Modified montmorillonite nanosheets as a nanocarrier with smart pH-responsive control on the antimicrobial activity of tetracycline upon release

Abstract

In this study, montmorillonite nanosheets were used in order to control the release pattern of tetracycline based on the pH and to control its antimicrobial activity upon release. The tetracycline was adsorbed onto the montmorillonite nanosheets based on cation exchange mechanism and a pH-responsive desorption manner was detected. At simulated gastric condition (pH 1.2), probable interaction of metal ions from the montmorillonite aluminosilicate structure with tetracycline reduced the antimicrobial activity of released tetracycline. However, at simulated intestinal conditions (pH 7.4) where the main antimicrobial activity of the tetracycline should happen, the released tetracycline showed similar antimicrobial activity compared to the original one. Modification of montmorillonite nanosheets enhanced the control of its antimicrobial activity probably due to the changes in the aluminosilicate structure of montmorillonite nanosheets in the modification process. Furthermore, a simulated digestion experiment revealed that the smart control of the antimicrobial activity of the tetracycline using montmorillonite nanosheets was not altered by the harsh conditions of the media. The results of this study would help in the development of advanced nanocarrier for antimicrobial agents which could help problems such as antimicrobial resistance.