Design, synthesis, and applications of pyrene-quinoline based cell-permeable AIEgen for cellular imaging and antibacterial activity

Abstract

Herein, we describe the design and synthesis of PyQ, a novel pyrene-quinoline based cell-permeable aggregation-induced emission luminogen (AIEgen) with implications in cellular imaging and antibacterial activity. The synthesised compound was characterised by NMR, HR-MS and IR studies. PyQ exhibited AIE in the DMSO-water mixture and this was confirmed by fluorescence spectroscopic studies. The addition of water to the DMSO solution of PyQ resulted in enhanced fluorescence emission for up to 70% water in DMSO. The SEM and TEM data also confirmed the aggregate formation in addition to DLS, quantum yield and lifetime measurements. The synthesised AIE compound was found to be non-toxic and cell-permeable that could readily label the cytoplasm and plasma membrane. Of note, PyQ exhibited both blue and green emission inside the cell. We further evaluated the antibacterial activity of PyQ aggregates against the model Gram-negative bacteria, Escherichia coli (E. coli) using the standard colony forming unit (CFU) counting assay. The results suggest that the aggregates were potent antibacterial agents and the SEM data clearly showed the disruption of the bacterial membrane. Taken together, this work provides a simple and efficient technique for the development of an AIEgen with antibacterial activity as well as rapid cellular imaging with both blue and green emission.