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Acid-induced and pH-controlled Reversible Switching of Broad-Spectrum Antibacterial Activity



Yin Y. Nelson, Vytautas Reipa, Xiaohong Wang, Kenneth Mineart, Vivek M. Prabhu, Nancy J. Lin, Jirun Sun


Bacterial resistance to antimicrobials is threatening millions of human lives due to indiscriminate overuse and environmental build-up of antibiotics. We present the smart regulation of antibacterial activity in biologically relevant conditions to reduce the amount of antimicrobial needed. Specifically, the antibacterial efficacy is boosted by adding acid and controlled by pH between 4 to 8 through reversible self-assembly of a novel broad-spectrum antibacterial quaternary pyridinium salt (QPS). The design, synthesis and characterization of this QPS compound is discussed. Based on minimum bactericidal concentrations, this QPS is 16- fold more effective on Escherichia coli and 8-fold more effective on Streptococcus mutans at pH 4.1, as compared to pH 7.9. In addition, its physicochemical properties also shift accordingly. The acid-induced, pH-controlled antibacterial activity results from the reversible switching of QPS self-assembly which adjusts the number of free QPS molecules. Such control of antibacterial efficacy may be triggered by metabolic acidic byproducts of bacteria to provide precisely localized treatment for infection; it also has the potential to regulate bacterial growth in response to the metabolic activity of acid-producing bacteria and biofilms.
Journal of the American Chemical Society


smart material, antimicrobial activity, ph-sensitive, quaternary pyridinium salt, self-assembly


Nelson, Y. , Reipa, V. , Wang, X. , Mineart, K. , Prabhu, V. , Lin, N. and Sun, J. (2018), Acid-induced and pH-controlled Reversible Switching of Broad-Spectrum Antibacterial Activity, Journal of the American Chemical Society, [online], (Accessed April 18, 2024)
Created February 13, 2018, Updated February 12, 2020