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1.
J Stroke Cerebrovasc Dis ; 33(7): 107736, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38679216

RESUMO

BACKGROUND: Ischemic stroke remains the predominant contributor to mortality and disability globally. Microglia undergo rapid activation and initiate inflammatory cascade reactions by phenotypic polarization, participating in the regulation of inflammatory injury and tissue repair post-ischemic stroke. Regulating microglia-mediated neuroinflammation is a promising therapeutic strategy for ischemic stroke. Previously, we designed and synthesized a novel p55PIK inhibitor, TAT-N15 polypeptide, which presents inhibitive activity on NF-κB signaling-mediated inflammation in acute conjunctivitis and allergic rhinitis. The present study aimed to explore the therapeutic effect and mechanism of TAT-N15 on ischemia stroke. METHODS: The mouse model of transient cerebral ischemia was made using the intraluminal filament method. After being treated with daily intraperitoneal injections of TAT-N15 (10 mg/kg) for 7 d, the neurological outcomes and the cerebral infarction volume were evaluated. Histopathology of the ischemia cerebral hemisphere was observed by H&E and Nissl staining. Neuronal survival, astrogliosis, and co-labeling of CD86/Iba1 and CD206/Iba1 were detected by immunofluorescence. The cell apoptosis was estimated by TUNEL staining. The expression levels of apoptosis-associated proteins, proinflammatory cytokines, protein markers of M1 and M2 microglia, and the phosphorylation of NF-κB and STAT3 proteins in the ischemic penumbra were detected by Western blot. RESULTS: TAT-N15 treatment significantly decreased the infarct volume and alleviated neurological functional impairment, neuronal injury, and neuron apoptosis. Meanwhile, TAT-N15 treatment restrained the activation of microglia and astrocytes as well as the protein expression of proinflammatory cytokine in ischemic penumbra. Additionally, the administration of TAT-N15 treatment resulted in a significant reduction in the density of M1 phenotype microglia while concurrently increasing the density of M2 phenotype microglia within the ischemic penumbra. Finally, mechanical analysis unveiled that TAT-N15 exerted a substantial inhibitory effect on the protein expression of phosphorylated STAT3 and NF-κB. CONCLUSION: TAT-N15 may inhibit neuroinflammation via regulating microglia activation and polarization through the STAT3/NF-κB pathway, which exhibits the neuroprotection effect in ischemic stroke.

2.
Chem Sci ; 14(21): 5665-5671, 2023 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-37265737

RESUMO

The direct catalytic α-hydrocarbylation of readily available amino acids with halohydrocarbons is one of the most straightforward methods leading to α,α-disubstituted non-proteinogenic α-amino acid compounds. However, all the reported methodologies depend on N-protected amino acids as starting materials. Herein, we report on three highly efficient aldehyde-catalyzed direct α-hydrocarbylations of N-unprotected amino acid esters with aryl-, allyl-, and benzyl halides. By promoting a simple chiral BINOL-aldehyde catalyst or combining catalysts of a chiral aldehyde and Lewis acid ZnCl2, the asymmetric α-arylation, α-allylation, and α-benzylation of amino acid esters with the corresponding halohydrocarbons proceed smoothly, producing α,α-disubstituted α-amino acids in moderate-to-high yields and good-to-excellent enantioselectivities. The asymmetric α-arylation reaction can be applied in the formal synthesis of the clinical candidate compound (+)-AG-041R. Based on the results given by control experiments, three reaction models are proposed to illustrate the stereoselective-control outcomes.

3.
Nat Commun ; 13(1): 7290, 2022 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-36435942

RESUMO

The combined catalytic systems derived from organocatalysts and transition metals exhibit powerful activation and stereoselective-control abilities in asymmetric catalysis. This work describes a highly efficient chiral aldehyde-nickel dual catalytic system and its application for the direct asymmetric α-propargylation reaction of amino acid esters with propargylic alcohol derivatives. Various structural diversity α,α-disubstituted non-proteinogenic α-amino acid esters are produced in good-to-excellent yields and enantioselectivities. Furthermore, a stereodivergent synthesis of natural product NP25302 is achieved, and a reasonable reaction mechanism is proposed to illustrate the observed stereoselectivity based on the results of control experiments, nonlinear effect investigation, and HRMS detection.


Assuntos
Aldeídos , Aminoácidos , Aldeídos/química , Aminoácidos/química , Níquel , Estereoisomerismo , Catálise , Ésteres
4.
Chem Sci ; 13(13): 3796-3802, 2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35432891

RESUMO

Chiral α-amino ketones are common structural motifs in natural products and pharmaceuticals, as well as important synthons in organic synthesis. Thus, establishing efficient methods for preparing compounds with these privileged scaffolds is an important endeavor in synthetic chemistry. Herein we disclose a new catalytic asymmetric approach for the synthesis of chiral α-amino ketones through a chiral palladium-catalyzed arylation reaction of in situ generated challenging α-keto imines from previously unreported C-acyl N-sulfonyl-N,O-aminals, with arylboronic acids. The current reaction offers a straightforward approach to the asymmetric synthesis of acyclic α-amino ketones in a practical and highly stereocontrolled manner. Meanwhile, the multiple roles of the chiral Pd(ii) complex catalyst in the reaction were also reported.

5.
Onco Targets Ther ; 13: 5177-5190, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606738

RESUMO

PURPOSE: Phosphatidylinositol 3-kinase (PI3K) plays an important role in tumorigenesis by cross-talking with several signaling pathways. p55PIK is a unique regulatory subunit of PI3K and contains an extra 24-residue N-terminal domain (N24). This study aimed to explore the interaction of p55PIK with p53 and the role of p55PIK in regulating p53-dependent apoptosis in cancer cells. MATERIALS AND METHODS: The expression of p55PIK was detected in cancer cells, and the interaction of p55PIK with p53 was examined by immunoprecipitation and pull-down assay. The expression of p53-dependent apoptosis-related genes was detected by PCR. RESULTS: N24 domain of p55PIK interacted with DNA-specific binding domain (DBD) of p53. The increase or decrease of p55PIK expression led to the change of the expression of p53 and p53-regulated genes in cancer cells. Moreover, N24 peptide led to the change of the expression of p53-regulated genes. Moreover, a membrane-permeable N24 peptide enhanced p53-dependent apoptosis induced by methyl methanesulfonate. CONCLUSION: Our results reveal a novel mechanism that regulates p53-dependent apoptosis in cancer cells via p55PIK-p53 interaction.

6.
ACS Appl Bio Mater ; 3(4): 2132-2139, 2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-35025265

RESUMO

Insulin injection causes great pain to the patient, and nasal mucosal administration of insulin is a novel route for the treatment of diabetes. This strategy could protect insulin from either extensive first-pass metabolism or enzyme degradation in the gastrointestinal tract. With the dynamic boronate esters reversibly formed by phenylboronic acid and diols on nasal mucosal epithelial cell surfaces, we herein developed phenylboronic-acid-functionalized dextran nanoplatforms to enhance the permeability of cargos and boost penetration. The nanoplatforms with excellent loading capacity exhibited significant endocytosis compared with naked insulin. The mechanism of endocytosis was involved in clathrin- and lipid raft/caveolae-dependent endocytic pathways. The in vivo nasal delivery of insulin suggested that these nanoplatforms did not trigger nasal epithelial inflammation and greatly decreased blood sugar levels and improved insulin bioavailability. Collectively, this proof-of-concept study demonstrates a novel carrier of phenylboronic-acid-decorated polymer for insulin delivery and provides a promising approach for the development of a diabetes therapeutic strategy.

7.
Chem Sci ; 10(34): 7878-7886, 2019 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-31588333

RESUMO

Nanoparticles that respond to specific endogenous or exogenous stimuli in tumor tissues are actively being developed to address multidrug resistance owing to multiple advantages, including a prolonged circulation time, enhanced permeability and retention effect, and superior cellular uptake. Although some exciting results have been obtained, existing nanoparticles have limited routes to overcome the drug resistance of tumor cells; this limitation results in a failure to ablate resistant tumors via intravenous administration. To resolve this dilemma, we developed a smart theranostic nanoplatform with programmable particle size, activatable target ligands and in vivo multimodal imaging. This nanoplatform, which includes stealth zwitterionic coating, was shown to be quickly trapped in tumor tissue from the blood circulation within 5 min. Subsequently, the targeting moieties were activated in response to the acidic tumor microenvironment by triggering the zwitterionic shell detachment, driving the peeled nanoparticles to penetrate into tumor cells. These smart nanoparticles completely inhibited drug-resistant tumor growth and did not cause any damage to normal organ tissues in live animals. The designed nanoplatforms simultaneously acted as a nanoprobe for fluorescence imaging. Moreover, we also used noninvasive pharmacokinetic diffuse fluorescence tomography (DFT) to dynamically monitor and in situ real-time trace the nanoplatforms' behavior throughout the entire tumor in live animals. The nanoplatforms enabled rapid drug accumulation and deep penetration throughout the entire tumor. The rate of drug accumulation after the administration of nanoplatforms was five-fold higher compared with that after the administration of the free drug, which resulted in increased drug delivery efficiency and improved antitumor efficacy. Collectively, this hierarchical vehicle design provides promising insights for the development of theragnosis for multidrug resistant tumors.

8.
Adv Mater ; 31(7): e1806024, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30589118

RESUMO

The chronic infections by pathogenic Pseudomonas aeruginosa (P. aeruginosa) remain to be properly addressed. In particular, for drug-resistant strains, limited medication is available. An in vivo pneumonia model induced by a clinically isolated aminoglycoside resistant strain of P. aeruginosa is developed. Tobramycin clinically treating P. aeruginosa infections is found to be ineffective to inhibit or eliminate this drug-resistant strain. Here, a newly developed non-antibiotics based nanoformulation plus near-infrared (NIR) photothermal treatment shows a remarkable antibacterial efficacy in treating this drug-resistant pneumonia. The novel formulation contains 50-100 nm long nanorods decorated with two types of glycomimetic polymers to specifically block bacterial LecA and LecB lectins, respectively, which are essential for bacterial biofilm development. Such a 3D display of heteromultivalent glycomimetics on a large scale is inspired by the natural strengthening mechanism for the carbohydrate-lectin interaction that occurs when bacteria initially infects the host. This novel formulation shows the most efficient bacteria inhabitation and killing against P. aeruginosa infection, through lectin blocking and the near-infrared-light-induced photothermal effect of gold nanorods, respectively. Collectively, the novel biomimetic design combined with the photothermal killing capability is expected to be an alternative treatment strategy against the ever-threatening drug-resistant infectious diseases when known antibiotics have failed.


Assuntos
Materiais Biomiméticos , Hipertermia Induzida/métodos , Fototerapia/métodos , Infecções por Pseudomonas/terapia , Pseudomonas aeruginosa , Células A549 , Abscesso/tratamento farmacológico , Abscesso/patologia , Adesinas Bacterianas/metabolismo , Animais , Biofilmes , Farmacorresistência Bacteriana , Escherichia coli , Compostos de Ouro , Humanos , Lactose/análogos & derivados , Lectinas/antagonistas & inibidores , Lectinas/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Células NIH 3T3 , Nanotubos , Pneumonia Bacteriana/patologia , Pneumonia Bacteriana/terapia , Ácidos Polimetacrílicos , Infecções por Pseudomonas/patologia , Pseudomonas aeruginosa/metabolismo
9.
ACS Appl Bio Mater ; 2(4): 1614-1622, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35026895

RESUMO

The Gram-negative bacteria Pseudomonas aeruginosa is one famous bacterial strain owing to its ability to effectively form biofilms, which is a front-line mechanism of bacterial tolerance. Herein, the near-infrared-induced nanocomposites were one-step prepared by modifying copper sulfide nanoparticle with peptide to effectively eradicate Pseudomonas aeruginosa biofilm through electrostatic interaction, photodynamic effect and photothermal effect. These nanocomposites could rapidly adhere to the surface of bacteria, and irreversible damage the bacterial membrane under near-infrared laser irradiation. Furthermore, the nanocomposites could selectively eliminate bacteria over mammalian cell without distinct toxicity to NIH 3T3 cells. The nanocomposites will exert a far-reaching impact on the future design of biocompatible near-infrared-induced antibacterial agents, exhibiting its potential applications in Gram-negative bacteria and biofilm infections.

10.
Chem Commun (Camb) ; 54(90): 12754-12757, 2018 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-30361728

RESUMO

An entirely new strategy is explored for directional transport delivery of antibiotics to bacteria utilizing a bacteria-activated nanoplatform. The nanoplatform can effectively prevent the premature leakage of the therapeutic payload, but release was triggered when the nanoplatforms adhere to bacteria, promising potential applications for the delivery of a wide-range of antimicrobials.


Assuntos
Antibacterianos/farmacologia , Bacillus amyloliquefaciens/efeitos dos fármacos , Sistemas de Liberação de Medicamentos , Nanopartículas/química , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/química , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Tamanho da Partícula , Propriedades de Superfície
11.
Nanoscale ; 10(39): 18520-18530, 2018 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-30211421

RESUMO

The chronic infection of humans by antibiotic-resistant bacteria and their related biofilm have, so far, not been properly addressed. In the present work, we developed a novel antibacterial nanoplatform showing the most efficient antibiotic-resistant bacteria inhibition and biofilm eradication. This particular formulation contains tobramycin-conjugated graphene oxide, for efficiently capturing bacteria through electrostatic interactions and eliminating bacteria as a "nano-knife", and copper sulphide nanoparticles for enhancing the photothermal and photodynamic properties. This novel formulation can selectively eliminate bacteria over NIH 3T3 cells, and the biofilm eradication capacity was up to 70%. Importantly, the nanoplatforms can inhibit bacterial growth and promote the repair of antibiotic-resistant bacteria-infected wounds on rats without non-specific damage to normal tissue. This work provides an effective, simple, and rapid method for the design and fabrication of near-infrared light-induced nanoplatforms that offer possibilities to treat biofilm-related infections.


Assuntos
Biofilmes/efeitos dos fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Grafite , Nanoestruturas/química , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimento , Tobramicina , Animais , Grafite/química , Grafite/farmacologia , Humanos , Camundongos , Células NIH 3T3 , Tobramicina/química , Tobramicina/farmacologia
12.
Bioconjug Chem ; 29(9): 3222-3230, 2018 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-30152991

RESUMO

Due to the rapid development of bacterial resistance, there is an urgent need to explore new antibacterial agents to substitute for traditional antibiotic therapy. Photodynamic therapy has been identified as a promising bactericidal method to conquer antibiotic-resistant pathogens. To solve the problem of photosensitizer damage to normal tissues in vivo, we developed a boron-dipyrrolemethene (BODIPY)-based glycosylated photosensitizer for ablating Pseudomonas aeruginosa ( P. aeruginosa). This glycosylated photosensitizer exhibited good water solubility and generated 1O2 rapidly in an aqueous solution under light exposure. The photosensitizer did not cause detectable toxicity to human cells in the dark. Importantly, the photosensitizer was able to selectively attach to P. aeruginosa over normal cells, thus resulting in effective pathogen ablation by reactive oxygen species. Moreover, the photosensitizer inhibited over 90% of the biofilm formation produced by P. aeruginosa. The results indicate that the design of the macromolecular photosensitizer-induced bacterial death and inhibited biofilm formation provide a novel strategy for overcoming bacterial infection.


Assuntos
Antibacterianos/farmacologia , Galactose/química , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Antibacterianos/química , Biofilmes/efeitos dos fármacos , Farmacorresistência Bacteriana , Glicosilação , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/toxicidade , Pseudomonas aeruginosa/fisiologia , Pseudomonas aeruginosa/ultraestrutura , Solubilidade , Água
13.
PeerJ ; 6: e4571, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29666752

RESUMO

Complex diseases such as cancer are usually the result of a combination of environmental factors and one or several biological pathways consisting of sets of genes. Each biological pathway exerts its function by delivering signaling through the gene network. Theoretically, a pathway is supposed to have a robust topological structure under normal physiological conditions. However, the pathway's topological structure could be altered under some pathological condition. It is well known that a normal biological network includes a small number of well-connected hub nodes and a large number of nodes that are non-hubs. In addition, it is reported that the loss of connectivity is a common topological trait of cancer networks, which is an assumption of our method. Hence, from normal to cancer, the process of the network losing connectivity might be the process of disrupting the structure of the network, namely, the number of hub genes might be altered in cancer compared to that in normal or the distribution of topological ranks of genes might be altered. Based on this, we propose a new PageRank-based method called Pathways of Topological Rank Analysis (PoTRA) to detect pathways involved in cancer. We use PageRank to measure the relative topological ranks of genes in each biological pathway, then select hub genes for each pathway, and use Fisher's exact test to test if the number of hub genes in each pathway is altered from normal to cancer. Alternatively, if the distribution of topological ranks of gene in a pathway is altered between normal and cancer, this pathway might also be involved in cancer. Hence, we use the Kolmogorov-Smirnov test to detect pathways that have an altered distribution of topological ranks of genes between two phenotypes. We apply PoTRA to study hepatocellular carcinoma (HCC) and several subtypes of HCC. Very interestingly, we discover that all significant pathways in HCC are cancer-associated generally, while several significant pathways in subtypes of HCC are HCC subtype-associated specifically. In conclusion, PoTRA is a new approach to explore and discover pathways involved in cancer. PoTRA can be used as a complement to other existing methods to broaden our understanding of the biological mechanisms behind cancer at the system-level.

14.
ACS Appl Mater Interfaces ; 10(17): 14426-14437, 2018 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-29651836

RESUMO

Biofilm is closely related to chronic infections and is difficult to eradicate. Development of effective therapy strategies to control biofilm infection is still challenging. Aiming at biofilm architecture, we designed and prepared near-infrared-activated thermosensitive liposomes with photothermal and antibiotic synergistic therapy capacity to eliminate Pseudomonas aeruginosa biofilm. The liposomes with positive charge and small size aided to enter the biofilm microchannels and locally released antibiotics in infection site. The liposomes could remain stable at 37 °C and release about 80% antibiotics over 45 °C. The biofilm dispersion rate was up to 80%, which was a 7- to 8-fold rise compared to excess antibiotic alone, indicating that the localized antibiotic release and photothermal co-therapy improved the antimicrobial efficiency. In vivo drug-loaded liposomes in treating P. aeruginosa-induced abscess exhibited an outstanding therapeutic effect. Furthermore, photothermal treatment could stimulate the expression of bcl2-associated athanogene 3 to prevent normal tissue from thermal damage. The near-infrared-activated nanoparticle carriers had the tremendous therapeutic potential to dramatically enhance the efficacy of antibiotics through thermos-triggered drug release and photothermal therapy.


Assuntos
Biofilmes , Antibacterianos , Raios Infravermelhos , Lipossomos , Pseudomonas aeruginosa
15.
J Biomed Inform ; 81: 31-40, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29578099

RESUMO

MicroRNAs (miRNAs) are small, non-coding RNAs involved in the regulation of gene expression at a post-transcriptional level. Recent studies have shown miRNAs as key regulators of a variety of biological processes, such as proliferation, differentiation, apoptosis, metabolism, etc. Aberrantly expressed miRNAs influence individual gene expression level, but rewired miRNA-mRNA connections can influence the activity of biological pathways. Here, we define rewired miRNA-mRNA connections as the differential (rewiring) effects on the activity of biological pathways between hepatocellular carcinoma (HCC) and normal phenotypes. Our work presented here uses a PageRank-based approach to measure the degree of miRNA-mediated dysregulation of biological pathways between HCC and normal samples based on rewired miRNA-mRNA connections. In our study, we regard the degree of miRNA-mediated dysregulation of biological pathways as disease risk of biological pathways. Therefore, we propose a new method, miR2Pathway, to measure and rank the degree of miRNA-mediated dysregulation of biological pathways by measuring the total differential influence of miRNAs on the activity of pathways between HCC and normal states. miR2Pathway proposed here systematically shows the first evidence for a mechanism of biological pathways being dysregulated by rewired miRNA-mRNA connections, and provides new insight into exploring mechanisms behind HCC. Thus, miR2Pathway is a novel method to identify and rank miRNA-dysregulated pathways in HCC.


Assuntos
Carcinoma Hepatocelular/genética , Perfilação da Expressão Gênica , Neoplasias Hepáticas/genética , Informática Médica/métodos , MicroRNAs/metabolismo , Algoritmos , Ritmo Circadiano , Biologia Computacional , Predisposição Genética para Doença , Humanos , Neoplasias/metabolismo , Risco , Transdução de Sinais , Software
16.
Biomacromolecules ; 19(1): 141-149, 2018 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-29141147

RESUMO

A multitude of serious chronic infections are involved in bacterial biofilms that are difficult to eradicate. Here, a water-soluble galactose-functionalized cationic 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based photodynamic therapy agent was synthesized for selectively eliminating the bacterial biofilm. These conjugates can capture bacteria to form aggregations through electrostatic interaction and then generate a large number of reactive oxygen species (ROS) under visible light irradiation to kill the bacteria without the emergence of bacterial resistance. Simultaneously, this agent could effectively inhibit and eradicate both Gram-positive and Gram-negative bacterial biofilms. The in-depth analysis of the antimicrobial mechanism confirmed that the conjugates can quickly bind on the bacterial surface, irreversibly disrupt the bacterial membrane, and distinctly inhibit intracellular enzyme activity, ultimately leading to the bacterial death. Importantly, these conjugates are highly selective toward bacterial cells over mammalian cells as well as no cytotoxicity to A549 cells and no discernible hemolytic activity. Collectively, this water-soluble galactose-decorated cationic BODIPY-based photodynamic therapy agent design provides promising insights for the development of therapy for antibiotic-resistant bacteria.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Compostos de Boro/farmacologia , Galactose/química , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacologia , Células A549 , Cátions , Membrana Celular/efeitos dos fármacos , Células Cultivadas , Humanos , Espécies Reativas de Oxigênio/metabolismo , Solubilidade , Água/química
17.
ACS Appl Mater Interfaces ; 9(36): 30470-30479, 2017 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-28832120

RESUMO

The emergence of antibiotic-resistant bacterial strains has made conventional antibiotic therapies less efficient. The development of a novel nanoantibiotic approach for efficiently ablating such bacterial infections is becoming crucial. Herein, a collection of poly(5-(2-ethyl acrylate)-4-methylthiazole-g-butyl)/copper sulfide nanoclusters (PATA-C4@CuS) was synthesized for efficient capture and effective ablation of levofloxacin-resistant Gram-negative and Gram-positive bacteria upon tissue-penetrable near-infrared (NIR) laser irradiation. In this work, we took advantage of the excellent photothermal and photodynamic properties of copper sulfide nanoparticles (CuSNPs) upon NIR laser irradiation and thiazole derivative as a membrane-targeting cationic ligand toward bacteria. The conjugated nanoclusters could anchor the bacteria to trigger the bacterial aggregation quickly and efficiently kill them. These conjugated nanoclusters could significantly inhibit levofloxacin-resistant Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Bacillus amyloliquefaciens at 5.5 µg/mL under NIR laser irradiation (980 nm, 1.5 W cm-2, 5 min), which suggested that the heat and reactive oxygen species (ROS) generated from the irradiated CuSNPs attached to bacteria were effective in eliminating and preventing the regrowth of the bacteria. Importantly, the conjugated nanoclusters could promote healing in bacteria-infected rat wounds without nonspecific damage to normal tissue. These findings highlight the promise of the highly versatile multifunctional nanoantibiotics in bacterial infection.


Assuntos
Farmacorresistência Bacteriana , Animais , Antibacterianos , Bactérias , Cobre , Nanoestruturas , Ratos , Sulfetos
18.
ACS Appl Mater Interfaces ; 9(20): 16834-16847, 2017 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-28481506

RESUMO

Biofilms' tolerance has become a serious clinical concern due to their formidable resistance to conventional antibiotics and prevalent virulence. Therefore, there is an urgent need to develop alternative antimicrobial agents to eradicate biofilms but avoid using antibiotics. Herein, we successfully developed polymer functional silver nanocomposites by reduction of silver nitrate in the presence of a biocompatible carbohydrate polymer and a membrane-disrupting cationic polymer. The nanocomposites presented effective antimicrobial activity against Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus and Bacillus amyloliquefaciens). Confocal laser scanning macroscopy imaging demonstrated that the nanocomposites could efficiently disperse and eradicate the mature biofilms formed by the above four bacterial strains. The introduction of carbohydrate polymers onto nanocomposites effectively improved the biocompatibility, and these nanocomposites induced no significant red blood cell hemolysis and cytotoxicity toward mammalian cells. More importantly, the nanocomposites were able to well eradicate the bacterial biofilms formed on the silicone implants in vivo. In conclusion, the nanocomposites as the broad-spectrum biofilm-disrupting agent are significant in the design of new strategies to eradicate biofilms on indwelling medical devices.


Assuntos
Nanocompostos , Animais , Antibacterianos , Biofilmes , Testes de Sensibilidade Microbiana , Staphylococcus aureus
19.
ACS Appl Mater Interfaces ; 9(16): 13837-13848, 2017 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-28383253

RESUMO

To explore the structure-activity relationship of membrane-targeting cationic ligands on a silver nanoparticle surface in an antibiotic-resistant antibacterial and antibiofilm activity assay, a series of functionalized silver nanocomposites were synthesized. Tuning the structural configuration, molecular weight, and side-chain length of the cationic ligands on the nanoparticle surface provided silver nanocomposites with effective antibacterial activity against both antibiotic-resistant Gram-negative and Gram-positive bacteria, including bacterial biofilms. These silver nanocomposites did not trigger hemolytic activity. Significantly, the bacteria did not develop resistance to the obtained nanocomposites even after 30 generations. A study of the antibacterial mechanism confirmed that these nanocomposites could irreversibly disrupt the membrane structure of bacteria and effectively inhibit intracellular enzyme activity, ultimately leading to bacterial death. The silver nanocomposites (64 µg/mL) could eradicate 80% of an established antibiotic-resistant bacterial biofilm. The strong structure-activity relationship toward antibacterial and antibiofilm activity suggests that variations in the conformational property of the functional ligand could be valuable in the discovery of new nano-antibacterial agents for treating pathogenic bacterial infections.


Assuntos
Nanocompostos , Antibacterianos , Biofilmes , Cátions , Farmacorresistência Bacteriana , Ligantes , Nanopartículas Metálicas , Prata , Relação Estrutura-Atividade
20.
ACS Appl Mater Interfaces ; 8(39): 25798-25807, 2016 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-27622986

RESUMO

With the increased prevalence of antibiotic-resistant bacteria infections, there is a pressed need for innovative antimicrobial agent. Here, we report a benign ε-polylysine/silver nanoparticle nanocomposite (EPL-g-butyl@AgNPs) with polyvalent and synergistic antibacterial effects. EPL-g-butyl@AgNPs exhibited good stability in aqueous solution and effective antibacterial activity against both Gram-negative (P. aeruginosa) and Gram-positive (S. aureus) bacteria without emergence of bacterial resistance. Importantly, the nanocomposites eradicated the antibiotic-resistant bacteria without toxicity to mammalian cells. Analysis of the antibacterial mechanism confirmed that the nanocomposites adhered to the bacterial surface, irreversibly disrupted the membrane structure of the bacteria, subsequently penetrated cells, and effectively inhibited protein activity, which ultimately led to bacteria apoptosis. Notably, the nanocomposites modulated the relative level of CD3+ T cells and CD68+ macrophages and effectively promoted infected wound healing in diabetic rats. This work improves our understanding of the antibacterial mechanism of AgNPs-based nanocomposites and offers guidance to activity prediction and rational design of effective antimicrobial nanoparticles.


Assuntos
Nanopartículas Metálicas , Animais , Antibacterianos , Anti-Infecciosos , Diabetes Mellitus Experimental , Testes de Sensibilidade Microbiana , Ratos , Prata , Staphylococcus aureus , Cicatrização
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