Design, synthesis and evaluation of novel 9-arylalkyl-10-methylacridinium derivatives as highly potent FtsZ-targeting antibacterial agents

With the increasing incidence of antibiotic resistance, new antibacterial agents having novel mechanisms of action hence are in an urgent need to combat infectious diseases caused by multidrug-resistant (MDR) pathogens. Four novel series of substituted 9-arylalkyl-10-methylacridinium derivatives as FtsZ inhibitors were designed, synthesized and evaluated for their antibacterial activities against various Gram-positive and Gram-negative bacteria. The results demonstrated that they exhibited broad-spectrum activities with substantial efficacy against MRSA and VRE, which were superior or comparable to the berberine, sanguinarine, linezolid, ciprofloxacin and vancomycin. In particular, the most promising compound 15f showed rapid bactericidal properties, which avoid the emergence of drug resistance. However, 15f showed no inhibitory effect on Gram-negative bacteria but biofilm formation study gave possible answers. Further target identification and mechanistic studies revealed that 15f functioned as an effective FtsZ inhibitor to alter the dynamics of FtsZ self-polymerization, which resulted in termination of the cell division and caused cell death. Further cytotoxicity and animal studies demonstrated that 15f not only displayed efficacy in a murine model of bacteremia in vivo, but also no significant hemolysis to mammalian cells. Overall, this compound with novel skeleton could serve as an antibacterial lead of FtsZ inhibitor for further evaluation of drug-likeness.

N-Substituted Acridinium as a Multi-Responsive Recognition Unit in Supramolecular Chemistry

The N-substituted acridinium motif is an electron-deficient unit with appealing multi-responsive properties which have been exploited in the field of supramolecular chemistry. This building block reversibly alters its shape, with its chemical and optical properties in response to a chemical or redox signal. In this Review, we discuss selected examples where the switchable properties of 9-aryl-N-methyl-acridinium lead to actuators, multi-input and multi-output systems, host or guest systems, and to interlocked systems with controllable motion.

Surfactant Aggregates Encapsulating and Modulating: An Effective Way to Generate Selective and Discriminative Fluorescent Sensors

The heterogeneous structure and dynamic balancing nature of surfactant aggregates make them attractive in developing fluorescent sensors. They can provide a number of advantages, e.g., enhanced fluorescence stability and quantum yield, detection capability in aqueous solutions, and easy operation. Thus, various strategies have been used to construct surfactant aggregate-based fluorescent sensors. Surfactant aggregates play various roles in different strategies and realize multiple sensing behaviors. Many new functions have been discovered for surfactant aggregates in constructing fluorescent sensors. In this feature article, we briefly summarize the development of surfactant aggregate-based fluorescent sensors and their applications in three different types of sensing: selective sensing, multiple analyte sensing, and cross-reactive sensing. For each type of sensing, the design strategies and the roles of surfactant aggregates are particularly introduced. An understanding of these aspects will help to expand the applications of surfactant assemblies in the sensing field.

Water-soluble β-aminobisulfonate building blocks for pH and Cu2+ indicators

Two phenyl β-aminobisulfonate ligands characterised by UV-visible absorption, EPR and ¹H NMR spectroscopy exhibit evidence for binding with Cu²⁺ in water and methanol.

Water-soluble amino(ethanesulfonate) and [bis(ethanesulfonate)] anthracenes as fluorescent photoinduced electron transfer (PET) pH indicators and Fe3+ chemosensors

Two novel anthracene-based chemosensors appended with amino(ethanesulfonate) groups function as fluorescent PET turn-on probes for protons and turn-off probes for ferric ions in water.