrees C releases the polymeric radicals that add onto C(60), thereby leading to the corresponding PVAc/C(60) and PNVP-co-PVAc/C(60) nanohybrids. The [polymer-Co(acac)(2)]/[C(60)] molar ratio was varied to adjust the structure of the nanohybrids, and more particularly the number of grafted arms. Finally, the potential of the hydrosoluble PVOH/C(60) nanohybrids, which result from the methanolysis of the ester groups of PVAc/C(60), and of the PNVP-co-PVAc/C(60) nanohybrids as photosensitizers for photodynamic therapy (PDT), was approached. First, photobleaching tests demonstrated the ability of these nanohybrids to produce singlet oxygen upon irradiation, which can play a role in cell damage. Second, cell viability assays demonstrated that both types of nanohybrids are deprived of intrinsic cytotoxicity in the dark, whereas they promoted significant cell mortality when subjected to light treatment. The selective response of these materials to irradiation makes them promising compounds for PDT.
端基被 Co(acac)(2)（acac=乙酰丙酮根）封端的、通过钴介导的自由基聚合（CMRP）制备的、具有明确结构的聚（醋酸乙烯酯）（PVAc）和聚（N-乙烯基吡咯烷酮）-共-聚（醋酸乙烯酯）（PNVP-co-PVAc）链被接枝到富勒烯上。在 30°C 时，聚合物链末端的均裂 Co-C 键断裂，释放出的聚合自由基加成到 C(60)上，从而得到相应的 PVAc/C(60)和 PNVP-co-PVAc/C(60)纳米杂化物。通过改变[聚合物-Co(acac)(2)]/[C(60)]摩尔比来调整纳米杂化物的结构，特别是接枝臂的数量。最后，研究了通过 PVAc/C(60)酯基的甲醇解得到的水溶性 PVOH/C(60)纳米杂化物以及 PNVP-co-PVAc/C(60)纳米杂化物作为光动力疗法（PDT）光敏剂的潜力。首先，光漂白测试表明这些纳米杂化物在光照下能够产生单线态氧，从而在细胞损伤中发挥作用。其次，细胞活力测定表明，这两种纳米杂化物在黑暗中都没有固有细胞毒性，而在光处理下则促进了显著的细胞死亡。这些材料对辐照的选择性响应使它们成为 PDT 的有前途的化合物。
