Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
iScience ; 27(6): 109739, 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-39055603

RESUMO

We are a team of three battery researchers and engineers who are working with The Electrochemical Society to develop an "electrochemical techniques and diagnostics for batteries" curriculum, comprised of an online course and an in-person workshop. With a combined 40+ years of experience working in battery research and engineering, ranging from academia to electric vehicle manufacturing, we have noticed that there exists a gap in applied electrochemistry knowledge needed to train the rapidly expanding workforce of battery engineers and scientists. In this backstory, we explain the origin story of our team, our motivations for developing the course and the things we have learned in working together. We share our insights into the emerging electric vehicles business and why we believe electrochemistry education will shape the future of this industry.

2.
Nat Commun ; 12(1): 6369, 2021 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-34737263

RESUMO

The dynamic behavior of the interface between the lithium metal electrode and a solid-state electrolyte plays a critical role in all-solid-state battery performance. The evolution of this interface throughout cycling involves multiscale mechanical and chemical heterogeneity at the micro- and nano-scale. These features are dependent on operating conditions such as current density and stack pressure. Here we report the coupling of operando acoustic transmission measurements with nuclear magnetic resonance spectroscopy and magnetic resonance imaging to correlate changes in interfacial mechanics (such as contact loss and crack formation) with the growth of lithium microstructures during cell cycling. Together, the techniques reveal the chemo-mechanical behavior that governs lithium metal and Li7La3Zr2O12 interfacial dynamics at various stack pressure regimes and with voltage polarization.

3.
ChemistryOpen ; 10(5): 545-552, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33945235

RESUMO

Here, we investigate the recovery and reuse of polyvinylidene fluoride (PVDF) binders from both homemade and commercial cathode films in Li ion batteries. We find that PVDF solubility depends on whether the polymer is an isolated powder or cast into a composite film. A mixture of tetrahydrofuran:N-methyl-2-pyrrolidone (THF : NMP, 50 : 50 v/v) at 90 °C delaminates composite cathodes from Al current collectors and yields pure PVDF as characterized by 1 H nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), wide-angle X-ray scattering (WAXS), and scanning electron microscopy (SEM). PVDF recovered from Li ion cells post-cycling exhibits similar performance to pristine PVDF. These data suggest that PVDF can be extracted and reused during Li ion battery recycling while simultaneously eliminating the formation of HF etchants, providing an incentive for use in direct cathode recycling.

4.
Nano Lett ; 18(11): 7066-7074, 2018 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-30296106

RESUMO

Lithium metal is an ideal material for high-energy, cost-effective rechargeable energy storage systems. The thermodynamically unfavorable solid-liquid interface between the lithium metal and organic electrolyte necessitates the formation of an interlayer (SEI) which is known to have significant impact on lithium morphologies. Less well understood is the impact of the current collector substrate on the morphology of electrodeposited lithium. Here we report on the morphology of electrodeposited lithium as a function of the chemical pretreatments of the working electrode. We find that a copper substrate pretreatment with acidic solutions (sulfuric, oxalic, or acetic acid) results in the deposition of close-packed lithium columns with a uniform diameter. A controlled study of the pre-electrodeposited copper surface indicates that the formation of a 5-8 nm thick LiF protective layer on copper substrate from a chemical reaction between adsorbed surface water layer in acidic solutions and LiPF6 electrolyte is the key process in the electrochemical growth of lithium columns. We anticipate that this simple chemical approach can be generalized as a scalable, low-cost, additive-free substrate treatment method for depositing a LiF protective layer, broadly applicable in the development of uniform lithium films.

5.
J Immunol Methods ; 451: 20-27, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28803843

RESUMO

With current available assay formats using either immobilized protein (ELISA, enzyme-linked immunosorbent assay) or immunostaining of fixed cells for primary monoclonal antibody (mAb) screening, researchers often fail to identify and characterize antibodies that recognize the native conformation of cell-surface antigens. Therefore, screening using live cells has become an integral and important step contributing to the successful identification of therapeutic antibody candidates. Thus the need for developing high-throughput screening (HTS) technologies using live cells has become a major priority for therapeutic mAb discovery and development. We have developed a novel technique called Multiplexed Fluorescent Cell Barcoding (MFCB), a flow cytometry-based method based upon the Fluorescent Cell Barcoding (FCB) technique and the Luminex fluorescent bead array system, but is applicable to high-through mAb screens on live cells. Using this technique in our system, we can simultaneously identify or characterize the antibody-antigen binding of up to nine unique fluorescent labeled cell populations in the time that it would normally take to process a single population. This has significantly reduced the amount of time needed for the identification of potential lead candidates. This new technology enables investigators to conduct large-scale primary hybridoma screens using flow cytometry. This in turn has allowed us to screen antibodies more efficiently than before and streamline identification and characterization of lead molecules.


Assuntos
Anticorpos Monoclonais/metabolismo , Antígenos de Superfície/imunologia , Separação Celular/métodos , Citometria de Fluxo/métodos , Corantes Fluorescentes/química , Ensaios de Triagem em Larga Escala/métodos , Hibridomas/metabolismo , Animais , Anticorpos Monoclonais/biossíntese , Anticorpos Monoclonais/imunologia , Formação de Anticorpos , Especificidade de Anticorpos , Antígenos de Superfície/genética , Sítios de Ligação de Anticorpos , Células CHO , Cricetulus , Feminino , Células HEK293 , Humanos , Hibridomas/imunologia , Camundongos Endogâmicos C57BL , Valor Preditivo dos Testes , Ligação Proteica , Reprodutibilidade dos Testes , Transfecção
6.
Biochem Mol Biol Educ ; 44(4): 326-35, 2016 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-26923186

RESUMO

Understanding how basic structural units influence function is identified as a foundational/core concept for undergraduate biological and biochemical literacy. It is essential for students to understand this concept at all size scales, but it is often more difficult for students to understand structure-function relationships at the molecular level, which they cannot as effectively visualize. Students need to develop accurate, 3-dimensional mental models of biomolecules to understand how biomolecular structure affects cellular functions at the molecular level, yet most traditional curricular tools such as textbooks include only 2-dimensional representations. We used a controlled, backward design approach to investigate how hand-held physical molecular model use affected students' ability to logically predict structure-function relationships. Brief (one class period) physical model use increased quiz score for females, whereas there was no significant increase in score for males using physical models. Females also self-reported higher learning gains in their understanding of context-specific protein function. Gender differences in spatial visualization may explain the gender-specific benefits of physical model use observed. © 2016 The Authors Biochemistry and Molecular Biology Education published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology, 44(4):326-335, 2016.


Assuntos
Bioquímica/educação , Compreensão , Aprendizagem , Proteínas Associadas aos Microtúbulos/química , Antígenos de Histocompatibilidade Menor/química , Modelos Anatômicos , Reconhecimento Psicológico , Estudantes/psicologia , Gráficos por Computador , Feminino , Humanos , Imageamento Tridimensional , Masculino , Estrutura Secundária de Proteína , Relação Estrutura-Atividade
7.
Cancer Res ; 75(24): 5329-40, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26631267

RESUMO

Antibody-drug conjugates (ADC) target cytotoxic drugs to antigen-positive cells for treating cancer. After internalization, ADCs with noncleavable linkers are catabolized to amino acid-linker-warheads within the lysosome, which then enter the cytoplasm by an unknown mechanism. We hypothesized that a lysosomal transporter was responsible for delivering noncleavable ADC catabolites into the cytoplasm. To identify candidate transporters, we performed a phenotypic shRNA screen with an anti-CD70 maytansine-based ADC. This screen revealed the lysosomal membrane protein SLC46A3, the genetic attenuation of which inhibited the potency of multiple noncleavable antibody-maytansine ADCs, including ado-trastuzumab emtansine. In contrast, the potencies of noncleavable ADCs carrying the structurally distinct monomethyl auristatin F were unaffected by SLC46A3 attenuation. Structure-activity experiments suggested that maytansine is a substrate for SLC46A3. Notably, SLC46A3 silencing led to relative increases in catabolite concentrations in the lysosome. Taken together, our results establish SLC46A3 as a direct transporter of maytansine-based catabolites from the lysosome to the cytoplasm, prompting further investigation of SLC46A3 as a predictive response marker in breast cancer specimens.


Assuntos
Antineoplásicos Fitogênicos/metabolismo , Imunoconjugados/metabolismo , Maitansina/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Antineoplásicos Fitogênicos/administração & dosagem , Linhagem Celular Tumoral , Citoplasma/metabolismo , Sistemas de Liberação de Medicamentos , Humanos , Imunoconjugados/administração & dosagem , Lisossomos/metabolismo , Maitansina/administração & dosagem
8.
Mol Cancer Ther ; 14(7): 1614-24, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25931519

RESUMO

Epidermal growth factor receptor variant III (EGFRvIII) is a cancer-specific deletion mutant observed in approximately 25% to 50% of glioblastoma multiforme (GBM) patients. An antibody drug conjugate, AMG 595, composed of the maytansinoid DM1 attached to a highly selective anti-EGFRvIII antibody via a noncleavable linker, was developed to treat EGFRvIII-positive GBM patients. AMG 595 binds to the cell surface and internalizes into the endo-lysosomal pathway of EGFRvIII-expressing cells. Incubation of AMG 595 with U251 cells expressing EGFRvIII led to potent growth inhibition. AMG 595 treatment induced significant tumor mitotic arrest, as measured by phospho-histone H3, in GBM subcutaneous xenografts expressing EGFRvIII. A single intravenous injection of AMG 595 at 17 mg/kg (250 µg DM1/kg) generated complete tumor regression in the U251vIII subcutaneous xenograft model. AMG 595 mediated tumor regression in the D317 subcutaneous xenograft model that endogenously expresses EGFRvIII. Finally, AMG 595 treatment inhibited the growth of D317 xenografts orthotopically implanted into the brain as determined by magnetic resonance imaging. These results demonstrate that AMG 595 is a promising candidate to evaluate in EGFRvIII-expressing GBM patients.


Assuntos
Anticorpos Monoclonais/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Receptores ErbB/imunologia , Glioblastoma/tratamento farmacológico , Imunoconjugados/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/imunologia , Neoplasias Encefálicas/imunologia , Neoplasias Encefálicas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Receptores ErbB/genética , Receptores ErbB/metabolismo , Feminino , Glioblastoma/imunologia , Glioblastoma/metabolismo , Humanos , Imunoconjugados/administração & dosagem , Imunoconjugados/imunologia , Imuno-Histoquímica , Injeções Intravenosas , Maitansina/análogos & derivados , Maitansina/imunologia , Maitansina/farmacologia , Camundongos Nus , Camundongos SCID , Mutação , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Resultado do Tratamento , Carga Tumoral/efeitos dos fármacos , Carga Tumoral/imunologia
9.
Cancer Cell ; 26(2): 177-89, 2014 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-25043603

RESUMO

Death receptor agonist therapies have exhibited limited clinical benefit to date. Investigations into why Apo2L/TRAIL and AMG 655 preclinical data were not predictive of clinical response revealed that coadministration of Apo2L/TRAIL with AMG 655 leads to increased antitumor activity in vitro and in vivo. The combination of Apo2L/TRAIL and AMG 655 results in enhanced signaling and can sensitize Apo2L/TRAIL-resistant cells. Structure determination of the Apo2L/TRAIL-DR5-AMG 655 ternary complex illustrates how higher order clustering of DR5 is achieved when both agents are combined. Enhanced agonism generated by combining Apo2L/TRAIL and AMG 655 provides insight into the limited efficacy observed in previous clinical trials and suggests testable hypotheses to reconsider death receptor agonism as a therapeutic strategy.


Assuntos
Anticorpos Monoclonais/farmacologia , Antineoplásicos/farmacologia , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Animais , Anticorpos Monoclonais/química , Antineoplásicos/química , Linhagem Celular Tumoral , Sobrevivência Celular , Cristalografia por Raios X , Resistencia a Medicamentos Antineoplásicos , Sinergismo Farmacológico , Humanos , Camundongos , Modelos Moleculares , Multimerização Proteica , Estrutura Quaternária de Proteína , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/antagonistas & inibidores , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/química , Transdução de Sinais , Ligante Indutor de Apoptose Relacionado a TNF/química , Ensaios Antitumorais Modelo de Xenoenxerto
10.
J Am Chem Soc ; 134(38): 15849-57, 2012 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-22957510

RESUMO

Electrocatalyst for oxygen reduction reaction (ORR) is crucial for a variety of renewable energy applications and energy-intensive industries. The design and synthesis of highly active ORR catalysts with strong durability at low cost is extremely desirable but remains challenging. Here, we used a simple two-step method to synthesize cobalt oxide/carbon nanotube (CNT) strongly coupled hybrid as efficient ORR catalyst by directly growing nanocrystals on oxidized multiwalled CNTs. The mildly oxidized CNTs provided functional groups on the outer walls to nucleate and anchor nanocrystals, while retaining intact inner walls for highly conducting network. Cobalt oxide was in the form of CoO due to a gas-phase annealing step in NH(3). The resulting CoO/nitrogen-doped CNT (NCNT) hybrid showed high ORR current density that outperformed Co(3)O(4)/graphene hybrid and commercial Pt/C catalyst at medium overpotential, mainly through a 4e reduction pathway. The metal oxide/carbon nanotube hybrid was found to be advantageous over the graphene counterpart in terms of active sites and charge transport. Last, the CoO/NCNT hybrid showed high ORR activity and stability under a highly corrosive condition of 10 M NaOH at 80 °C, demonstrating the potential of strongly coupled inorganic/nanocarbon hybrid as a novel catalyst system in oxygen depolarized cathode for chlor-alkali electrolysis.


Assuntos
Cobalto/química , Nanopartículas , Nanotubos de Carbono , Óxidos/química , Oxigênio/química , Catálise , Técnicas Eletroquímicas , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão
11.
Nat Commun ; 3: 917, 2012 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-22735445

RESUMO

Ultrafast rechargeable batteries made from low-cost and abundant electrode materials operating in safe aqueous electrolytes could be attractive for electrochemical energy storage. If both high specific power and energy are achieved, such batteries would be useful for power quality applications such as to assist propelling electric vehicles that require fast acceleration and intense braking. Here we develop a new type of Ni-Fe battery by employing novel inorganic nanoparticle/graphitic nanocarbon (carbon nanotubes and graphene) hybrid materials as electrode materials. We successfully increase the charging and discharging rates by nearly 1,000-fold over traditional Ni-Fe batteries while attaining high energy density. The ultrafast Ni-Fe battery can be charged in ~2 min and discharged within 30 s to deliver a specific energy of 120 Wh kg(-1) and a specific power of 15 kW kg(-1). These features suggest a new generation of Ni-Fe batteries as novel devices for electrochemical energy storage.


Assuntos
Fontes de Energia Elétrica , Ferro/química , Nanotecnologia/instrumentação , Níquel/química , Nanopartículas/química , Nanotubos de Carbono/química
12.
Artigo em Inglês | MEDLINE | ID: mdl-20101712

RESUMO

Injury to the nervous system is a common occurrence after trauma. Severe cases of injury exact a tremendous personal cost and place a significant healthcare burden on society. Unlike some tissues in the body that exhibit self healing, nerve cells that are injured, particularly those in the brain and spinal cord, are incapable of regenerating circuits by themselves to restore neurological function. In recent years, researchers have begun to explore whether micro/nanoscale tools and materials can be used to address this major challenge in neuromedicine. Efforts in this area have proceeded along two lines. One is the development of new nanoscale tissue scaffold materials to act as conduits and stimulate axon regeneration. The other is the use of novel cellular-scale surgical micro/nanodevices designed to perform surgical microsplicing and the functional repair of severed axons. We discuss results generated by these two approaches and hurdles confronting both strategies.


Assuntos
Axônios/patologia , Nanotecnologia/métodos , Procedimentos de Cirurgia Plástica , Cicatrização , Animais , Regeneração Tecidual Guiada , Humanos , Alicerces Teciduais/química
13.
Neurosurgery ; 65(4 Suppl): A52-4, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19927078

RESUMO

OBJECTIVE: Our goal is to develop a novel method to repair damaged axons. This method relies on acutely restoring axonal continuity rather than the traditional approach of promoting axonal regeneration. METHODS: Micro- and nanoechnological methods, in combination with focal application of electrical fields, are applied to individual and groups of axons both in vitro and in vivo. RESULTS: Application of these techniques has permitted micromanipulation of axons at the cellular level and fusion of axonal membranes. CONCLUSION: Although a great deal more work is necessary, our findings suggest that it may one day be possible to repair acutely disrupted axons by splicing their membranes back together.


Assuntos
Regeneração Nervosa/fisiologia , Procedimentos Neurocirúrgicos/métodos , Nervos Periféricos/cirurgia , Doenças do Sistema Nervoso Periférico/cirurgia , Axônios/fisiologia , Axônios/efeitos da radiação , Axônios/ultraestrutura , Membrana Celular/fisiologia , Membrana Celular/ultraestrutura , Terapia por Estimulação Elétrica/métodos , Campos Eletromagnéticos , Humanos , Microcirurgia/métodos , Nanotecnologia/métodos , Nanotecnologia/tendências , Regeneração Nervosa/efeitos da radiação , Nervos Periféricos/patologia , Nervos Periféricos/fisiopatologia , Doenças do Sistema Nervoso Periférico/patologia , Doenças do Sistema Nervoso Periférico/fisiopatologia , Recuperação de Função Fisiológica/fisiologia , Recuperação de Função Fisiológica/efeitos da radiação
14.
Biosens Bioelectron ; 24(12): 3600-7, 2009 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-19535240

RESUMO

As biomedical research has moved increasingly towards experimentation on single cells and subcellular structures, there has been a need for microscale devices that can perform manipulation and stimulation at a correspondingly small scale. We propose a microelectrode array (MEA) featuring thickened microelectrodes with vertical sidewalls (VSW) to focus electrical fields horizontally on targets positioned in between paired electrodes. These microelectrodes were fabricated using gold electroplating that was molded by photolithographically patterned SU-8 photoresist. Finite element modeling showed that paired VSW electrodes produce more uniform electrical fields compared to conventional planar microelectrodes. Using paired microelectrodes, 3 microm thick and spaced 10 microm apart, we were able to perform local electroporation of individual axonal processes, as demonstrated by entry of EGTA to locally chelate intra-axonal calcium, quenching the fluorescence of a pre-loaded calcium indicator dye. The same electrode configuration was used to electroporate individual cells, resulting in the targeted transfection of a transgene expressing a cytoplasmically soluble green fluorescent protein (GFP). In addition to electroporation, our electrode configuration was also capable of precisely targeted field stimulation on individual neurons, resulting in action potentials that could be tracked by optical means. With its ability to deliver well-characterized electrical fields and its versatility, our configuration of paired VSW electrodes may provide the basis for a new tool for high-throughput and high-content experimentation in broad areas of neuroscience and biomedical research.


Assuntos
Separação Celular/instrumentação , Estimulação Elétrica/instrumentação , Eletroporação/instrumentação , Microeletrodos , Micromanipulação/instrumentação , Neurônios/fisiologia , Neurônios/efeitos da radiação , Animais , Células Cultivadas , Campos Eletromagnéticos , Desenho de Equipamento , Análise de Falha de Equipamento , Camundongos
15.
Cancer Res ; 69(6): 2358-64, 2009 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-19258515

RESUMO

Antibody-drug conjugates (ADC), potent cytotoxic drugs covalently linked to antibodies via chemical linkers, provide a means to increase the effectiveness of chemotherapy by targeting the drug to neoplastic cells while reducing side effects. Here, we systematically examine the potential targets and linker-drug combinations that could provide an optimal ADC for the treatment for non-Hodgkin's lymphoma. We identified seven antigens (CD19, CD20, CD21, CD22, CD72, CD79b, and CD180) for potential treatment of non-Hodgkin's lymphoma with ADCs. ADCs with cleavable linkers mediated in vivo efficacy via all these targets; ADCs with uncleavable linkers were only effective when targeted to CD22 and CD79b. In target-independent safety studies in rats, the uncleavable linker ADCs showed reduced toxicity, presumably due to the reduced release of free drug or other toxic metabolites into the circulation. Thus, our data suggest that ADCs with cleavable linkers work on a broad range of targets, and for specific targets, ADCs with uncleavable linkers provide a promising opportunity to improve the therapeutic window for ADCs in humans.


Assuntos
Antineoplásicos/administração & dosagem , Imunotoxinas/farmacologia , Linfoma não Hodgkin/tratamento farmacológico , Maitansina/análogos & derivados , Oligopeptídeos/administração & dosagem , Compostos de Sulfidrila/administração & dosagem , Animais , Antígenos CD/biossíntese , Antígenos CD/imunologia , Antineoplásicos/farmacocinética , Linfócitos B/imunologia , Reagentes de Ligações Cruzadas/administração & dosagem , Reagentes de Ligações Cruzadas/farmacocinética , Feminino , Imunotoxinas/imunologia , Imunotoxinas/farmacocinética , Linfoma não Hodgkin/imunologia , Maitansina/administração & dosagem , Maitansina/farmacocinética , Camundongos , Camundongos Endogâmicos ICR , Camundongos SCID , Oligopeptídeos/farmacocinética , Ratos , Compostos de Sulfidrila/farmacocinética , Ensaios Antitumorais Modelo de Xenoenxerto
16.
Neurol Res ; 30(10): 1053-62, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19079980

RESUMO

OBJECTIVE: This review will describe the novel contributions to the field of nerve repair from the emerging disciplines of microtechnology and nanotechnology. METHOD: This broad review will cover the advances described in the literature of the medical and biological fields and the engineering and physical sciences. The authors have also included their own work in this field. DISCUSSION: Microtechnology and nanotechnology are providing two fundamentally different pathways for pursuing nerve repair: (1) microstructured scaffolds to promote regeneration and (2) direct repair by reconnecting axons. In the first instance, many of the traditional techniques for microfabrication of microelectronics have been applied to the development of implantable tissue scaffolds with precisely formed architectures. Combined with nanotechnological capabilities to control their surface chemistries, these tissue constructs have been designed to create a microenvironment within nerve tissue to optimally promote the outgrowth of neurites. With some initial successes in animal models, these next generation tissue scaffolds may provide a marked improvement over traditional nerve grafts in the ability to overcome nerve degenerative processes and to coax nerve regeneration leading to restoration of at least some nerve function. A second, completely different repair strategy aims to directly repair nerves at the microscale by acutely reconnecting severed or damaged axons immediately after injury and potentially forestalling the usual downstream degenerative processes. This strategy will take advantage of the traditional capabilities of microfabrication to create microelectromechanical systems that will serve as ultramicrosurgical tools that can operate at the micron scale and reliably manipulate individual axons without incurring damage. To bring about some restoration of a nerve's function, axon repair will have to be performed repetitively on a large scale and soon after injury. Development work is currently underway to bring about the feasibility of this technique. CONCLUSION: With the emergence of microtechnology and nanotechnology, new methods for repairing nerves are being explored and developed. There have been two fundamental benefits from the technologies of the ultrasmall scale: (1) enhancement of regeneration using new tissue scaffold materials and architecture; (2) direct repair of nerves at the scale of single neurons and axons.


Assuntos
Microtecnologia/métodos , Nanotecnologia/métodos , Regeneração Nervosa/fisiologia , Doenças do Sistema Nervoso Periférico/terapia , Engenharia Tecidual/métodos , Animais , Humanos
17.
Langmuir ; 24(22): 13048-57, 2008 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-18925765

RESUMO

The ability to organize individual neurons and their processes in culture provides important benefits to both basic neuroscience research applications and the development of biomedical microdevices. While numerous methods have been used to produce such micropatterning of neurons and cells in general, there has yet been no method to simultaneously provide high-resolution patterns with high compliance of cells to desired patterns and good manufacturability. To develop such a process, this work used a plasma polymerized, nonfouling poly ethylene oxide (PEO)-like film to provide a cell repellant substrate on which cell adhesive micropatterns can be selectively laid down. While the use of plasma polymerized, organic films have been used for cell micropatterning, this process exploits the often-overlooked tendency for the surface of this PEO-like material to adsorb polylysine from aqueous solution while remaining nonfouling with respect to other species, such as bovine serum albumin (BSA) and immunoglobulin G (IgG). When the adsorption of polylysine was enhanced by brief plasma oxidation, which slightly alters the surface chemistry of the material, simple photolithographic liftoff could be used to micropattern stable, cell adhesive areas on an otherwise cell repellant background. We showed that the application of photolithography itself on the PEO-like material did not alter its chemical properties, nor did it result in the erosion of the micropatterned polylysine on its surface. Hippocampal neurons from embryonic mice flourished on these micropatterned substrates and exhibited viability comparable to neurons cultured on polylysine coated glass. Furthermore, the compliance of cell bodies and outgrowing neurites to the micropatterns was nearly perfect. In addition to providing cell adhesive regions, the micropatterned polylysine coating also served as a template mediating the immobilization of other bioactive species such as IgG and laminin. Using this "piggybacking" of laminin on polylysine, we were also able to culture and micropattern retinal ganglion cells (RGC).


Assuntos
Técnicas de Cultura de Células/instrumentação , Neurônios/metabolismo , Polilisina/química , Adsorção , Animais , Adesão Celular , Técnicas de Cultura de Células/métodos , Hipocampo/embriologia , Imunoglobulina G/química , Laminina/química , Camundongos , Microscopia de Força Atômica , Oxigênio/química , Polietilenoglicóis/química , Polímeros/química , Células Ganglionares da Retina/metabolismo
18.
Br J Haematol ; 140(1): 46-58, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17991300

RESUMO

CD19 and CD21 (CR2) are co-receptors found on B-cells and various B-cell lymphomas, including non-Hodgkin lymphoma. To evaluate their suitability as targets for therapy of such lymphomas using internalization-dependent antibody-drug conjugates [such as antibody-4-(N-maleimidomethyl)cyclohexane-1-carboxylate, (N2'-deacetyl-N2'-(3-mercapto-1-oxopropyl)-maytansine) (MCC-DM1) conjugates, which require lysosomal degradation of the antibody moiety for efficacy], we examined uptake of antibodies to CD19 and CD21 in a panel of B-cell lines. Anti-CD21 antibodies were not sufficiently internalized even in the highest CD21-expressing Raji cells, resulting in lack of efficacy with anti-CD21-MCC-DM1 conjugates. Anti-CD19 antibody uptake was variable, and was unexpectedly negatively correlated with CD21 expression. Thus, high CD21-expressing Raji, ARH77 and primary B-cells only very slowly internalized anti-CD19 antibodies, while CD21-negative or low expressing cells, including Ramos and Daudi, rapidly internalized these antibodies in clathrin-coated vesicles followed by lysosomal delivery. Anti-CD19-MCC-DM1 caused greater cytotoxicity in the faster anti-CD19-internalizing cell lines, implying that the rate of lysosomal delivery and subsequent drug release is important. Furthermore, transfection of Ramos cells with CD21 impeded anti-CD19 uptake and decreased anti-CD19-MCC-DM1 efficacy, suggesting that CD21-negative tumours should respond better to such anti-CD19 conjugates. This may have possible clinical implications, as anti-CD21 immunohistochemistry revealed only approximately 30% of 54 diffuse large B-cell lymphoma patients lack CD21 expression.


Assuntos
Anticorpos Antineoplásicos/imunologia , Antígenos CD19/imunologia , Imunoconjugados/uso terapêutico , Linfoma de Células B/terapia , Receptores de Complemento 3d/metabolismo , Apoptose/imunologia , Linhagem Celular Tumoral , Clatrina/farmacologia , Citotoxicidade Imunológica/imunologia , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Linfoma de Células B/imunologia
19.
Neurosurgery ; 61(4): 683-91; discussion 691-2, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17986929

RESUMO

OBJECTIVE: Microfabricated devices with nanoscale features have been proposed as new microinstrumentation for cellular and subcellular surgical procedures, but their effectiveness in vivo has yet to be demonstrated. In this study, we examined the in vivo use of 10 to 100 microm-long nanoknives with cutting edges of 20 nm in radius of curvature during peripheral nerve surgery. METHODS: Peripheral nerves from anesthetized mice were isolated on a rudimentary microplatform with stimulation microelectrodes, and the nanoknives were positioned by a standard micromanipulator. The surgical field was viewed through a research microscope system with brightfield and fluorescence capabilities. RESULTS: Using this assembly, the nanoknife effectively made small, 50 to 100 microm-long incisions in nerve tissue in vivo. This microfabricated device was also robust enough to make repeated incisions to progressively pare down the nerve as documented visually and by the accompanying incremental diminution of evoked motor responses recorded from target muscle. Furthermore, this nanoknife also enabled the surgeon to perform procedures at an unprecedented small scale such as the cutting and isolation of a small segment from a single constituent axon in a peripheral nerve in vivo. Lastly, the nanoknife material (silicon nitride) did not elicit any acute neurotoxicity as evidenced by the robust growth of axons and neurons on this material in vitro. CONCLUSION: Together, these demonstrations support the concept that microdevices deployed in a neurosurgical environment in vivo can enable novel procedures at an unprecedented small scale. These devices are potentially the vanguard of a new family of microscale instrumentation that can extend surgical procedures down to the cellular scale and beyond.


Assuntos
Axônios , Microcirurgia/instrumentação , Nanotecnologia/instrumentação , Animais , Axônios/fisiologia , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microcirurgia/métodos , Nanotecnologia/métodos
20.
Blood ; 110(2): 616-23, 2007 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-17374736

RESUMO

Targeting cytotoxic drugs to cancer cells using antibody-drug conjugates (ADCs), particularly those with stable linkers between the drug and the antibody, could be an effective cancer treatment with low toxicity. However, for stable-linker ADCs to be effective, they must be internalized and degraded, limiting potential targets to surface antigens that are trafficked to lysosomes. CD79a and CD79b comprise the hetrodimeric signaling component of the B-cell receptor, and are attractive targets for the use of ADCs because they are B-cell-specific, expressed in non-Hodgkin lymphomas (NHL), and are trafficked to a lysosomal-like compartment as part of antigen presentation. We show here that the stable-linker ADCs anti-CD79b-MCC-DM1 and anti-CD79b-MC-MMAF are capable of target-dependent killing of nonHodgkin lymphoma cell lines in vitro. Further, these 2 ADCs are equally effective as low doses in xenograft models of follicular, mantle cell, and Burkitt lymphomas, even though several of these cell lines express relatively low levels of CD79b in vivo. In addition, we demonstrate that anti-CD79b ADCs were more effective than anti-CD79a ADCs and that, as hypothesized, anti-CD79b antibodies downregulated surface B-cell receptor and were trafficked to the lysosomal-like major histocompatibility complex class II-positive compartment MIIC. These results suggest that anti-CD79b-MCC-DM1 and anti-CD79b-MC-MMAF are promising therapeutics for the treatment of NHL.


Assuntos
Anticorpos/uso terapêutico , Antígenos CD79/imunologia , Imunoconjugados/uso terapêutico , Linfoma não Hodgkin/imunologia , Animais , Células CHO , Linhagem Celular Tumoral , Cricetinae , Cricetulus , Feminino , Citometria de Fluxo , Antígenos HLA-D/imunologia , Humanos , Lisossomos/imunologia , Camundongos , Camundongos SCID , Receptores de Antígenos de Linfócitos B/imunologia , Transplante Heterólogo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA