A Dual-Channel Fluorescent Probe for Accurate Diagnosis and Precise Photodynamic Killing of Bacterial Infections by Employing Dual-Mechanism Responses

Bacterial infections pose a huge challenge to global public health, exacerbated by the growing threat of antibiotic resistance due to overuse of antibiotics, and there is an urgent need to develop epidemiological control methods that enable accurate detection and precise treatment. In this study, we present an innovative dual-response integrated probe, Nap-CefTTPy, which is capable of dual-channel fluorescence imaging, synergizing with photodynamic therapy for the accurate diagnosis and precise treatment of bacterial infections. The probe has excellent selectivity for bacteria and can produce two independent spectral responses to bacteria through two different response mechanisms under a single laser excitation, achieving accurate diagnosis of dual-channel bacterial infections. At the same time, it can also produce reactive oxygen species for synergistic photodynamic therapy, which ensures the accuracy of diagnosis and treatment. In a mouse bacterial infection model, it largely promoted the wound healing of S. aureus-infected mice. This platform represents a significant advancement in the field, providing a novel approach for the dual-code mutual correction diagnosis and photodynamic therapy of bacterial infections.

Fluorogenic Probes/Inhibitors of β-Lactamase and their Applications in Drug-Resistant Bacteria

β-Lactam antibiotics are generally perceived as one of the greatest inventions of the 20^th century, and these small molecular compounds have saved millions of lives. However, upon clinical application of antibiotics, the β-lactamase secreted by pathogenic bacteria can lead to the gradual development of drug resistance. β-Lactamase is a hydrolase that can efficiently hydrolyze and destroy β-lactam antibiotics. It develops and spreads rapidly in pathogens, and the drug-resistant bacteria pose a severe threat to human health and development. As a result, detecting and inhibiting the activities of β-lactamase are of great value for the rational use of antibiotics and the treatment of infectious diseases. At present, many specific detection methods and inhibitors of β-lactamase have been developed and applied in clinical practice. In this Minireview, we describe the resistance mechanism of bacteria producing β-lactamase and further summarize the fluorogenic probes, inhibitors of β-lactamase, and their applications in the treatment of infectious diseases. It may be valuable to design fluorogenic probes with improved selectivity, sensitivity, and effectiveness to further identify the inhibitors for β-lactamases and eventually overcome bacterial resistance.

Target-based whole-cell screening by ¹H NMR spectroscopy

An NMR-based approach marries the two traditional screening technologies (phenotypic and target-based screening) to find compounds inhibiting a specific enzymatic reaction in bacterial cells. Building on a previous study in which it was demonstrated that hydrolytic decomposition of meropenem in living Escherichia coli cells carrying New Delhi metallo-β-lactamase subclass 1 (NDM-1) can be monitored in real time by NMR spectroscopy, we designed a cell-based NMR screening platform. A strong NDM-1 inhibitor was identified with cellular IC50 of 0.51 μM, which is over 300-fold more potent than captopril, a known NDM-1 inhibitor. This new screening approach has great potential to be applied to targets in other cell types, such as mammalian cells, and to targets that are only stable or functionally competent in the cellular environment.

Mechanochromic behavior of aryl-substituted buta-1,3-diene derivatives with aggregation enhanced emission

Three tetra-aryl substituted 1,3-butadiene derivatives with aggregation enhanced emission (AEE) and mechanochromic fluorescence behavior have been rationally designed and synthesized. The results suggest an effective design strategy for developing diverse materials with aggregation induced emission (AIE) and significant mechanochromic performance by employing D-π-A structures with large dipole moments.