Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 9 de 9
Filter
Add more filters










Database
Language
Publication year range
1.
Chem Commun (Camb) ; 56(92): 14459-14462, 2020 Nov 19.
Article in English | MEDLINE | ID: mdl-33146636

ABSTRACT

Two Pt complexes with high quantum yields and photostability, and low cytotoxicity, were developed to track RNA G-quadruplexes (GQs) in live cells. Higher number and intensity, and longer lifetime of fluorescent foci in cancer cells than those in healthy cells suggest that the quantity and folding dynamics of RNA GQs could not only correlate to their biological functions, but be two novel biomarkers to characterize cancerous cells.


Subject(s)
Biomarkers, Tumor/analysis , Coordination Complexes/chemistry , DNA/chemistry , Fluorescent Dyes/chemistry , Neoplasms/diagnostic imaging , Platinum/chemistry , Animals , Biosensing Techniques , CHO Cells , Cattle , Cricetulus , G-Quadruplexes , HeLa Cells , Humans , Kinetics , Liver/metabolism , Molecular Docking Simulation , Nucleic Acid Conformation , Optical Imaging , RNA/metabolism
2.
Angew Chem Int Ed Engl ; 59(39): 16997-17003, 2020 Sep 21.
Article in English | MEDLINE | ID: mdl-32463536

ABSTRACT

The electrochemical nitrogen reduction reaction (NRR) offers a sustainable solution towards ammonia production but suffers poor reaction performance owing to preferential catalyst-H formation and the consequential hydrogen evolution reaction (HER). Now, the Pt/Au electrocatalyst d-band structure is electronically modified using zeolitic imidazole framework (ZIF) to achieve a Faradaic efficiency (FE) of >44 % with high ammonia yield rate of >161 µg mgcat -1 h-1 under ambient conditions. The strategy lowers electrocatalyst d-band position to weaken H adsorption and concurrently creates electron-deficient sites to kinetically drive NRR by promoting catalyst-N2 interaction. The ZIF coating on the electrocatalyst doubles as a hydrophobic layer to suppress HER, further improving FE by >44-fold compared to without ZIF (ca. 1 %). The Pt/Au-NZIF interaction is key to enable strong N2 adsorption over H atom.

3.
Angew Chem Int Ed Engl ; 56(21): 5904-5908, 2017 05 15.
Article in English | MEDLINE | ID: mdl-28440962

ABSTRACT

The structure and function of naturally occurring proteins are governed by a large number of amino acids (≥100). The design of miniature proteins with desired structures and functions not only substantiates our knowledge about proteins but can also contribute to the development of novel applications. Excellent progress has been made towards the design of helical proteins with diverse functions. However, the development of functional ß-sheet proteins remains challenging. Herein, we describe the construction and characterization of four-stranded ß-sheet miniproteins made up of about 19 amino acids that bind heme inside a hydrophobic binding pocket or "heme cage" by bis-histidine coordination in an aqueous environment. The designed miniproteins bound to heme with high affinity comparable to that of native heme proteins. Atomic-resolution structures confirmed the presence of a four-stranded ß-sheet fold. The heme-protein complexes also exhibited high stability against thermal and chaotrope-induced unfolding.


Subject(s)
Heme/chemistry , Proteins/chemistry , Amino Acid Sequence , Models, Molecular , Protein Binding , Protein Conformation, beta-Strand
4.
Bioconjug Chem ; 28(4): 1059-1067, 2017 04 19.
Article in English | MEDLINE | ID: mdl-28228012

ABSTRACT

In comparison to conventional tumor treatment methods, photothermal therapy (PTT) is one of the innovative therapeutic strategies that employs light to produce localized heat for targeted ablation of cancer cells. Among the various kinds of heat generation nanomaterials, transition metal dichalcogenide nanosheets, especially molybdenum disulfide (MoS2), have recently been investigated as one of the promising PTT candidates because of their strong absorbance in the near-infrared (NIR) tissue transparency window and excellent photothermal conversion capability. In line with the great potential of MoS2-based nanomaterials in biomedical applications, their intrinsic therapeutic performance and corresponding cellular response are required to be continually investigated. In order to further improve MoS2-based PTT efficacy and dissect the molecular mechanism during heat stimuli, in this study, we successfully designed a novel and effective PTT platform by integration of MoS2 nanosheets with peptide-based inhibition molecules to block the function of heat shock proteins (Hsp90), one type of chaperone proteins that play protective roles in living systems against cellular photothermal response. Such a combined nanosystem could effectively induce cell ablation and viability assays indicated approximately 5-fold higher PTT treatment efficacy (8.8% viability) than that of MoS2 itself (48% viability) upon 808 nm light irradiation. Moreover, different from the case based on MoS2 alone that could cause tumor ablation through the process of necrosis, the detailed mechanism analysis revealed that the inhibition of Hsp90 could significantly increase the photothermally mediated apoptosis, hence resulting in remarkable enhancement of photothermal treatment. Such promising studies provide the great opportunity to better understand the cellular basis of light-triggered thermal response. Moreover, they can also facilitate the rational design of new generations of PTT platforms toward future theranostics.


Subject(s)
Disulfides/radiation effects , Hot Temperature , Molybdenum/radiation effects , Nanocomposites/chemistry , Phototherapy/methods , Apoptosis/drug effects , Cell Survival/drug effects , HCT116 Cells , Humans , Light
5.
Chem Commun (Camb) ; 52(25): 4667-70, 2016 Mar 28.
Article in English | MEDLINE | ID: mdl-26953360

ABSTRACT

A novel theranostic divalent vancomycin analog using a planar 1,8-diazapyrene moiety as a rigid scaffold exhibits potent and selective antibacterial activity against Gram (+) bacteria including vancomycin-resistant strains, while having minimal influence on Gram (-) bacteria and mammalian cells. Moreover, this theranostic analog can be also applied for selective two-photon fluorescence imaging of Gram (+) bacteria.


Subject(s)
Glycopeptides/chemistry , Glycopeptides/pharmacology , Gram-Positive Bacteria/drug effects , Vancomycin Resistance/drug effects , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Gram-Positive Bacteria/metabolism , Gram-Positive Bacteria/ultrastructure , Humans , Microbial Sensitivity Tests , Microscopy, Electrochemical, Scanning , Molecular Structure , Optical Imaging
6.
Bioconjug Chem ; 26(5): 955-61, 2015 May 20.
Article in English | MEDLINE | ID: mdl-25938732

ABSTRACT

Current anticancer chemotherapy often suffers from poor tumor selectivity and serious drug resistance. Proper vectors for targeted delivery and controlled drug release play crucial roles in improving the therapeutic selectivity to tumor areas and also overcoming the resistance of cancer cells. In this work, we developed a novel human serum albumin (HSA) protein-based nanocarrier system, which combines the photoactivatable Pt(IV) antitumor prodrug for realizing the controlled release and fluorescent light-up probe for evaluations of drug action and efficacy. The constructed Pt(IV)-probe@HSA platform can be locally activated by light irradiation to release the active Pt species, which results in enhanced cell death at both drug-sensitive A2780 and cisplatin-resistant A2780cis cell lines when compared to the free prodrug molecules. Simultaneously, the cytotoxicity caused by light controlled drug release would further lead to the cellular apoptosis and trigger the activation of caspases 3, one crucial protease enzyme in apoptotic process, which could cleave the recognition peptide moiety (DEVD) with a flanking fluorescent resonance energy transfer (FRET) pair containing near-infrared (NIR) fluorophore Cy5 and quencher Qsy21 on the HSA nanocarrier surface. The turn-on fluorescence in response to caspase-3 could be assessed by fluorescence microscopy and flow cytometry analysis. Our results supported the hypothesis that such a unique design may present a successful platform for multiple roles: (i) a biocompatible protein-based nanocarrier for drug delivery, (ii) the controlled drug release with strengthened therapeutic effects, (iii) real-time monitoring of antitumor drug efficacy at the earlier stage.


Subject(s)
Antineoplastic Agents/chemistry , Drug Carriers/chemistry , Intracellular Space/metabolism , Light , Molecular Imaging , Organoplatinum Compounds/chemistry , Prodrugs/chemistry , Antineoplastic Agents/metabolism , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Apoptosis/radiation effects , Caspase 3/metabolism , Cell Line, Tumor , Drug Liberation , Enzyme Activation/drug effects , Enzyme Activation/radiation effects , Humans , Models, Molecular , Molecular Conformation , Nanostructures/chemistry , Optical Imaging , Organoplatinum Compounds/metabolism , Organoplatinum Compounds/pharmacology , Prodrugs/metabolism , Time Factors
7.
Chem Commun (Camb) ; 50(47): 6200-3, 2014 Jun 14.
Article in English | MEDLINE | ID: mdl-24709863

ABSTRACT

A simple and unique strategy has been successfully designed for sensitive detection and rapid clearance of bacterial lipopolysaccharides (LPS) by integration of core-shell Fe3O4@SiO2 magnetic nanoparticles with a perylene-diimide (PDI) conjugated LPS-recognition peptide.


Subject(s)
Fluorescence , Imides/chemistry , Lipopolysaccharides/chemistry , Magnetite Nanoparticles/chemistry , Peptides/chemistry , Perylene/analogs & derivatives , Animals , Bacteria/chemistry , Cell Line , Mice , Perylene/chemistry
8.
Nat Commun ; 4: 2004, 2013.
Article in English | MEDLINE | ID: mdl-23759833

ABSTRACT

There has been much controversy over the incorporation of organic-ligand-encapsulated plasmonic nanoparticles in the active layer of bulk heterojunction organic solar cells, where both enhancement and detraction in performance have been reported. Here through comprehensive transient optical spectroscopy and electrical characterization, we demonstrate evidence of traps responsible for performance degradation in plasmonic organic solar cells fabricated with oleylamine-capped silver nanoparticles blended in the poly (3-hexylthiophene):[6,6]-phenyl-C 61-butyric acid methyl ester active layer. Despite an initial increase in exciton generation promoted by the presence of silver nanoparticles, transient absorption spectroscopy reveals no increase in the later free polaron population-attributed to fast trapping of polarons by nearby nanoparticles. The increased trap-assisted recombination is also reconfirmed by light intensity-dependent electrical measurements. These new insights into the photophysics and charge dynamics of plasmonic organic solar cells would resolve the existing controversy and provide clear guidelines for device design and fabrication.

9.
Chem Commun (Camb) ; 47(5): 1601-3, 2011 Feb 07.
Article in English | MEDLINE | ID: mdl-21109901

ABSTRACT

A simple and specific divalent vancomycin-porphyrin has been developed. This divalent vancomycin-porphyrin conjugate indicates promising properties in fluorescent imaging and photodynamic inactivation of vancomycin-sensitive and vancomycin-resistant enterococci (VRE) bacterial strains.


Subject(s)
Anti-Bacterial Agents/pharmacology , Light , Photochemotherapy , Streptococcal Infections/drug therapy , Streptococcus/drug effects , Vancomycin Resistance/drug effects , Vancomycin/pharmacology , Fluorescence , Magnetic Resonance Spectroscopy , Microbial Sensitivity Tests , Streptococcal Infections/microbiology , Streptococcal Infections/pathology
SELECTION OF CITATIONS
SEARCH DETAIL
...