Poly(propylene imine) dendrimer-grafted nanocrystalline cellulose: Doxorubicin loading and release behavior

4th-generation poly(propylene imine) (PPI)-grafted nanocrystalline cellulose (NCC) is prepared via iterative Michael addition of acrylonitrile onto amine-functionalized NCC as initial core and homogeneous hydrogenation of nitrile groups to primary amines. Successful grafting of dendrimers onto NCCs is confirmed by TEM, FT-IR, XPS, TGA and elemental analyses. Also, peripheral primary amines of dendrimer-grafted NCCs are conjugated with folic acid (FA) to investigate bioconjugation effect on drug release behavior of nanostructures. FA-conjugated and nonconjugated nanostructures are loaded with DOX and exposed to environments with different pH values to examine release behavior. Also, drug release kinetics is studied by fitting of experimental data with release models. At different pH values, nonconjugated nanostructures show higher cumulative drug release than FA-conjugated systems while loading content was higher for conjugated systems. Drug release from nonconjugated nanostructures is modeled using Korsmeyer-Peppas model that describes release from polymeric matrix. However, in conjugated system, Higuchi model is the best one due to the better solubility of DOX in release media than cavities of grafted dendrimers. (C) 2017 Elsevier Ltd. All rights reserved.