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1.
Pharm Res ; 40(9): 2103-2106, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37349651

RESUMO

The goal of pharmacovigilance (PV) is to prevent adverse events (AEs) associated with drugs and vaccines. Current PV programs are of a reactive nature and rest entirely on data science, i.e., detecting and analyzing AE data from provider/patient reports, health records and even social media. The ensuing preventive actions are too late for people who have experienced AEs and often overly broad, as responses include entire product withdrawals, batch recalls, or contraindications of subpopulations. To prevent AEs in a timely and precise manner, it is necessary to go beyond data science and incorporate measurement science into PV efforts through person-level patient screening and dose-level product surveillance. Measurement-based PV may be called 'preventive pharmacovigilance', the goal of which is to identify susceptible individuals and defective doses to prevent AEs. A comprehensive PV program should contain both reactive and preventive components by integrating data science and measurement science.


Assuntos
Farmacovigilância , Vacinas , Humanos , Vacinas/efeitos adversos
2.
Pharm Res ; 40(6): 1435-1446, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36414838

RESUMO

This study applies an emerging analytical technology, wNMR (water proton nuclear magnetic resonance), to assess the stability of aluminum adjuvants and antigen-adjuvant complexes against physical stresses, including gravitation, flow and freeze/thaw. Results from wNMR are verified by conventional analytical technologies, including static light scattering and microfluidic imaging. The results show that wNMR can quickly and noninvasively determine whether an aluminum adjuvant or antigen-adjuvant complex sample has been altered by physical stresses.


Assuntos
Adjuvantes Imunológicos , Alumínio , Alumínio/química , Adjuvantes Imunológicos/química , Antígenos/química
3.
Molecules ; 28(7)2023 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-37049879

RESUMO

An NMR method based on the gradient-based broadening fingerprint using line shape enhancement (PROFILE) is put forward to precisely and sensitively study hydrogel swelling under restricted conditions. This approach achieves a match between the resonance frequency and spatial position of the sample. A three-component hydrogel with salt ions was designed and synthesized to show the monitoring more clearly. The relationship between the hydrogel swelling and the frequency signal is revealed through the one-dimensional imaging. This method enables real-time monitoring and avoids changing the swelling environment of the hydrogel during contact. The accuracy of this method may reach the micron order. This finding provides an approach to the rapid and non-destructive detection of swelling, especially one-dimensional swelling, and may show the material exchange between the hydrogel and swelling medium.

4.
BMC Pulm Med ; 22(1): 337, 2022 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-36071420

RESUMO

BACKGROUND: The optimum timing to wean is crucial to avoid negative outcomes for mechanically ventilated patients. The rapid shallow breathing index (RSBI), a widely used weaning index, has limitations in predicting weaning outcomes. By replacing the tidal volume of the RSBI with diaphragmatic excursion (DE) and diaphragm thickening fraction (DTF) assessed by ultrasonography, we calculated two weaning indices, the diaphragmatic excursion rapid shallow breathing index (DE-RSBI, respiratory rate [RR]/DE) and the diaphragm thickening fraction rapid shallow breathing index (DTF-RSBI, RR/DTF). The aim of this study was to evaluate the predictive values of DTF-RSBI, DE-RSBI and traditional RSBI in weaning failure. METHODS: This prospective observational study included patients undergoing mechanical ventilation (MV) for > 48 h and who were readied for weaning. During a pressure support ventilation (PSV) spontaneous breathing trial (SBT), right hemidiaphragmatic excursion and DTF were measured by bedside ultrasonography as well as RSBI. Weaning failure was defined as: (1) failing the SBT and (2) SBT success but inability to maintain spontaneous breathing for more than 48 h without noninvasive or invasive ventilation. A receiver operator characteristic (ROC) curve was used for analyzing the diagnostic accuracy of RSBI, DE-RSBI, and DTF-RSBI. RESULTS: Of the 110 patients studied, 37 patients (33.6%) failed weaning. The area under the ROC (AUROC) curves for RSBI, DE-RSBI, and DTF-RSBI for predicting failed weaning were 0.639, 0.813, and 0.859, respectively. The AUROC curves for DE-RSBI and DTF-RSBI were significantly higher than for RSBI (P = 0.004 and P < 0.001, respectively). The best cut-off values for predicting failed weaning were RSBI > 51.2 breaths/min/L, DE-RSBI > 1.38 breaths/min/mm, and DTF-RSBI > 78.1 breaths/min/%. CONCLUSIONS: In this study, two weaning indices determined by bedside ultrasonography, the DE-RSBI (RR/DE) and DTF-RSBI (RR/DTF), were shown to be more accurate than the traditional RSBI (RR/VT) in predicting weaning outcome during a PSV SBT.


Assuntos
Diafragma , Desmame do Respirador , Diafragma/diagnóstico por imagem , Humanos , Respiração , Respiração Artificial , Ultrassonografia
5.
Anal Chem ; 93(48): 15816-15820, 2021 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-34792343

RESUMO

The present work reports an enabling novel technology for quantifying the gene content in adeno-associated viral capsids. The method is based on the water proton nuclear magnetic resonance (wNMR) technique. Instead of analyzing the capsid directly, it utilizes water molecules to distinguish empty and full capsids, as water interacts with them differently. The transverse relaxation rate of water protons, R2(1H2O), readily distinguishes empty and full capsids and is capable of quantifying the fraction of full capsids in a mixture of full and empty ones. It involves no sample preparation and no reagents. Measurement is rapid (data collection takes 1-2 min), noninvasive (the capsid sample can stay inside the original sealed and labeled container to be used in other studies or administered to a patient), and performed using a wide-bore benchtop NMR instrument. The method can be readily implemented at a production plant for product release as part of product quality control.


Assuntos
Capsídeo , Prótons , Dependovirus , Humanos , Espectroscopia de Ressonância Magnética , Água
6.
Mol Pharm ; 18(4): 1544-1557, 2021 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-33621099

RESUMO

Complex iron nanoparticle-based drugs are one of the oldest and most frequently administered classes of nanomedicines. In the US, there are seven FDA-approved iron nanoparticle reference drug products, of which one also has an approved generic drug product (i.e., sodium ferric gluconate (SFG)). These products are indicated for the treatment of iron deficiency anemia and are administered intravenously. On the molecular level, iron nanomedicines are colloids composed of an iron oxide core with a carbohydrate coating. This formulation makes nanomedicines more complex than conventional small molecule drugs. As such, these products are often referred to as nonbiological complex drugs (e.g., by the nonbiological complex drugs (NBCD) working group) or complex drug products (e.g., by the FDA). Herein, we report a comprehensive study of the physiochemical properties of the iron nanoparticle product SFG. SFG is the single drug for which both an innovator (Ferrlecit) and generic product are available in the US, allowing for comparative studies to be performed. Measurements focused on the iron core of SFG included optical spectroscopy, inductively coupled plasma mass spectrometry (ICP-MS), X-ray powder diffraction (XRPD), 57Fe Mössbauer spectroscopy, and X-ray absorbance spectroscopy (XAS). The analysis revealed similar ferric-iron-oxide structures. Measurements focused on the carbohydrate shell comprised of the gluconate ligands included forced acid degradation, dynamic light scattering (DLS), analytical ultracentrifugation (AUC), and gel permeation chromatography (GPC). Such analysis revealed differences in composition for the innovator versus the generic SFG. These studies have the potential to contribute to future quality assessment of iron complex products and will inform on a pharmacokinetic study of two therapeutically equivalent iron gluconate products.


Assuntos
Medicamentos Genéricos/química , Compostos Férricos/química , Nanopartículas/química , Anemia Ferropriva/tratamento farmacológico , Química Farmacêutica , Cromatografia em Gel , Medicamentos Genéricos/administração & dosagem , Medicamentos Genéricos/farmacocinética , Medicamentos Genéricos/normas , Difusão Dinâmica da Luz , Estudos de Equivalência como Asunto , Compostos Férricos/administração & dosagem , Compostos Férricos/farmacocinética , Compostos Férricos/normas , Humanos , Nanopartículas/administração & dosagem , Nanopartículas/normas , Controle de Qualidade , Ultracentrifugação
7.
Pharm Res ; 38(1): 3-7, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33555493

RESUMO

Biologics are complex pharmaceuticals that include formulated proteins, plasma products, vaccines, cell and gene therapy products, and biological tissues. These products are fragile and typically require cold chain for their delivery and storage. Delivering biologics, while maintaining the cold chain, whether standard (2°C to 8°C) or deepfreeze (as cold as -70°C), requires extensive infrastructure that is expensive to build and maintain. This poses a huge challenge to equitable healthcare delivery, especially during a global pandemic. Even when the infrastructure is in place, breaches of the cold chain are common. Such breaches may damage the product, making therapeutics and vaccines ineffective or even harmful. Rather than strengthening the cold chain through building more infrastructure and imposing more stringent guidelines, we suggest that money and effort are best spent on making the cold chain unnecessary for biologics delivery and storage. To meet this grand challenge in pharmaceutical research, we highlight areas where innovations are needed in the design, formulation and biomanufacturing of biologics, including point-of-care manufacturing and inspection. These technological innovations would rely on fundamental advances in our understanding of biomolecules and cells.


Assuntos
Produtos Biológicos/normas , COVID-19/terapia , Pesquisa Farmacêutica/normas , Refrigeração/normas , Produtos Biológicos/uso terapêutico , COVID-19/epidemiologia , Humanos , Pesquisa Farmacêutica/tendências , Refrigeração/tendências , Vacinas/normas , Vacinas/uso terapêutico
8.
Magn Reson Chem ; 59(2): 147-161, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32888244

RESUMO

Suspensions of solid particles find applications in many areas-mining, waste treatment, and in pharmaceutical formulations. Pharmaceutical suspensions include aluminum-adjuvanted vaccines are widely administered to millions of people worldwide annually. Hence, the stability parameters of such suspensions, for example, sedimentation rate and the compactness of the formed sediments, are of great interest to achieve the most optimal and stable formulations. Unlike currently used analytical techniques involving visual observations and/or monitoring of several optical properties using specialized glassware, water proton nuclear magnetic resonance (wNMR) used in this work allows one to analyze samples in their original sealed container regardless of its opacity and/or labeling. It was demonstrated that the water proton transverse relaxation rate could be used to monitor in real time the sedimentation process of two widely used aluminum adjuvants-Alhydrogel® and Adju-Phos®. Using wNMR, we obtained valuable information on the sedimentation rate, dynamics of the supernatant and sediment formation, and the sedimentation volume ratio (SVR) reflecting the compactness of the formed sediment. Results on SVR from wNMR were verified by caliper measurements. Verification of the sedimentation rate results from wNMR by other analytical techniques is challenging due to differences in the measured attributes and even units of the reported rate. Nonetheless, our results demonstrate the practical applicability of wNMR as an analytical tool to study pharmaceutical suspensions, for example, aluminum-adjuvanted vaccines, to provide higher quality and more efficient vaccines. Such analyses could be carried out in the original container of a suspension drug product to study its colloidal stability and to monitor its quality over time without compromising product integrity.


Assuntos
Adjuvantes Imunológicos/química , Compostos de Alumínio/química , Hidróxido de Alumínio/química , Fosfatos/química , Água/química , Cinética , Fenômenos Físicos , Espectroscopia de Prótons por Ressonância Magnética
9.
Med Sci Monit ; 26: e925047, 2020 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-32720649

RESUMO

BACKGROUND The aim of this study was to describe the clinical characteristics and outcomes of patients with coronavirus disease 2019 (COVID-19) and compare these parameters in an elderly group with those in a younger group. MATERIAL AND METHODS This retrospective, single-center observational study included 69 hospitalized patients with laboratory-confirmed COVID-19 from a tertiary hospital in Wuhan, China, between January 14, 2020, and February 26, 2020. Epidemiological, demographic, clinical, and laboratory data, as well as treatments, complications, and outcomes were extracted from electronic medical records and compared between elderly patients (aged ≥60 years) and younger patients (aged <60 years). Patients were followed until March 19, 2020. RESULTS Elderly patients had more complications than younger patients, including acute respiratory distress syndrome (ARDS; 9/25, 36% vs. 5/44, 11.4%) and cardiac injury (7/25, 28% vs. 1/44, 2.3%), and they were more likely to be admitted to the intensive care unit (6/25, 24% vs. 2/44, 4.5%). As of March 19, 2020, 60/69 (87%) of the patients had been discharged, 6/69 (8.7%) had died, and 3/69 (4.3%) remained in the hospital. Of those who were discharged or died, the median duration of hospitalization was 13.5 days (interquartile range, 10-18 days). CONCLUSIONS Elderly patients with confirmed COVID-19 were more likely to develop ARDS and cardiac injury than younger patients and were more likely to be admitted to the intensive care unit. In addition to routine monitoring and respiratory support, cardiac monitoring and supportive care should be a focus in elderly patients with COVID-19.


Assuntos
Fatores Etários , Infecções por Coronavirus/epidemiologia , Cardiopatias/epidemiologia , Pandemias , Pneumonia Viral/epidemiologia , Síndrome do Desconforto Respiratório/epidemiologia , Injúria Renal Aguda/epidemiologia , Injúria Renal Aguda/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Betacoronavirus , COVID-19 , China/epidemiologia , Terapia Combinada , Infecções por Coronavirus/sangue , Infecções por Coronavirus/complicações , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/terapia , Cardiopatias/etiologia , Humanos , Pacientes Internados , Unidades de Terapia Intensiva/estatística & dados numéricos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Insuficiência de Múltiplos Órgãos/epidemiologia , Insuficiência de Múltiplos Órgãos/etiologia , Cuidados Paliativos/estatística & dados numéricos , Pneumonia Viral/sangue , Pneumonia Viral/complicações , Pneumonia Viral/terapia , Síndrome do Desconforto Respiratório/etiologia , Estudos Retrospectivos , SARS-CoV-2 , Centros de Atenção Terciária , Resultado do Tratamento , Adulto Jovem , Tratamento Farmacológico da COVID-19
10.
Magn Reson Chem ; 57(10): 861-872, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30746779

RESUMO

The conformational transition of a fluorinated amphiphilic dendrimer is monitored by the 1 H signal from water, alongside the 19 F signal from the dendrimer. High-field NMR data (chemical shift δ, self-diffusion coefficient D, longitudinal relaxation rate R1 , and transverse relaxation rate R2 ) for both dendrimer (19 F) and water (1 H) match each other in detecting the conformational transition. Among all parameters for both nuclei, the water proton transverse-relaxation rate R2 (1 H2 O) displays the highest relative scale of change upon conformational transition of the dendrimer. Hydrogen/deuterium-exchange mass spectrometry reveals that the compact form of the dendrimer has slower proton exchange with water than the extended form. This result suggests that the sensitivity of R2 (1 H2 O) toward dendrimer conformation originates, at least partially, from the difference in proton exchange efficiency between different dendrimer conformations. Finally, we also demonstrated that this conformational transition could be conveniently monitored using a low-field benchtop NMR spectrometer via R2 (1 H2 O). The 1 H2 O signal thus offers a simple way to monitor structural changes of macromolecules using benchtop time-domain NMR.

12.
Proc Natl Acad Sci U S A ; 112(18): 5597-601, 2015 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-25902491

RESUMO

Mechanically interlocked molecules, such as catenanes, rotaxanes, and knots, have applications in information storage, switching devices, and chemical catalysis. Rotaxanes are dumbbell-shaped molecules that are threaded through a large ring, and the relative motion of the two components along each other can respond to external stimuli. Multiple rotaxane units can amplify responsiveness, and repetitively branched molecules--dendrimers--can serve as vehicles for assembly of many rotaxanes on single, monodisperse compounds. Here, we report the synthesis of higher-generation rotaxane dendrimers by a divergent approach. Linkages were introduced as spacer elements to reduce crowding and to facilitate rotaxane motion, even at the congested periphery of the compounds up to the fourth generation. The structures were characterized by 1D multinuclear ((1)H, (13)C, and (31)P) and 2D NMR spectroscopy, MALDI-TOF-MS, gel permeation chromatography (GPC), and microscopy-based methods including atomic force microscopy (AFM) and transmission electron microscopy (TEM). AFM and TEM studies of rotaxane dendrimers vs. model dendrimers show that the rotaxane units enhance the rigidity and reduce the tendency of these assemblies to collapse by self-folding. Surface functionalization of the dendrimers with ferrocenes as termini produced electrochemically active assemblies. The preparation of dendrimers with a well-defined topological structure, enhanced rigidity, and diverse functional groups opens previously unidentified avenues for the application of these materials in molecular electronics and materials science.

15.
Proc Natl Acad Sci U S A ; 110(39): 15585-90, 2013 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-24019475

RESUMO

A powerful strategy to obtain complex supramolecular materials is the bottom-up construction of noncovalently bound materials by hierarchical self-assembly. This assembly process involves stepwise, uniform increases to the architectural complexity of a substrate, starting from discrete precursors and growing in dimensionality through controlled reactivity to a final product. Herein, two orthogonal processes are exploited: coordination-driven self-assembly and hydrogen bonding. The former relies on the predictable formation of metal-ligand bonds wherein the directionalities of the rigid precursors used determines the structural outcome. The latter uses 2-ureido-4-pyrimidinone interfaces that are structurally robust by virtue of the quadruple hydrogen bonding that can occur between subunits. By combining these two processes into a single system, it is possible to generate hierarchical materials that preserve the attractive tunability associated with discrete supramolecular coordination complexes. For instance, the synthesis of a one-dimensional chain comprising linked metalla-rhomboids is readily adapted to a 2D cross-linked hexagonal network by simply selecting a different metal acceptor precursor as an assembly component. The specific interactions between subunits, in this case platinum(II)-pyridyl bonds and the quadruple H-bonding of ureidopyrimidinone, are unchanged, establishing a unique strategy to obtain supramolecular polymers with marked topological differences with minimal synthetic redesign. In addition, the structural rigidity imposed by the inclusion of the platinum metallacycles serves to minimize the formation of cyclic oligomers, increasing the efficacy of formation and improving the properties of the resultant materials. Furthermore, this study taps the potential of organoplatinum(II) metallacycles in materials science.

16.
J Am Chem Soc ; 137(4): 1556-64, 2015 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-25574776

RESUMO

Directed by increasing the density of coordination sites (DOCS) to increase the stability of assemblies, discrete 2D ring-in-rings and 3D sphere-in-sphere were designed and self-assembled by one tetratopic pyridyl-based ligand with 180° diplatinum(II) acceptors and naked Pd(II), respectively. The high DOCS resulted by multitopic ligand provided more geometric constraints to form discrete structures with high stability. Compared to reported supramolecular hexagons and polyhedra by ditotpic ligands, the self-assembly of such giant architectures using multitopic ligands with all rigid backbone emphasized the structural integrity with precise preorganization of entire architecture, and required elaborate synthetic operations for ligand preparation. In-depth structural characterization was conducted to support desired structures, including multinuclear NMR ((1)H, (31)P, and (13)C) analysis, 2D NMR spectroscopy (COSY and NOESY), diffusion-ordered NMR spectroscopy (DOSY), multidimensional mass spectrometry, TEM and AFM. Furthermore, a quantitative definition of DOCS was proposed to compare 2D and 3D structures and correlate the DOCS and stability of assemblies in a quantitative manner. Finally, ring-in-rings in DMSO or DMF could undergo hierarchical self-assembly into the ordered nanostructures and generated translucent supramolecular metallogels.


Assuntos
Compostos Organometálicos/química , Paládio/química , Platina/química , Piridinas/química , Cristalografia por Raios X , Géis/química , Ligantes , Espectroscopia de Ressonância Magnética , Modelos Moleculares
17.
Chemistry ; 21(44): 15540-3, 2015 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-26360319

RESUMO

Palladium-catalyzed tandem reactions of 2,7-alkadiynylic carbonates with allenes bearing a carbon nucleophile such as malonate and bis(phenylsulfonyl)methane for the efficient syntheses of fused tricycles, such as 3,5,6,7-tetrahydro-1H-indeno[5,6-c]furan, 1,2,3,5,6,7-hexahydrocyclopenta[f]isoindole, and 1,2,3,5,6,7-hexahydro-s-indacene derivatives, have been reported. The reaction forms two five-membered rings and one benzene ring fusing them in the middle.

18.
Chemistry ; 21(16): 6286-94, 2015 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-25760422

RESUMO

The synthesis of discrete multirotaxanes with well-defined structures remains a great challenge. Herein, we present the successful construction of diverse discrete multirotaxanes with well-defined supramolecular metallacycles as cores by a modular approach. Moreover, these novel multirotaxanes featured a stimuli-responsive property that enabled the introduction and removal of the bromide anion by taking advantage of dynamic nature of the supramolecular metallacycle scaffold. Through the combination of rotaxane-containing prefunctionalized building blocks with the corresponding different organoplatinum(II) acceptor building blocks (60, 120, or 180°), diverse discrete multirotaxanes with well-defined metallacycles (rhomboid or hexagon) as cores as well as certain numbers of rotaxane units were successfully obtained quantitatively by means of coordination-driven self-assembly. Furthermore, owing to the existence of a dynamic metallacycle as the supramolecular cores, the resultant multirotaxanes showed anion-induced disassembly and reassembly properties, which allowed for the reversible transformation between multirotaxanes and the corresponding individual rotaxane-containing building blocks. Therefore, this research not only enriches the family of discrete multirotaxanes, but also provides a novel strategy for the construction of "smart" stimuli-responsive multirotaxane systems.

19.
Cardiology ; 130(4): 249-59, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25824726

RESUMO

OBJECTIVE: To investigate the role of ß 3 -integrin in lipopolysaccharide (LPS)-induced autophagy in cardiomyocytes and its underlying mechanism. METHODS: ß 3 -Integrin expression in cardiomyocytes was up- or downregulated by adenovirus transfection or cyclic arginine-glycine-aspartic acid (cRGD) peptide treatment before LPS stimulation. The expression of autophagy-associated proteins (LC3-II, Beclin-1 and Bcl-2) and the activation of Akt were determined using Western blotting. Autophagosomes and autophagic vacuoles were observed using monodansylcadaverine (MDC) dye and transmission electron microscopy, respectively. RESULTS: Downregulation of ß 3 -integrin with cRGD peptide resulted in enhanced LC3-II and Beclin-1 and decreased Bcl-2 expression. Low Beclin-1 levels were detected after LPS stimulation in adenovirus ß 3 -integrin-transfected cardiomyocytes. There was no significant difference in LC3-II levels between control and adenovirus ß 3 -integrin-transfected cardiomyocytes. Enhanced accumulation of MDC dye and autophagosomes, which were inhibited by ß 3 -integrin overexpression, were detected after LPS treatment. The increased phosphorylation of Akt after LPS stimulation was inhibited by cRGD and enhanced by ß 3 -integrin overexpression. Furthermore, the Akt inhibitor triciribine inhibited the negative effect of ß 3 - integrin on autophagy, as shown by LC3-II and Beclin-1 upregulation. CONCLUSIONS: ß 3 -Integrin inhibits LPS-induced autophagy in cardiomyocytes. The inhibition of Akt signaling might be an important mechanism in this process.


Assuntos
Autofagia , Integrina beta3/genética , Miócitos Cardíacos/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Apoptose , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Proteína Beclina-1 , Humanos , Lipopolissacarídeos/efeitos adversos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Microscopia Eletrônica , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Miócitos Cardíacos/ultraestrutura , Peptídeos Cíclicos/uso terapêutico , Fosforilação , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Transfecção
20.
J Am Chem Soc ; 136(24): 8577-89, 2014 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-24571308

RESUMO

A new family of discrete hexakis-pillar[5]arene metallacycles with different sizes have been successfully prepared via coordination-driven self-assembly, which presented very few successful examples of preparation of discrete multiple pillar[n]arene derivatives. These newly designed hexakis-pillar[5]arene metallacycles were well characterized with one-dimensional (1-D) multinuclear NMR ((1)H and (31) P NMR), two-dimensional (2-D) (1)H-(1)H COSY and NOESY, ESI-TOF-MS, elemental analysis, and PM6 semiempirical molecular orbital methods. Furthermore, the host-guest complexation of such hexakis-pillar[5]arene hosts with a series of different neutral ditopic guests G1-6 were well investigated. Through host-guest interactions of hexakis-pillar[5]arene metallacycles H2 or H3 with the neutral dinitrile guest G5, the cross-linked supramolecular polymers H2⊃(G5)3 or H3⊃(G5)3 were successfully constructed at the high-concentration region, respectively. Interestingly, these cross-linked supramolecular polymers transformed into the stable supramolecular gels upon increasing the concentrations to a relatively high level. More importantly, by taking advantage of the dynamic nature of metal-ligand bonds and host-guest interactions, the reversible multiple stimuli-responsive gel-sol phase transitions of such polymer gels were successfully realized under different stimuli, such as temperature, halide, and competitive guest, etc. The mechanism of such multiple stimuli-responsive processes was well illustrated by in situ multinuclear NMR investigation. This research not only provides a highly efficient approach to the preparation of discrete multiple pillar[n]arene derivatives but also presents a new family of multiple stimuli-responsive "smart" soft matters.


Assuntos
Reagentes de Ligações Cruzadas/química , Compostos Organoplatínicos/química , Polímeros/química , Compostos de Amônio Quaternário/química , Calixarenos , Reagentes de Ligações Cruzadas/síntese química , Géis/síntese química , Géis/química , Substâncias Macromoleculares/síntese química , Substâncias Macromoleculares/química , Estrutura Molecular , Compostos Organoplatínicos/síntese química , Polímeros/síntese química
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