Long-term and controlled release of chlorhexidine–copper(II) from organically modified montmorillonite (OMMT) nanocomposites

Drug/metal ion complexes exhibit improved antimicrobial activity and intercalating the above complexes into the interlayer of clay endows a long-term and controlled-release behavior. In this study, chlorhexidine was first complexed with copper (II) ion and then intercalated into the interlayer of MMT to form chlorhexidine–copper (II)/montmorillonite (CHX–Cu/MMT) nanocomposites. The nanocomposites were characterized with Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). A nearly lateral-monolayer arrangement of CHX–Cu was supposed for the intercalation. Release kinetics indicated that the release process satisfied a pseudo-second-order mode. The antibacterial results showed that the CHX–Cu/MMT composites had long-term and controlled-release behavior. - Graphical abstract: The antibacterial agent of chlorhexidine was first complexed with copper(II) chloride and then intercalated into the interlayer of MMT to form nanocomposites. The CHX–Cu/MMT composites exhibited long-term antibacterial activity and controlled release behaviors. Highlights: ► Chlorhexidine–copper (II)/montmorillonite (CHX–Cu/MMT) complex exhibits improved antimicrobial activity. ► Intercalating chlorhexidine–copper (II) complex into the interlayer of clay endows a long-term and controlled-release. ► Release kinetics indicated that the release process satisfied a pseudo-second-order mode. ► A nearly lateral-monolayer arrangement of CHX–Cu was supposed for the intercalation.