Phospholipid-Mimetic Aggregation-Induced Emission Luminogens for Specific Elimination of Gram-Positive and Gram-Negative Bacteria

Precise elimination of both Gram-positive and Gram-negative bacteria greatly contributes to the fight against bacterial infection but remains challenging. Herein, we present a series of phospholipid-mimetic aggregation induced emission luminogens (AIEgens) that selectively kill bacteria by capitalizing on both the different structure of two bacterial membrane and the regulated length of substituted alkyl chains of AIEgens. Because of the positive charges that they contain, these AIEgens are able to kill bacteria by anchoring onto the bacterial membrane. For AIEgens with short alkyl chains, they could combine with the membrane of Gram-positive bacteria other than Gram-negative bacteria, because of their complicated outer layers, thus exhibiting selective ablation to Gram-positive bacteria. On the other hand, AIEgens with long alkyl chains have strong hydrophobicity with bacterial membranes, as well as large sizes. This inhibits the combination with Gram-positive bacterial membrane but destroys the membranes of Gram-negative bacteria, resulting in selective ablation to Gram-negative bacteria. Moreover, the combined processes to two bacteria are clearly observed by fluorescent imaging, and in vitro and in vivo experiments show the extraordinary antibacterial selectivity toward a Gram-positive and Gram-negative bacterium. This work could facilitate the development of species-specific antibacterial agents.

Automated summary

In this study, phospholipid-mimetic aggregation induced emission luminogens (AIEgens) were developed to selectively eliminate both Gram-positive and Gram-negative bacteria. By utilizing the different structure of two bacterial membranes and the regulated length of substituted alkyl chains of AIEgens, these AIEgens can anchor onto the bacterial membrane and kill bacteria. AIEgens with short alkyl chains exhibit selective ablation to Gram-positive bacteria, while AIEgens with long alkyl chains selectively destroy the membranes of Gram-negative bacteria. Fluorescent imaging and in vitro/in vivo experiments confirm the extraordinary antibacterial selectivity of these AIEgens towards both types of bacteria. This research could contribute to the development of species-specific antibacterial agents.