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1.
Acc Chem Res ; 56(7): 740-751, 2023 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-36920352

RESUMO

ConspectusSelf-assembly bridges nanoscale and microscale colloidal particles into macroscale functional materials. In particular, self-assembly processes occurring at the liquid/liquid or solid/liquid/air interfaces hold great promise in constructing large-scale two- or three-dimensional (2D or 3D) architectures. Interaction of colloidal particles in the assemblies leads to emergent collective properties not found in individual building blocks, offering a much larger parameter space to tune the material properties. Interfacial self-assembly methods are rapid, cost-effective, scalable, and compatible with existing fabrication technologies, thus promoting widespread interest in a broad range of research fields.Surface chemistry of nanoparticles plays a predominant role in driving the self-assembly of nanoparticles at water/oil interfaces. Amphiphilic nanoparticles coated with mixed polymer brushes or mussel-inspired polydopamine were demonstrated to self-assemble into closely packed thin films, enabling diverse applications from electrochemical sensors and catalysis to surface-enhanced optical properties. Interfacial assemblies of amphiphilic gold nanoparticles were integrated with graphene paper to obtain flexible electrodes in a modular approach. The robust, biocompatible electrodes with exceptional electrocatalytic activities showed excellent sensitivity and reproducibility in biosensing. Recyclable catalysts were prepared by transferring monolayer assemblies of polydopamine-coated nanocatalysts to both hydrophilic and hydrophobic substrates. The immobilized catalysts were easily recovered and recycled without loss of catalytic activity. Plasmonic nanoparticles were self-assembled into a plasmonic substrate for surface-enhanced Raman scattering, metal-enhanced fluorescence, and modulated fluorescence resonance energy transfer (FRET). Strong Raman enhancement was accomplished by rationally directing the Raman probes to the electromagnetic hotspots. Optimal enhancement of fluorescence and FRET was realized by precisely controlling the spacing between the metal surface and the fluorophores and tuning the surface plasmon resonance wavelength of the self-assembled substrate to match the optical properties of the fluorescent dye.At liquid/solid interfaces, infiltration-assisted (IFAST) colloidal self-assembly introduces liquid infiltration in the substrate as a new factor to control the degree of order of the colloidal assemblies. The strong infiltration flow leads to the formation of amorphous colloidal arrays that display noniridescent structural colors. This method is compatible with a broad range of colloidal particle inks, and any solid substrate that is permeable to dispersing liquids but particle-excluding is suitable for IFAST colloidal assembly. Therefore, the IFAST technology offers rapid, scalable fabrication of structural color patterns of diverse colloidal particles with full-spectrum coverage and unprecedented flexibility. Metal-organic framework particles with either spherical or polyhedral morphology were used as ink particles in the Mayer rod coating on wettability patterned photopapers, leading to amorphous photonic structures with vapor-responsive colors. Anticounterfeiting labels have also been developed based on the complex optical features encoded in the photonic structures.Interfacial colloidal self-assembly at the water/oil interface and IFAST assembly at the solid/liquid/air interface have proven to be versatile fabrication platforms to produce functional materials with well-defined properties for diverse applications. These platform technologies are promising in the manufacturing of value-added functional materials.

2.
Biomacromolecules ; 25(3): 2007-2015, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38349647

RESUMO

Chemoselective reactions allow near-precision control over the polymer composition and topology to create sequence-controlled polymers with similar secondary and tertiary structures to those found in proteins. Dendrimers are recognized as well-defined macromolecules with the potential to mimic protein surface functionality due to the large number of functional groups available at its periphery with the internal structure acting as the support scaffold. Transitioning from using small-molecule dendrimers to dendritic macromolecules will not only allow retention of the high peripheral functionality but also provide an internal scaffold with a desired polymer composition within each generational layer. Here, we exemplify a systematic approach to creating a dendritic macromolecule with the placement of different polymer building blocks in precise locations within the internal structure and the placement of three different amino acid moieties clustered at the periphery. The synthesis of this ABC dendritic macromolecule was accomplished through iterative chemoselective reactions.


Assuntos
Dendrímeros , Dendrímeros/química , Aminoácidos/química , Polímeros/química , Proteínas
3.
Macromol Rapid Commun ; 43(10): e2100812, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35394089

RESUMO

Cationic polymers are under intense research to achieve prominent antimicrobial activity. However, the cellular and in vivo toxicity caused by nonspecific electrostatic interaction has become a major challenge for their practical applications. Here, the development of a "caging" strategy based on the use of a block copolymer consisting of a stealth block and an anionic block that undergoes degradation in presence of enzymes secreted by selective bacterial pathogens of interest is reported. The results have shown that antimicrobial cationic polymer brushes-coated gold nanorods (AuNRs) can be caged by the block polymer of poly(ethylene glycol) and anionic, lipase-degradable block of ε-caprolactone and methacrylic acid copolymer to afford neutrally charged surfaces. The caged AuNRs are activated by lipase released by bacteria of interest to endow an excellent bactericidal effect but show minimal binding and toxicity against mammalian cells and nonspecific bacteria that do not produce lipase. In this design, AuNRs play multifunctional roles as the scaffolds for polymer brushes, photothermal transducers, and imaging probes for traceable delivery of the activation and delivery of bactericidal cationic polymer brushes. The caging strategy opens new opportunities for the safe delivery of antimicrobial materials for the treatment of bacterial infections.


Assuntos
Nanoestruturas , Polímeros , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Bactérias , Cátions , Lipase , Mamíferos , Nanoestruturas/química , Polietilenoglicóis/química , Polímeros/química , Polímeros/farmacologia
4.
Small ; 17(2): e2006357, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33325629

RESUMO

Nanoparticles have been widely used in detection and killing of bacteria; however, targeting bacteria is still challenging. Delicate design of nanoparticles is required for simultaneous targeting, detection, and therapeutic functions. Here the use of Au/MnFe2 O4 (Au/MFO) Janus nanoparticles to target Gram-positive bacteria via metabolic labeling is reported and realize integrated self-reporting and thermal killing of bacteria. In these nanoparticles, the Au component is functionalized with tetrazine to target trans-cyclooctene group anchored on bacterial cell wall by metabolic incorporation of d-amino acids, and the MFO part exhibits peroxidase activity, enabling self-reporting of bacteria before treatment. The spatial separation of targeting and reporting functions avoids the deterioration of catalytic activity after surface modification. Also important is that MFO facilitates magnetic separation and magnetic heating, leading to easy enrichment and magnetic thermal therapy of labeled bacteria. This method demonstrates that metabolic labeling with d-amino acids is a promising strategy to specifically target and kill Gram-positive bacteria.


Assuntos
Nanopartículas de Magnetita , Nanopartículas Multifuncionais , Nanopartículas , Bactérias Gram-Positivas , Magnetismo
5.
Nano Lett ; 20(11): 8120-8126, 2020 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-33135902

RESUMO

Ultrathin, ultrastrong, and highly conductive solid-state polymer-based composite electrolytes have long been exploited for the next-generation lithium-based batteries. In particular, the lightweight membranes that are less than tens of microns are strongly desired, aiming to maximize the energy densities of solid-state batteries. However, building such ideal membranes are challenging when using traditional materials and fabrication technologies. Here we reported a 7.1 µm thick heterolayered Kevlar/covalent organic framework (COF) composite membrane fabricated via a bottom-up spin layer-by-layer assembly technology that allows for precise control over the structure and thickness of the obtained membrane. Much stronger chemical/mechanical interactions between cross-linked Kevlar and conductive 2D-COF building blocks were designed, resulting in a highly strong and Li+ conductive (1.62 × 10-4 S cm-1 at 30 °C and 4.6 × 10-4 S cm-1 at 70 °C) electrolyte membrane that can prevent solid-state batteries from short-circuiting after over 500 h of cycling. All-solid-state lithium batteries using this membrane enable a significantly improved energy density.

6.
Nano Lett ; 20(3): 2191-2196, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32059111

RESUMO

The typical polymer electrolyte matrix has been limited to the chains consisting of -C-C- or -C-O-C- or -Si-O- backbone with different solvating groups for decades. In this work, the polymeric sulfur consisting of -(S-S)n- backbone with a high sulfur content (up to 90 wt % S) was reported for the first time. The flexible -(S-S)n- chains with high S atom density create an intense "solvating" environment for Li+ conduction, achieving an excellent Li+ conductivity of 1.69 × 10-3 S cm-1 at 80 °C. Benefiting from its unique thermoplasticity, a hot-rolling process was also developed for fabricating the poly-S membrane. The symmetric solid-state Li cell using the membrane showed a high cycling stability over 300 h. The work offers a novel platform for chemists to design new polymer electrolytes that are quite different with conventional carbon-based polymer electrolytes.

7.
Nano Lett ; 19(4): 2343-2349, 2019 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-30856336

RESUMO

In recent years solid Li+ conductors with competitive ionic conductivity to those of liquid electrolytes have been reported. However, the incorporation of highly conductive solid electrolytes into the lithium-ion batteries is still very challenging mainly due to the high resistance existing at the solid-solid interfaces throughout the battery structure. Here, we demonstrated a universal interfacial modification strategy through coating a curable polymer-based glue electrolyte between the electrolyte and electrodes, aiming to address the poor solid-solid contact and thus decrease high interfacial resistance. The liquid glue exhibits both great wettability as well as chemical/electrochemical stability to most of the electrodes, and it can be easily solidified into a polymer electrolyte layer through a "post-curing" treatment. As a result, symmetric Li batteries with the glue modification exhibit much smaller impedance and enhanced stability upon plating/stripping cycles compared to the batteries without glue modification. The all-solid-state Li-S batteries with glue modification show significantly enhanced performances. The strategy of developing glue electrolytes to improve the electrode-electrolyte interface contact provides an alternative option for improving many other solid-state batteries.

8.
Macromol Rapid Commun ; 40(1): e1800613, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30456873

RESUMO

Self-assembly of plasmonic nanocrystals (PNCs) and polymers provides access to a variety of functionalized metallic-polymer building blocks and higher-order hybrid plasmonic assemblies, and thus is of considerable fundamental and practical interest. The hybrid assemblies often not only inherit individual characteristics of polymers and PNCs but also exhibit distinct photophysical and catalytic properties compared to that of a single PNC building block. The tailorable plasmonic coupling between PNCs within assemblies enables the precise control over localized surface plasmon resonance, which subsequently affords a series of light-driven or photo-activated applications, such as surface-enhanced Raman scattering detection, photoacoustic imaging, photothermal therapy, and photodynamic therapy. In this review, the synthetic strategies of a library of PNC-polymer hybrid building blocks and corresponding assemblies are summarized along with the mechanisms of polymer-assisted self-assembly of PNCs and the concepts for bridging the intrinsic properties of PNC-polymer assemblies to widespread practical applications.


Assuntos
Nanopartículas/química , Polímeros/síntese química , Polímeros/química
9.
Biomacromolecules ; 19(2): 616-625, 2018 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-29283562

RESUMO

Cyclic polymers with internal constraints provide new insight into polymer properties in solution and bulk and can serve as a model system to explain the stability and mobility of cyclic biomacromolecules. The model system used in this work consisted of cyclic polystyrene structures, all with a nearly identical molecular weight, designed with 0-3 constraints located at strategic sites within the cyclic polymer, with either 4 or 6 branch points. The total number of branch points (or arms) within the cyclic ranged from 0 to 18. Molecular dynamic (MD) simulations showed that as the number of arms increased within the cyclic structure, the radius of gyration and the hydrodynamic radius generally decreased, suggesting the greater number of constraints resulted in a more compact polymer chain. The simulations further showed that the excluded volume was much greater for the cyclics compared to a linear polymer at the same molecular weight. The spirocyclic, a structure consisting of three rings joined in series, showed significant excluded volume effects in agreement with experimental data; the reason for which is unclear at this stage. Interestingly, under a size exclusion chromatography flow, the radius of hydration for all the cyclic structures increased compared with the DLS data, and could be explained from the greater swelling of the rings perpendicular to the flow found from previous simulations on rings. This data suggests that the greater compactness, greater excluded volume and structural rearrangements under flow of constrained cyclic polymers could be used to provide a physical basis for understanding greater stability and activity of cyclic biological macromolecules.


Assuntos
Simulação de Dinâmica Molecular , Polímeros/química , Estrutura Molecular
10.
Pharmazie ; 69(8): 629-32, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25158575

RESUMO

Icotinib, a selective EGFR tyrosine kinase inhibitor (EGFR-TKI), has been shown to exhibit anti-tumor activity against several tumor cell lines. However, the exact molecular mechanism of icotinib's anti-tumor effect remains unknown. This study aims to examine the zytotoxic effect of icotinib on Tca8113 cells and its potential molecular mechanism. Icotinib significantly resulted in dose-dependent cell death as determined by MTT assay, accompanied by increased levels of Bax and DNA fragmentation. Icotinib could also induce Reactive Oxygen Species (ROS) generation. Further studies confirmed that scavenging of reactive oxygen species by N-acetyl-L-cysteine (NAC), and pharmacological inhibition of MAPK reversed icotinib-induced apoptosis in Tca8113 cells. Our data provide evidence that icotinib induces apoptosis, possibly via ROS-mediated MAPK pathway in Tca8113 cells.


Assuntos
Apoptose/efeitos dos fármacos , Éteres de Coroa/farmacologia , Quinazolinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Ativação Enzimática/efeitos dos fármacos , Humanos , Estresse Oxidativo/efeitos dos fármacos
11.
Biomater Sci ; 11(2): 356-379, 2023 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-36408610

RESUMO

Bacterial infection is one of the leading causes of death globally, although modern medicine has made considerable strides in the past century. As traditional antibiotics are suffering from the emergence of drug resistance, new antibacterial strategies are of great interest. Responsive materials are appealing alternatives that have shown great potential in combating resistant bacteria and avoiding the side effects of traditional antibiotics. In this review, the responsive antibacterial materials are introduced in terms of stimulus signals including intrinsic (pH, enzyme, ROS, etc.) and extrinsic (light, temperature, magnetic fields, etc.) stimuli. Their biomedical applications in therapeutics and medical devices are then discussed. Finally, the author's perspective of the challenge and the future of such a system is provided.


Assuntos
Bactérias , Infecções Bacterianas , Humanos , Infecções Bacterianas/tratamento farmacológico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Temperatura
12.
Zhonghua Gan Zang Bing Za Zhi ; 19(4): 297-300, 2011 Apr.
Artigo em Zh | MEDLINE | ID: mdl-21586230

RESUMO

OBJECTIVE: To evaluate the significance of determining ascitic bacterial 16S rRNA by quantitative PCR combined with microarray (PCR-microarray) in the diagnosis of spontaneous bacterial peritonitis (SBP). METHODS: Ascitic bacterial 16SrRNA was determined by real time fluorescent quantitative PCR-microarray in 76 cases of suspected SBP and 6 cases of non-infectious ascites with chronic liver diseases. The results were compared with ascitic bacterial culture simultaneously. RESULTS: Of 76 ascitic samples, 17 were detected bacteria positive by PCR-microarray, including 8 Grams positive(G+) and 9 Grams negative(G-), which was higher than that by bacterial culture which had only 6 ascitic samples detected positive (all G-); the positive rates were 22.4% vs 7.9%, respectively (P < 0.01). The bacterial strains detected by both methods in 6 cases had a consistency with each other. No bacteria were detected in another 6 cases of non-infectious ascites with chronic liver diseases. CONCLUSIONS: Determination of ascitic bacteria 16S rRNA by PCR-microarray has a higher specificity and sensitivity in the diagnosis of SBP as compared with the bacteria culture. Application of this novel method can not only accelerate SBP diagnosis but also stratify the different pathogens.


Assuntos
Líquido Ascítico/microbiologia , Infecções Bacterianas/diagnóstico , Peritonite/diagnóstico , Adulto , Idoso , Infecções Bacterianas/microbiologia , Feminino , Humanos , Cirrose Hepática/diagnóstico , Cirrose Hepática/microbiologia , Masculino , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Peritonite/microbiologia , Reação em Cadeia da Polimerase/métodos , RNA Bacteriano/isolamento & purificação , RNA Ribossômico 16S/isolamento & purificação
13.
Anal Chim Acta ; 1166: 338567, 2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34022991

RESUMO

Acute myocardial infarction (AMI) is the leading cause of morbidity and mortality globally. The serum levels of a group of cardiac biomarkers have been regarded as important indicators in the routine diagnosis of AMI. The development of rapid, sensitive, and accurate detection methods of AMI biomarkers is urgently needed for the early diagnosis of AMI. Here, a dynamic and pseudo-homogeneous enzyme-linked immunosorbent assay (ELISA) was reported based on the combined use of bioconjugated magnetic nanochains (MNCs) and gold nanoparticles (AuNPs) probes. The capture antibodies-conjugated MNCs served as dynamic nano-mixers to facilitate liquid mixing and as homogeneously dispersed capturing agents to capture and separate specific targets. The AuNPs probes were prepared by co-immobilization of detection antibodies and horseradish peroxidase (HRP) for signals amplification. The design of bioconjugated MNCs and AuNPs probes significantly increased the assay kinetics and improves the assay sensitivity. This novel ELISA strategy realized accurate detection of a panel of AMI biomarkers within 35 min, leading to considerably improved sensitivities compared to that of conventional ELISA method.


Assuntos
Nanopartículas Metálicas , Infarto do Miocárdio , Biomarcadores , Ensaio de Imunoadsorção Enzimática , Ouro , Peroxidase do Rábano Silvestre , Humanos , Fenômenos Magnéticos , Infarto do Miocárdio/diagnóstico
14.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 32(5): 557-60, 2010 Oct.
Artigo em Zh | MEDLINE | ID: mdl-21050561

RESUMO

OBJECTIVE: To evaluate the value of ascitic bacterial 16S rRNA gene determination in the rapid diagnosis of spontaneous bacterial peritonitis (SBP). METHODS: 16S rRNA gene from bacterial DNA in ascites was determined by quantitative fluorescent polymerase chain reaction (PCR) in 76 patients with suspected SBP and 6 patients with non-infectious ascites. The results were compared with those obtained from bacterial culture. RESULTS: The positive rate of SBP was 22.4% among patients detected with ascitic bacterial 16S rRNA gene determination-based quantitative fluorescent PCR, which was significantly higher than that (7.9%) in patients only received bacterial culture (P<0.05). In addition,in 6 patients with non-infectious ascites,both the 16S rRNA gene determination-based quantitative fluorescent PCR and bacterial culture showed negative results. CONCLUSIONS: 16S rRNA gene determination-based quantitative fluorescent PCR can be an effective tool for the rapid diagnosis of SBP. It is more sensitive than the bacterial culture.


Assuntos
Líquido Ascítico/microbiologia , Infecções Bacterianas/diagnóstico , Peritonite/diagnóstico , RNA Ribossômico 16S , Adulto , Idoso , DNA Bacteriano/análise , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peritonite/microbiologia
15.
Adv Mater ; 32(8): e1906475, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31943423

RESUMO

Fluorescence resonance energy transfer (FRET) has found widespread uses in biosensing, molecular imaging, and light harvesting. Plasmonic metal nanostructures offer the possibility of engineering photonic environment of specific fluorophores to enhance the FRET efficiency. However, the potential of plasmonic nanostructures to enable tailored FRET enhancement on planar substrates remains largely unrealized, which are of considerable interest for high-performance on-surface bioassays and photovoltaics. The main challenge lies in the necessitated concurrent control over the spectral properties of plasmonic substrates to match that of fluorophores and the fluorophore-substrate spacing. Here, a self-assembled plasmonic substrate based on polydopamine (PDA)-coated plasmonic nanocrystals is developed to effectively address this challenge. The PDA coating not only drives interfacial self-assembly of the nanocrystals to form closely packed arrays with customized optical properties, but also can serve as a tailored nanoscale spacer between the fluorophores and plasmonic nanocrystals, which collectively lead to optimized fluorescence enhancement. The biocompatible plasmonic substrate that allows convenient bioconjugation imparted by PDA has afforded improved FRET efficiency in DNA microarray assay and FRET imaging of live cells. It is envisioned that the self-assembled plasmonic substrates can be readily integrated into fluorescence-based platforms for diverse biomedical and photoconversion applications.


Assuntos
Materiais Biocompatíveis/química , Transferência Ressonante de Energia de Fluorescência , Carbocianinas/química , Linhagem Celular Tumoral , Fator de Crescimento Epidérmico/química , Corantes Fluorescentes/química , Ouro/química , Humanos , Indóis/química , Nanopartículas Metálicas/química , Microscopia Confocal , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Polímeros/química , Prata/química
16.
Adv Mater ; 31(44): e1902733, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31463987

RESUMO

The synthesis of well-defined inorganic colloidal nanostructures using functional macromolecules is an enabling technology that offers the possibility of fine-tuning the physicochemical properties of nanomaterials and has contributed to a broad range of practical applications. The utilization of functional reactive polymers and their colloidal assemblies leads to a high level of control over structural parameters of inorganic nanoparticles that are not easily accessible by conventional methods based on small-molecule ligands. Recent advances in polymerization techniques for synthetic polymers and newly exploited functions of natural biomacromolecules have opened up new avenues to monodisperse and multifunctional nanostructures consisting of integrated components with distinct chemistries but complementary properties. Here, the evolution of colloidal synthesis of inorganic nanoparticles is revisited. Then, the new developments of colloidal synthesis enabled by functional macromolecules and practical applications associated with the resulting optical, catalytic, and structural properties of colloidal nanostructures are summarized. Finally, a perspective on new and promising pathways to novel colloidal nanostructures built upon the continuous development of polymer chemistry, colloidal science, and nanochemistry is provided.

17.
Zhonghua Yu Fang Yi Xue Za Zhi ; 42(8): 596-8, 2008 Aug.
Artigo em Zh | MEDLINE | ID: mdl-19115625

RESUMO

OBJECTIVE: To discuss the significance of testing hepatitis B virus (HBV) from saliva in HBV patients. METHODS: HBV DNA content in serum and saliva of 200 HBV patients and 20 healthy subjects were detected by fluorescence quantitative polymerase chain reaction. According to the serum level of HBV content, four groups were divided: control group A, group B negative, low virus C (1 x 10(3) - 1 x 10(5) copies/ml) and high-group D ( > 1 x 10(5) copies/ml). The relationship of serum and virus content in saliva was analysed. RESULTS: Of 200 HBV cases, 180 were found HBV DNA in serum with positive rate of 90.0%; while 145 were found HBV DNA in saliva with positive rate of 72.5%, and there was no significant difference (chi2 = 1.35, P > 0.05). The significant difference was observed in testing serum and saliva in Group C (100.0% vs. 38.5%; Z = 14.11, P < 0.01). In group D, there was no significant difference found either (100.0% vs. 83.8%; chi2 = 1.05, P > 0.05). Group D virus serum had a high average level of (6.63 +/- 1.55) log copies/ml virus and in the saliva had an average level of (5.21 +/- 1.85) log copies/ml; saliva had serum viral load lower than an order of magnitude average. No HBV DNA was found in serum or saliva from 20 health subjects. CONCLUSION: When the serum contains a high content of HBV DNA virus, the content of saliva HBV DNA virus should be likely high, which might pose a threat of source of infection. A precise quantitative detection of HBV DNA in saliva might be used as evaluation of the level of virus in the body copy for judgment of infection.


Assuntos
DNA Viral/análise , Hepatite B/transmissão , Saliva/virologia , Estudos de Casos e Controles , DNA Viral/sangue , Feminino , Hepatite B/diagnóstico , Vírus da Hepatite B/genética , Humanos , Masculino
18.
Zhonghua Gan Zang Bing Za Zhi ; 15(8): 582-4, 2007 Aug.
Artigo em Zh | MEDLINE | ID: mdl-17711626

RESUMO

OBJECTIVE: This study aimed to assess the clinical significance of intrahepatic hepatitis B core antigen (HBcAg) (+) in patients with chronic hepatitis B (CHB). METHODS: 200 CHB patients were prospectively studied using fluorescence quantitative PCR (FQ-PCR), combined PCR with fluorescence probe hybridization technique, to determine serum HBV DNA. Serum HBeAg was measured quantitatively. Liver biopsies were performed and immunohistochemistry stained liver slides were examined in all the cases. Correlation analyses were performed. RESULTS: Based on the HBV DNA levels, the patients were divided into 5 groups: group A (<3 log10 copies/ml) n=20, group B (>or=3 log10 copies/ml-<5 log10 copies/ml) n=13, group C (>or=5 log10 copies/ml-<6 log10 copies/ml) n=24, group D (>or=6 log10 copies/ml-<8 log10 copies/ml) n=116, and group E (>or=8 log10 copies/ml) n=27, and 87.5% of the CHB patients were intrahepatic HBcAg (+). The rate of HBcAg (+) was 55.0% (11/20) in group A, 53.8% (7/13) in group B, 75.0% (19/24) in group C, 96.6% (112/116) in group D, and 100% (27/27) in group E. A strong correlation was found between the rate of HBcAg (+) and the level of serum HBV DNA (r=0.80). This type of association also appeared between serum HBV DNA levels and HBeAg (+) (r=0.47). Of 20 CHB patients who were serum HBV DNA negative, 25% (5) were HBeAg (+), and 55% (11) were HBcAg (+), whereas 15 patients were both HBV DNA (-) and HBeAg (-), and 46.7% (7) were HBcAg (+). CONCLUSIONS: Intrahepatic HBcAg (+) in CHB patients might be more reliable in reflecting HBV replication. Determination of HBcAg (+) may have clinical significance for evaluating the efficacy of antiviral therapy and for predicting the therapeutic responses to different antiviral agents.


Assuntos
Antígenos do Núcleo do Vírus da Hepatite B/análise , Hepatite B Crônica/virologia , Fígado/virologia , Adulto , DNA Viral/sangue , Feminino , Vírus da Hepatite B/imunologia , Vírus da Hepatite B/fisiologia , Hepatite B Crônica/imunologia , Humanos , Masculino , Replicação Viral , Adulto Jovem
19.
Mol Med Rep ; 13(1): 543-9, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26549420

RESUMO

The loss of neurotrophic factor support has been shown to contribute to the development of the central nervous system. Glial cell line­derived neurotrophic factor (GDNF), a potent neurotrophic factor, is closely associated with apoptosis and exerts neuroprotective effects on numerous populations of cells. However, the underlying mechanisms of these protective effects remain unknown. In the present study, a significant increase in Bax levels and DNA fragmentation was observed in the hippocampus obtained from the brains of diabetic rats 60 days after diabetes had been induced. The apoptotic changes were correlated with the loss of GDNF/Akt signaling. GDNF administration was found to reverse the diabetes­induced Bax and DNA fragmentation changes. This was associated with an improvement in the level of p­Akt/Akt. In addition, combination of GDNF with a specific inhibitor of the phosphoinositide 3­kinase (PI3K)/Akt pathway, Wortmannin, significantly abrogated the effects of GDNF on the levels of p­Akt/Akt, Bax and DNA fragmentation. However, a p38 mitogen­activated proten kinase (MAPK) inhibitor, SB203580, had no effect on the expression of p­Akt/Akt, Bax or DNA fragmentation. These results demonstrate the pivotal role of GDNF as well as the PI3K/Akt pathway, but not the MAPK pathway, in the prevention of diabetes­induced neuronal apoptosis in the hippocampus.


Assuntos
Apoptose/efeitos dos fármacos , Encefalopatias/patologia , Diabetes Mellitus Experimental/patologia , Fator Neurotrófico Derivado de Linhagem de Célula Glial/farmacologia , Hipocampo/patologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Regulação para Cima/efeitos dos fármacos , Animais , Encefalopatias/complicações , Fragmentação do DNA/efeitos dos fármacos , Diabetes Mellitus Experimental/complicações , Ativação Enzimática/efeitos dos fármacos , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Ratos Sprague-Dawley , Estreptozocina , Proteína X Associada a bcl-2/metabolismo
20.
PLoS One ; 11(3): e0152169, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27007701

RESUMO

Four end-functionalized star polymers that could attenuate the flow of ionic currents across biological ion channels were first de novo designed computationally, then synthesized and tested experimentally on mammalian K+ channels. The 4-arm ethylene glycol conjugate star polymers with lysine or a tripeptide attached to the end of each arm were specifically designed to mimic the action of scorpion toxins on K+ channels. Molecular dynamics simulations showed that the lysine side chain of the polymers physically occludes the pore of Kv1.3, a target for immuno-suppression therapy. Two of the compounds tested were potent inhibitors of Kv1.3. The dissociation constants of these two compounds were computed to be 0.1 µM and 0.7 µM, respectively, within 3-fold to the values derived from subsequent experiments. These results demonstrate the power of computational methods in molecular design and the potential of star polymers as a new infinitely modifiable platform for ion channel drug discovery.


Assuntos
Canais Iônicos/efeitos dos fármacos , Peptidomiméticos/farmacologia , Charibdotoxina/farmacologia , Eletrofisiologia , Células HEK293/efeitos dos fármacos , Humanos , Canal de Potássio Kv1.3/efeitos dos fármacos , Polímeros/farmacologia , Canais de Potássio/efeitos dos fármacos , Relação Estrutura-Atividade
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