Antibacterial and Cytotoxic Activities of Copper-Functionalized Silsesquioxane 3-n-Propylpyridinium Chloride

Silsesquioxane 3-n-propylpyridinium chloride (SiPy+Cl-) is a water-soluble polymer that can be used as a promising material with remarkable biological effects. SiPy+Cl- can form thin films on substrate surfaces and shows suitable adhesiveness. Besides, it has high affinity for metal ions. Considering this effect as exchanger polymer and the well-known antimicrobial and cytotoxic features of copper, the aim of this study was to perform the copper functionalization of silsesquioxane 3-n-propylpyridinium chloride Cu-SiPy+Cl-. The SiPy+Cl- was obtained by the sol-gel processing method and the incorporation of copper (II) chloride was carried out by immobilization. Its characterization was performed by spectroscopic methods of Fouriertransform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The FTIR spectrum of SiPy+Cl- showed symmetric and asymmetric stretching of Si-O-Si group and also exhibited vibrational bands of pyridinium ring. The FTIR spectrum of Cu-SiPy+Cl- assigned typical bands displacements of the metal coordination to nitrogen atoms. Spectroscopic data recorded by C-13 and S-29 NMR confirmed the chemical structures of SiPy+CI- and Cu-SiPy+Cl-. Concerning to the in vitro susceptibility assay, the antimicrobial activity against Staphylococcus aureus, Escherichia coli and Streptococus mutans was achieved by the agar-well diffusion method. Cu-SiPy+Cl- showed similar cytotoxicity than SiPy+Cl- against Calu-3 and 3T3 cell lines by the MTT colorimetric assay. Further studies are required to investigate the use of Cu-SiPy+Cl- as a novel dental material.