Bacterial infection has always been a great threat to public health, and new antimicrobials to combat it are urgently needed. Here, a series of quaternized β-chitin derivatives is prepared simply and homogeneously in an aqueous KOH/urea solution, which is a high-efficiency, energy-saving, and "green" route for the modification of chitin. The mild reaction conditions keep the acetamido groups of β-chitin intact and introduce quaternary ammonium groups on the primary hydroxyl at the C-6 position of the chitin backbone, allowing the quaternized β-chitin derivatives (QCs) to easily form micelles. These QCs are found to exhibit excellent antimicrobial activities against Escherichia coli, Staphylococcus aureus, Candida albicans, and Rhizopus oryzae with minimum inhibitory concentrations (MICs) of 8, 12, 60, and 40 µg mL , respectively. As a specific highlight, their inherent outstanding biocompatibility and significant accelerating effects on the healing of uninfected, E. coli-infected, and S. aureus-infected wounds imply that these novel polysaccharide-based materials can be used as dressings for clinical skin regeneration, particularly for infected wounds.

A novel silver-mediated highly selective oxidative C-H/C-H functionalization of 1,3-dicarbonyl compounds with terminal alkynes for the creation of polysubstituted furans and pyrroles in one step has been demonstrated. Promoted by the crucial silver species, perfect selectivity and good to excellent yields could be achieved. This protocol represents an extremely simple and atom-economic way to construct polysubstituted furans and pyrroles from basic starting materials under mild conditions.

A novel silver-mediated highly selective C-H/N-H oxidative cross-coupling/cyclization between 2-aminopyridines and terminal alkynes has been demonstrated. This approach provided a simple way to construct heteroaromatic imidazo[1,2-a]pyridines. By using this protocol, the marketed drug zolimidine (antiulcer) could be synthesized easily.

Biofilms are defined as aggregation of single cell microorganisms and associated with over 80% of all the microbial infections. Pseudomonas aeruginosa is a Gram‐negative opportunistic pathogen capable of leading to various infections in immunocompromised people. Recent studies showed that norspermidine, a kind of polyamine, prevented and disrupted biofilm formation by some Gram‐negative bacterium. In this study, the effects of norspermidine on P. aeruginosa biofilm formation and eradication were tested. Microtiter plate combined with crystal violet staining was used to study the effects of norspermidine on P. aeruginosa initial attachment, then we employed SEM (scanning electron microscope), qRT‐PCR, and QS‐related virulence factor assays to investigate how norspermidine prevent biofilm formation by P. aeruginosa. We reported that high‐dose norspermidine had bactericide effect on P. aeruginosa, and norspermidine began to inhibit biofilm formation and eradicate 24‐h mature biofilm at concentration of 0.1 and 1 mmol/L, respectively, probably by preventing cell‐surface attachment, inhibiting swimming motility, and downregulating QS‐related genes expression. To investigate the potential utility of norspermidine in preventing device‐related infections, we found that catheters immersed with norspermidine were effective in eradicating mature biofilm. These results suggest that norspermidine could be a potent antibiofilm agent for formulating strategies against P. aeruginosa biofilm.

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Dynamic chemistry has been recently applied to design injectable hydrogels capable of self-healing. Among current strategies for preparing hydrogels that are suitable for cell encapsulation and culture, the fabrication of injectable, self-healing hydrogels is immensely superior. Here, novel β-chitin-based, injectable, self-healing hydrogels were constructed through the self-assembly and entanglement of amphiphilic quaternized βchitin (QC) and hydrophilic oxidized dextran (OD) chains as well as the dynamic Schiff base linkages without extra additives under physiological conditions. The gelation time, viscoelastic behavior, mechanical properties, biodegradability, stimulus sensitivity, shear-thinning ability and self-healing properties of the QC/OD hydrogels were thoroughly characterized. Moreover, the QC/OD hydrogels could be applied for the controlled pHsensitive release of doxorubicin hydrochloride. Because of the excellent cytocompatibility, the QC/OD hydrogels were further used as a promising platform for the three-dimensional encapsulation and culture of NIH-3T3 cells and mouse bone marrow-derived mesenchymal stem cells. Specifically, these novel β-chitin-based hydrogels can be used as an antibacterial vehicle for the delivery of cells in the gel form and thus have potential for applications in regenerative medicine, drug/gene/cell delivery, and cell therapy.

Burkholderia thailandensis infection in humans is uncommon. We describe a case of B. thailandensis infection in a person in China, a location heretofore unknown for B. thailandensis. We identified the specific virulence factors of B. thailandensis, which may indicate a transition to a new virulent form.

Background: Increasing bacterial infections as well as a rise in bacterial resistance call for the development of novel and safe antimicrobial agents without inducing bacterial resistance. Nanoparticles (NPs) present some advantages in treating bacterial infections and provide an alternative strategy to discover new antibiotics. Here, we report the development of novel self-assembled fluorescent organic nanoparticles (FONs) with excellent antibacterial efficacy and good biocompatibility.Methods: Self-assembly of 1-(12-(pyridin-1-ium-1-yl)dodecyl)-4-(1,4,5-triphenyl-1H-imidazol-2-yl)pyridin-1-ium (TPIP) in aqueous solution was investigated using dynamic light scattering (DLS) and transmission electron microscopy (TEM). The bacteria were imaged under a laser scanning confocal microscope. We evaluated the antibacterial efficacy of TPIP-FONs in vitro using sugar plate test. The antimicrobial mechanism was explored by SEM. The biocompatibility of the nanoparticles was examined using cytotoxicity test, hemolysis assay, and histological staining. We further tested the antibacterial efficacy of TPIP-FONs in vivo using the S. aureus-infected rats.Results: In aqueous solution, TPIP could self-assemble into nanoparticles (TPIP-FONs) with characteristic aggregation-induced emission (AIE). TPIP-FONs could simultaneously image gram-positive bacteria without the washing process. In vitro antimicrobial activity suggested that TPIP-FONs had excellent antibacterial activity against S. aureus (MIC = 2.0 µg mL-1). Furthermore, TPIP-FONs exhibited intrinsic biocompatibility with mammalian cells, in particular, red blood cells. In vivo studies further demonstrated that TPIP-FONs had excellent antibacterial efficacy and significantly reduced bacterial load in the infectious sites.Conclusion: The integrated design of bacterial imaging and antibacterial functions in the self-assembled small molecules provides a promising strategy for the development of novel antimicrobial nanomaterials.