Pluronic-based nano-carriers including bare forms that were composed of
Pluronic F 68(NC(PF 68)) or
Pluronic F 127(NC(PF 127)), and
chitosan-conjugated forms (Chito-NC(PF 68) or Chito-NC(PF 127)) were prepared by photo-polymerizing two kinds of diacrylated
Pluronic (F 68 and F 127) and acrylated
chitosan to investigate the effect of
chitosan conjugation and their physicochemical characteristics (size and hydrophilicity) of
Pluronic-based nano-carriers on the
tumor targeting efficiency. All of the nano-carriers were stable in serum-containing media without forming any aggregation and did not show any acute cytotoxicity to both normal (NIH3T3 fibroblast) and
tumor (SCC7) cells.
Chitosan conjugation did not change their sizes or thermo-sensitive properties of the nano-carriers, but significantly increased their in-vitro cellular uptake compared to the corresponding bare forms. The in-vivo
tumor accumulation of these nano-carriers was optically monitored by using Cy5.5-attached nano-carriers in SCC7
tumor-bearing mice. For all cases, local accumulation of the injected nano-carriers in liver was not dominant compared to the
tumor site, demonstrating good
tumor targeting efficacy of the
Pluronic-based nano-carriers. Among different samples,
chitosan-conjugated nano-carriers showed much better
tumor accumulation than bare forms, and mostly remained up to 72h, implying prolonged blood circulation and more efficient
tumor accumulation. Between Chito-NC(PF 68) and Chito-NC(PF 127), Chito-NC(PF 68) showed a little better
tumor accumulation and retention, suggesting the difference in
Pluronic, thus difference in hydrophilicity and the size of the nano-carriers also might affect the
tumor targeting. In contrast, bare nano-carriers were initially accumulated well in
tumor, but they were excreted from the
tumor site relatively rapidly. Therefore,
chitosan-functionalization was very effective for improving the
tumor targeting efficacy of
Pluronic-based nano-carriers.