Abstract

Two pH-responsive polysaccharide-based magnetite nano-carriers have been developed from modified salep and PEGylated chitosan decorated onto the surface of magnetite nanoparticles for active loading and targeted delivery of doxorubicin. The first nanocarrier was formed via imine bond formation and electrostatic hydrogen bonding interactions between dialdehyde salep-modified magnetite nanoparticles and DOX in a one-layered nanocarrier fashion. Subsequently, PEGylated chitosan was used as a second layer on the surface of the first nanocarrier, mainly by the same interactions, producing a double-layered polysaccharide-based nanocarrier. In vitro release studies indicated that the use of PEGylated chitosan as the second shell provides more control on the rate and amount of DOX release and makes double-layered nanocarrier more pH-sensitive. Magnetic heating capacity of double-layered nanocarrier was investigated and release profile under AMF (42 degrees C, magnetically induced) showed a good improvement in the time and amount of DOX release. In vitro MTT assays depicted that the DOX-loaded double-layered nanocarrier produces a large cytotoxic response to HeLa cells, which is comparable with free DOX in higher concentration. DOX-free double-layered nanocarrier also exhibited low cytotoxicity against normal cells, an indication of their excellent biocompatibility. Application of AMF also showed a large effect on the cytotoxicity of the nanocarrier rather than without AMF condition. Investigation on cellular uptake of nanocarrier revealed the high targeting ability of nanocarrier toward HeLa cells, especially in the presence of AMF. Blood compatibility investigations indicated that hemolysis of RBCs and coagulation times fall into the normal range for blood in the presence of DOX-free and DOX-loaded double-layered nanocarrier.