Cationic Molecular Umbrellas as Antibacterial Agents with Remarkable Cell-Type Selectivity

Ao Chen, Apostolos Karanastasis, Kaitlyn R. Casey, Matthew Necelis, Benjamin R. Carone, Gregory A. Caputo, Edmund F. Palermo

Research output: Contribution to journalReview articlepeer-review

27 Scopus citations


We synthesized a combinatorial library of dendrons that display a cluster of cationic charges juxtaposed with a hydrophobic alkyl chain, using the so-called "molecular umbrella" design approach. Systematically tuning the generation number and alkyl chain length enabled a detailed study of the structure-activity relationships in terms of both hydrophobic content and number of cationic charges. These discrete, unimolecular compounds display rapid and broad-spectrum bactericidal activity comparable to the activity of antibacterial peptides. Micellization was examined by pyrene emission and dynamic light scattering, which revealed that monomeric, individually solvated dendrons are present in aqueous media. The antibacterial mechanism of action is putatively driven by the membrane-disrupting nature of these cationic surfactants, which we confirmed by enzymatic assays on E. coli cells. The hemolytic activity of these dendritic macromolecules is sensitively dependent on the dendron generation and the alkyl chain length. Via structural optimization of these two key design features, we identified a leading candidate with potent broad-spectrum antibacterial activity (4-8 μg/mL) combined with outstanding hemocompatibility (up to 5000 μg/mL). This selected compound is >1000-fold more active against bacteria as compared to red blood cells, which represents one of the highest selectivity index values ever reported for a membrane-disrupting antibacterial agent. Thus, the leading candidate from this initial library screen holds great potential for future applications as a nontoxic, degradable disinfectant.

Original languageEnglish (US)
Pages (from-to)21270-21282
Number of pages13
JournalACS Applied Materials and Interfaces
Issue number19
StatePublished - May 13 2020

All Science Journal Classification (ASJC) codes

  • Materials Science(all)


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