Crosslinking of biodegradable polymers is potentially important to control swelling and degradation rates. The earliest work in chitosan nanostructures predominantly involved chemical cross-linking reactions to the polymer chain. Watzke et al. formed chitosan-silica nanocomposites by reacting tetramethoxysilane to the hydroxyl groups on the chitosan monomer [48]. However, attempts were not made to associate active agents to the polymer network. Ohya et al. was the first to present data involving chitosan nanospheres for the drug 5-fluorouracil (5- FU) delivery applications, using a water-in-oil emulsion method followed by glutaraldehyde cross-linking of the chitosan amino groups [49]. Yao et al. have prepared an...