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Biotechnol Lett (2011) 33:411416 DOI 10.1007/s10529-010-0419-1
ORIGINAL RESEARCH PAPER
On structural damage incurred by bacteria upon exposure to hydrophobic polycationic coatings
Bryan B. Hsu Jie Ouyang Sze Yinn Wong
Paula T. Hammond Alexander M. Klibanov
Received: 10 August 2010 / Accepted: 16 September 2010 / Published online: 30 September 2010 Springer Science+Business Media B.V. 2010
Abstract Hydrophobic polycations previously developed by us efciently kill E. coli and Staphylococcus aureus on contact. As visualized by electron microscopy herein, these pathogenic bacteria incur marked morphological damage from the exposure to these N-alkylated-polyethylenimine paints which results in the leakage of an appreciable fraction of the total cellular protein. The quantity and composition of that leaked protein is similar to that released upon traditional lysozyme/EDTA treatment, thus providing insights into the mechanism of action of our microbicidal coatings.
Keywords Antibacterial Escherichia coli
Polycation Polyethylenimine
Staphylococcus aureus
Introduction
Pathogenic microbes continue to exert their deleterious effects on human health despite numerous antiseptics and antibiotics currently in use. Our strategy of addressing this critical public health problem is to prevent infection by inactivating microbes during transmission. To this end, we have developed hydrophobic polycationic surface treatments with potent, on-contact, broad-spectrum efcacy against pathogenic bacteria, fungi, and viruses (Klibanov 2007).
Further innovation in this area would benet from understanding the mechanism by which our coatings inactivate microbes. We have previously demonstrated that upon exposure to certain N-alkylated-PEIs (PEI = polyethylenimine) both Gram-negative and Gram-positive bacteria are killed because the integrity of their cellular membranes is compromised (Milovic et al. 2005; Park et al. 2006). Herein we report further progress in elucidating how these hydrophobic polycations kill bacteria. In particular, we have determined by scanning electron microscopy that bacteria suffer severe structural damage upon contact with the N,N-Dodecyl,methyl-PEI surface
B. B. Hsu A. M. Klibanov (&)
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA e-mail: [email protected]
A. M. KlibanovDepartment of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
S. Y. Wong P. T. Hammond
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
B. B. Hsu S. Y. Wong P. T. Hammond
A. M. KlibanovInstitute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
J. OuyangCollege of Biological Sciences and Technology, Beijing Forestry...