Bacterial biofilms are inherently resistant to antimicrobial agents and are difficult to eradicate with conventional antimicrobial agents, resulting in many persistent and chronic bacterial infections. In this contribution, a new strategy for reversing the biofilm-associated antibiotic resistance has been explored by induction of a carborane ruthenium(II)-arene complex (FcRuSB). Our results demonstrate that the FcRuSB could be utilized as an inducer to efficiently reverse the biofilm-associated antibiotic resistance of multidrug-resistant (MDR) clinical isolates of Staphylococcus aureus and Pseudomonas aeruginosa. The induced effect of FcRuSB is correlated with a considerable decrease in the expression of extracellular matrix proteins (EMP) of the two strains. The considerable decrease of the EMP of induced cells, resulting in the reduction of adherence and biofilm formation ability of the two types of MDR pathogens, and then can cause significantly enhanced sensitivity of them to antibiotics.
LI ShuiHongWU ChangYuTANG XiaoGAO ShengPingZHAO XinQingYAN HongWANG XueMei
Biocompatible carbon-spheres-based nanocomposites exhibit great potential in biomedical and clinical applications. In this contribution we report the first green photochemical synthesis of carbon spheres through in-situ enwrapping around silver nanoparticles(CS–Ag NPs). Since mesoporous carbon spheres can provide the location for combining Ag NPs and other agents, one-step synthesis of glutathione-stabilized CS–Ag NPs could be readily realized by photoreduction. TEM characterization of CS–Ag NPs nanocomposites illustrates that Ag NPs were superbly wrapped inside the carbon spheres and also adhered to the surfaces of the carbon spheres. These porous CS–Ag NPs show excellent fluorescence and effective antibacterial efficiency, exhibiting ideal lengthened activities against Escherichia coli and Staphylococcus aureus compared with bare Ag NPs. The relevant rationale behind it could be attributed to the fact that CS–Ag NPs nanocomposites can provide some excellent niches for the durable and slow release of silver ions. This raises the possibility of promising applications of CS–Ag NPs nanocomposites as excellent antibacterial agents for the efficient monitoring of some disease-related bacteria.
Wei GeXiaoli LiuJing YeQiwei LiHui JiangXuemei Wang
The interactions between the new organometallic complexes, ferrocene-substituted dithio-o-carborane conjugates (denoted as FcSB1, FcSB2 and FcSBCO) and hemoglobin (Hb) are investigated by electrochemistry, fluorescence and UV-vis absorption spectroscopy. The results demonstrate that FcSB1, FcSB2 and FcSBCO can bind to the heme iron center through the replacement of the weakly bound H2O/O2 in the distal heme pocket of Hb by their sulfur donor atoms, inducing the allosteric change from the R state (oxygenated conformation, relax) to T state (deoxygenated conformation, tense). The binding affinity is in the order of FcSBCO>FcSB2>FcSB1. Moreover, the fluorescence study illustrates that the three ferrocene-carborane conjugates differently affect the quarterly and tertiary structures as well as the polarity in the surrounding of the Trp and Tyr residues in Hb. Typically, FcSB2 mainly induces alterations of the microenvironment around the β37Trp residue which is located on the α1β2 interface of Hb. Such distinct influences are attributed to the structural features of FcSB1, FcSB2 and FcSBCO containing hydrophobic ferrocenyl and carboranyl units as well as C=O group. Screening the protein-binding behavior can signify the potential bioactivity of such molecules and may be helpful in the future development of promising multifunctional metallodrugs.
WU ChunHui1,3, YE HongDe2, JIANG Hui1, WANG XueMei1 & YAN Hong2 1State Key Lab of Bioelectronics (Chien-Shiung Wu Lab), Southeast University, Nanjing 210096, China 2State Key Laboratory of Coordination Chemistry
Recently much attention has been paid to the application of metal hybrid nanoparticles in industrial catalytic fields because of their super-efficient catalytic activity and attractive properties. We explored a novel strategy to prepare GSH-capped Pt–Au–Ag-hybrid nanoclusters through the synergistic effect between ascorbic acid(VC) and glutathione(GSH) with chloroplatinic acid, chloroauric acid, and silver nitrate as precursors. The potential utilization of as-prepared GSH-capped Pt–Au–Aghybrid nanoclusters for catalytic applications has been evaluated through the reduction of 4-nitrophenol(4-NP) with NaBH4; we obtained the kinetic data by monitoring with UV-Vis spectroscopy. Our results illustrate that GSH-capped Pt–Au– Ag-hybrid nanoclusters could facilitate the process of reduction of 4-NP in a way that is unprecedented. This approach may offer a novel, non-cytotoxicity, efficient catalyst for industry.
We report in this study the effects of red-emitting CdTe QDs capped with cysteamine(Cys-CdTe) on the in vitro anticancer activity of the well-known flavenoid quercetin(Qu). Various techniques, including the methylthiazolyldiphenyl-tetrazolium bromide assay, the real-time cell electronic sensing system, the optical and fluorescence imaging, and electrochemical methods have been utilized to study the potential interactions of Cys-CdTe QDs with Qu. The observations demonstrate that the safe-dosage Cys-CdTe QDs can greatly improve the drug uptake and enhance the inhibition efficiency of Qu towards the proliferation of cancer cells such as HepG2 cells. This study implies that Cys-CdTe QDs may be used for cancer therapy and that they exert a synergic anticancer effect when bound to drug molecules.
As one of the active compounds derived from Traditional Chinese Medicine,Celastrol(CSL)had cytotoxicity for human leukemia cancer cells K562 and its multidrug-resistant cell line K562/A02.Here,we introduced cysteamine-modified CdTe QDs as the labeling and drug carrier into CSL research and found that the self-assembly and conjugation of anticancer molecular CSL with the Cys-CdTe QDs could significantly increase the drug’s cytotoxicity for K562 cells.More important,these CSL-Cys-CdTe nanocomposites could overcome the multidrug resistance of K562/A02 cells and efficiently inhibit the cancer cell proliferation by realizing the pH-sensitive responsive release of CSL to cancer cells.The enhanced cytotoxicity was caused by the increase of the G2/M phase arrest for K562/A02 cells as well as for K562 cells.Cys-CdTe QDs can readily bind on the cell plasma membranes and be internalized into cancer cells to trace and detect human leukemia cancer cells in real time.In addition,these Cys-CdTe QDs can facilitate the inhibition of the multidrug resistance of K562/A02 cells and readily induce apoptosis.As a good photosensitizer for the therapy,labeling,and tracing of cancer cells,the combination of CSL with Cys-CdTe QDs can optimize the use of and a new potential therapy method for CSL and yield new tools to explore the mechanisms of active compounds from Traditional Chinese Medicine.
LI JingYuanSHI LiXinSHAO YiXiangSELKE MatthiasCHEN BaoAnJIANG HuiWANG XueMei
