Fig. 1: N-heterocyclic carbene (NHC) formation of oligoimidazolium (OIM) carbon acid and its contribution to bacterial membrane translocation.

A OIMs with free C2-hydrogens are carbon acids that deprotonate in neutral water to form NHCs (II) that are uncharged and hydrophobic. B Non-classical mechanism of translocation: (i) Right side: OIM carbon acid converts to an amphiphilic copolymer (made of hydrophilic cation and hydrophobic NHC repeats) to efficiently translocate across the plasma membrane into bacterial cytosol at lower polymer threshold concentration, as compared with (ii) Left side: a classical cationic polymer that forms physical pores. The OIMs bind with their intracellular target (DNA as previously studied) in bacterial cytosol, resulting in bacterial death (represented in purple), as opposed to classical cationic polymer, which is ineffective in killing the bacterium (live bacterium is represented in brown). Created in BioRender. Chan, M. (2025) https://BioRender.com/zhts02o.