Preparation of Xanthan Nano Microgel and Its pH/Redox Responsiveness

Xanthan nano microgels with pH/redox responsiveness were prepared through an amidation reaction of xanthan in aqueous solution by "one pot" method using cystine hydrazide as the crosslinker. The structures and morphologies of the xanthan nano microgels were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Nuclear Magnetic Resonance (¹H-NMR), Dynamic Light Scattering (DLS), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). The properties and the drug controlled release of the nano microgels were investigated. Xanthan nano microgels had obvious pH and redox responsiveness. The free acyl groups of the microgels could react with ketone carbonyl groups of the doxorubicin, yielding pH sensitive acylhydrazone bonds. The disulfide bonds in cystamine tert-acylhydrazine could be reduced by glutathione solutions, leading to breakdown of the crosslinking structure and drug release. The nano microgels were biocompatible and they had promising prospects as anti-cancer drug carriers for targeted release.