In situ formation of tetraphenylethylene nano-structures on microgels inside living cells via reduction-responsive self-assembly

Tetraphenylethylene-DNA conjugates: influence of sticky ends and DNA sequence length on the supramolecular assembly of AIE-active vesicles

The supramolecular assembly of DNA conjugates, functionalized with tetraphenylethylene (TPE) sticky ends, into vesicular structures is described. The aggregation-induced emission (AIE) active TPE units allow monitoring the assembly process by fluorescence spectroscopy. The number of TPE modifications in the overhangs of the conjugates influences the supramolecular assembly behavior. A minimum of two TPE residues on each end are required to ensure a well-defined assembly process. The design of the presented DNA-based nanostructures offers tailored functionalization with applications in DNA nanotechnology.

The supramolecular assembly of tetraphenylethylene (TPE)–DNA conjugates is presented. The length of the TPE sticky ends exerts a pronounced effect on the formation of aggregation-induced emission (AIE)-active vesicles.

Antibacterial AIE polycarbonates endowed with selective imaging capabilities by adjusting the electrostaticity of the mixed-charge backbone

Combining rapid microbial discrimination with antibacterial properties, multi-functional biomacromolecules allow the timely diagnosis and effective treatment of infectious diseases. Through a two-step approach involving organocatalytic ring-opening copolymerization and thiol-ene modification, aggregation-induced emission (AIE) polycarbonates decorated with tertiary amines were prepared. After being ionized using acetic acid, the obtained cationic AIE polycarbonate with excellent water solubility showed bacteria imaging capabilities and antibacterial activities toward both Gram-positive S. aureus and Gram-negative E. coli. It was indicated via scanning electron microscope images that the bactericidal mechanism involved membrane lysis, consistent with most cationic polymers. Through further co-grafting carboxyl and tertiary amine groups, mixed-charge AIE polycarbonates were obtained. The isoelectric points of such mixed-charge AIE polycarbonates could be simply tuned based on the grafting ratio of positive and negative moieties. Compared with the cationic AIE polycarbonate, mixed-charge AIE polycarbonates allowed the rapid and selective imaging of S. aureus, but not E. coli. The selectivity probably arose from the lower binding forces between the mixed-charge AIE polycarbonates and the low-negative-charge components of the E. coli surface. Therefore, these biodegradable polycarbonates, which integrated selective bacteria imaging and antibiotic abilities, potentially suggest a precision medicine approach for infectious diseases. The overall synthesis approach and mixed-charge AIE polycarbonates provide new references for the design and application of bio-related AIE polymers.