Intelligent Hybrid Hydrogels for Rapid In Situ Detection and Photothermal Therapy of Bacterial Infection.

Diseases induced by bacterial infections increasingly threaten the health of people all over the world; thus, it is urgent and significant to early diagnose and effectively eliminate infections to save people's lives. To this end, we synthesized an intelligent hydrogel that integrated in situ visualized diagnosis and photothermal therapy of bacterial infections. By simply and subtly incorporating pH-sensitive bromothymol blue (BTB) and near-infrared (NIR)-absorbing conjugated polymer (termed as PTDBD) into thermosensitive chitosan (CS)-based hydrogel, the synthesized BTB/PTDBD/CS hydrogel can diagnose the acidic microenvironment of Staphylococcus aureus (S. aureus) biofilm and infected wounds by showing visualized color change. After rapid diagnosis, the hydrogel can immediately treat the infection site by local hyperthermia under irradiation of NIR laser (808 nm) and even the stubborn biofilm that is difficult to eradicate. Since the dominating antibacterial mechanism is hyperthermia, the hybrid hydrogel shows broad-spectrum antibacterial activity against Gram-positive, Gram-negative, and drug-resistant bacteria. In addition, it has low cytotoxicity to normal cells and no effect on the main organs of mice. It paves a brand new avenue to develop smart and facile diagnosis and a treatment platform for bacterial infections.

Organic Polymer Nanoparticles with Primary Ammonium Salt as Potent Antibacterial Nanomaterials.

Bacterial infections induced by drug-resistant strains have become a global crisis. A membrane-disrupted mechanism is considered as an effective way to kill bacteria with little chance to trigger drug resistance. It is necessary to explore and develop new materials based on the membrane-disrupted mechanism to combat bacterial resistance. Here we report the design of organic nanoparticles based on a polymer (PDCP) as highly effective inhibition and bactericidal reagents. The PDCP is devised to have a hydrophobic skeleton and hydrophilic side chain modified with protonated primary amines, which could self-assemble to form organic nanoparticles (PDCP-NPs). By taking advantage of the large surface to volume ratio of nanoparticles, the synthesized PDCP-NPs have enriched positive charges and multiple membrane-binding sites. Research results display that PDCP-NPs have highly potent antibacterial activity in vitro and vivo, especially for Gram-negative bacteria with low toxicity against mammalian cells. This work design will inspire researchers to develop more membrane-disrupted bactericide and advance the applications of organic nanoparticles in the antibacterial area.

Bactericidal activity-tunable conjugated polymers as a human-friendly bactericide for the treatment of wound infections.

Photodynamic therapy (PDT) has been reported to be an effective alternative to combat bacterial infections even those triggered by drug-resistant strains as there is little chance to develop resistance to this therapy. Therefore, it is imperative to design and synthesize a superior photo-active bactericide for the treatment of bacterial infections. Herein, we synthesized three bactericidal activity-tunable conjugated polymers (P1-P3) with various photoactive capabilities and employed them for the treatment of wound infections with little damage to cells; by altering the construction unit of π-conjugated backbone structures with electron-rich and electron-deficient aromatic heterocycles, the optical properties and ability of reactive oxygen species (ROS) generation could be regulated; this resulted in a tunable killing ability. The cationic quaternary ammonium (QA) groups on the side chains endowed the CPs with not only good dispersibility but also a better interaction with the negatively charged membrane of bacteria. The antibacterial experiments towards ampicillin-resistant Escherichia coli TOP10 (E. coli) and the treatment of wound infections in mice indicate that the P1-P3 have varied bactericidal activities; moreover, P3 has been demonstrated to be a human-friendly bactericide with excellent antibacterial capability. It not only acts as a potential bactericide for the practical treatment of infectious wounds, but also offers guidance for the design and structure control of photo-active bactericides.

[Studies on the effect of Ginkgo biloba extracts on NF-kappaB pathway].

OBJECTIVE: To investigate NF-kappaB and IkappaBalpha activities in HL-60 induced by TNF-alpha in order to understand the molecular mechanism of GbE in asthma treatment. METHODS: The amount of IkappaBalpha in HL-60 cells stimulated by TNF-alpha and GbE was measured by western blotting. Plasmid pNF-kappaB-LuC was transfected and NF-kappaB activity was analyzed by measuring the expression level of luciferase. RESULTS: It showed in the luciferase assay that the activity of NF-kappaB could significantly be suppressed in HL-60 cells after the pretreatment with CGbE. However, the phosphorylation and subsequent degradation of IKBalpha induced by TNF-alpha can not be inhibited in HL-60 cells even we prolonged the treatment time or increased the concentration of GhE. CONCLUSION: GhE can suppress the NF-kappaB gene expression actively on independent of NIK/ IKK/ IkappaBalpha pathway in HL-60 cells.