Synthesis and characterization of Ag/Co/chloroquine/cyclodextrin inclusion complex nanomaterials

Silver/chloroquine/β-cyclodextrin (Ag/CQ/β-CD) and silver/cobalt/chloroquine/β-cyclodextrin (Ag/Co/CQ/β-CD) inclusion complexes were synthesized and analyzed by UV­Visible absorption, fluorescence, FT­IR, DSC, PXRD, FE-SEM-EDAX, HR-TEM-EDS, modeling studies and antibacterial activity. A single emission maximum was observed for pure CQ in solvents, while an additional emission peak was observed in the presence of α-CD and β-CD due to the formation of an inclusion complex. In the CD solution, absorption and emission intensities increased upon formation of the inclusion complex, due to an increase in the rigidity of the system. The negative energy, enthalpy and Gibbs free energy changes suggested that the inclusion processes were spontaneous and enthalpically favorable in nature. The addition of Ag and Ag/Co nanoparticles to the CQ/CD inclusion complexes led to significant changes in the absorption and emission spectra, consistent with partial inclusion of the metallic nanoparticles in the CD. XRD and TEM studies confirmed the inclusion complexes were less than 50 nm in size. The antibacterial activity of Ag/CQ/β-CD and Ag/Co/CQ/β-CD was found to be lower than that of CQ, providing further evidence of its immobilization within the inclusion complex and its associated low bioavailability.