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1.
Nanoscale ; 16(18): 9021-9028, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38629261

RESUMO

The magnetoelectric behavior of epitaxial Fe-Ga microstructures on top of a (001)-oriented PMN-PT piezoelectric substrate is imaged with magnetic X-ray microscopy. Additionally, the micron-scale strain distribution in PMN-PT is characterized by X-ray microdiffraction and examined with respect to the results of the Fe-Ga magnetoelectric switching. The magnetic reorientation of Fe-Ga is found to be strongly correlated with size, shape, and crystallographic orientation of the microstructures. In the case of square-shaped structures, size dictates the influence of the strain distribution on both the initialization of the ground state and on the magnetic reorientation during application of voltage. On the other hand, elliptical microstructures demonstrate completely different magnetic responses depending on the relative orientation of their long axis with respect to the crystallographic directions of the PMN-PT. This study demonstrates that engineering the behavior of highly magnetostrictive epitaxial microdevices is possible. It further elucidates that voltage-induced actuation can be largely tuned to achieve the desired type of magnetic switching ranging from vortex circulation reversal, domain wall motion, to a large rotation of magnetization. Because of the outstanding properties of the investigated material system, the reported findings are expected to be of great interest for the realization of next-generation energy-efficient magnetic memory and logic devices.

2.
STAR Protoc ; 5(1): 102873, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38427566

RESUMO

Here, we present a protocol to deliver nanoliter volumes of Toll-like receptor (TLR) agonist onto a culture of nuclear factor κB (NF-κB) reporter macrophages using fluidic force microscopy and a micron-scale probe. We describe steps for quantifying the dose of agonist by modeling their diffusion with experimental inputs. We then detail procedures for quantifying and categorizing macrophage responses to individual and varied doses and combining agonist concentration and macrophage response to analyze the NF-κB response to localized TLR stimulation. For complete details on the use and execution of this protocol, please refer to Mulder et al. (2024).1.


Assuntos
NF-kappa B , Receptores Toll-Like , NF-kappa B/fisiologia , Microscopia de Força Atômica , Receptor 4 Toll-Like , Macrófagos
3.
Front Immunol ; 15: 1340384, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38322261

RESUMO

The innate immune system initiates early response to infection by sensing molecular patterns of infection through pattern-recognition receptors (PRRs). Previous work on PRR stimulation of macrophages revealed significant heterogeneity in single cell responses, suggesting the importance of individual macrophage stimulation. Current methods either isolate individual macrophages or stimulate a whole culture and measure individual readouts. We probed single cell NF-κB responses to localized stimuli within a naïve culture with Fluidic Force Microscopy (FluidFM). Individual cells stimulated in naïve culture were more sensitive compared to individual cells in uniformly stimulated cultures. In cluster stimulation, NF-κB activation decreased with increased cell density or decreased stimulation time. Our results support the growing body of evidence for cell-to-cell communication in macrophage activation, and limit potential mechanisms. Such a mechanism might be manipulated to tune macrophage sensitivity, and the density-dependent modulation of sensitivity to PRR signals could have relevance to biological situations where macrophage density increases.


Assuntos
Imunidade Inata , NF-kappa B , Microscopia de Força Atômica , Macrófagos , Receptores de Reconhecimento de Padrão
5.
ACS Chem Neurosci ; 14(19): 3665-3673, 2023 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-37721710

RESUMO

Orthogonal recreation of the signaling profile of a chemical synapse is a current challenge in neuroscience. This is due in part to the kinetics of synaptic signaling, where neurotransmitters are rapidly released and quickly cleared by active reuptake machinery. One strategy to produce a rapid rise in an orthogonally controlled signal is via photocaged compounds. In this work, photocaged compounds are employed to recreate both the rapid rise and equally rapid fall in activation at a chemical synapse. Specifically, a complementary pair of photocages based on BODIPY were conjugated to a 5-HT2C subtype-selective agonist, WAY-161503, and antagonist, N-desmethylclozapine, to generate "caged" versions of these drugs. These conjugates release the bioactive drug upon illumination with green light (agonist) or red light (antagonist). We report on the synthesis, characterization, and bioactivity testing of the conjugates against the 5-HT2C receptor. We then characterize the kinetics of photolysis quantitatively using HPLC and qualitatively in cell culture conditions stimulating live cells. The compounds are shown to be stable in the dark for 48 h at room temperature, yet photolyze rapidly when irradiated with visible light. In live cells expressing the 5-HT2C receptor, precise spatiotemporal control of the degree and length of calcium signaling is demonstrated. By loading both compounds in tandem and leveraging spectral multiplexing as a noninvasive method to control local small-molecule drug availability, we can reproducibly initiate and suppress intracellular calcium flux on a timescale not possible by traditional methods of drug dosing. These tools enable a greater spatiotemporal control of 5-HT2C modulation and will allow for more detailed studies of the receptors' signaling, interactions with other proteins, and native physiology.


Assuntos
Receptor 5-HT2C de Serotonina , Serotonina , Serotonina/metabolismo , Agonistas do Receptor de Serotonina , Agonistas do Receptor 5-HT2 de Serotonina/farmacologia
6.
Cell Rep ; 41(5): 111563, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-36323246

RESUMO

Dendritic cell (DC) activation via pathogen-associated molecular patterns (PAMPs) is critical for antigen presentation and development of adaptive immune responses, but the stochastic distribution of DC responses to PAMP signaling, especially during the initial stages of immune activation, is poorly understood. In this study, we isolate a unique DC subpopulation via preferential phagocytosis of microparticles (MPs) and characterize this subpopulation of "first responders" (FRs). We present results that show these cells (1) can be isolated and studied via both increased accumulation of the micron-sized particles and combinations of cell surface markers, (2) show increased responses to PAMPs, (3) facilitate adaptive immune responses by providing the initial paracrine signaling, and (4) can be selectively targeted by vaccines to modulate both antibody and T cell responses in vivo. This study presents insights into a temporally controlled, distinctive cell population that influences downstream immune responses. Furthermore, it demonstrates potential for improving vaccine designs via FR targeting.


Assuntos
Células Dendríticas , Vacinas , Células Dendríticas/metabolismo , Moléculas com Motivos Associados a Patógenos/metabolismo , Apresentação de Antígeno , Linfócitos T
7.
ACS Chem Neurosci ; 13(20): 3008-3022, 2022 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-36183275

RESUMO

Dopaminergic pathways control highly consequential aspects of physiology and behavior. One of the most therapeutically important and best-studied receptors in these pathways is dopamine receptor D2 (DRD2). Unfortunately, DRD2 is challenging to study with traditional molecular biological techniques, and most drugs designed to target DRD2 are ligands for many other receptors. Here, we developed probes able to both covalently bind to DRD2 using photoaffinity labeling and provide a chemical handle for detection or affinity purification. These probes behaved like good DRD2 agonists in traditional biochemical assays and were able to perform in chemical-biological assays of cell and receptor labeling. Rat whole brain labeling and affinity enrichment using the probes permitted proteomic analysis of the probes' interacting proteins. Bioinformatic study of the hits revealed that the probes bound noncanonically targeted proteins in Parkinson's disease network as well as the retrograde endocannabinoid signaling, neuronal nitric oxide synthase, muscarinic acetylcholine receptor M1, GABA receptor, and dopamine receptor D1 (DRD1) signaling networks. Follow-up analysis may yield insights into how this pathway relates specifically to Parkinson's disease symptoms or provide new targets for treatments. This work reinforces the notion that the combination of chemical biology and omics-based approaches provides a broad picture of a molecule's "interactome" and may also give insight into the pleiotropy of effects observed for a drug or perhaps indicate new applications.


Assuntos
Doença de Parkinson , Receptores de Dopamina D2 , Animais , Ratos , Receptores de Dopamina D2/metabolismo , Doença de Parkinson/tratamento farmacológico , Óxido Nítrico Sintase Tipo I/metabolismo , Ligantes , Proteômica , Endocanabinoides , Receptores de Dopamina D1 , Proteínas de Transporte , Receptores de GABA/metabolismo , Agonistas de Dopamina/farmacologia
8.
Phys Rev Lett ; 126(15): 157601, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33929216

RESUMO

We construct ferroelectric (LuFeO_{3})_{m}/(LuFe_{2}O_{4}) superlattices with varying index m to study the effect of confinement on topological defects. We observe a thickness-dependent transition from neutral to charged domain walls and the emergence of fractional vortices. In thin LuFeO_{3} layers, the volume fraction of domain walls grows, lowering the symmetry from P6_{3}cm to P3c1 before reaching the nonpolar P6_{3}/mmc state, analogous to the group-subgroup sequence observed at the high-temperature ferroelectric to paraelectric transition. Our study shows how dimensional confinement stabilizes textures beyond those in bulk ferroelectric systems.

9.
Front Immunol ; 11: 511513, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33072085

RESUMO

Adjuvants are added to vaccines to enhance the immune response and provide increased protection against disease. In the last decade, hundreds of synthetic immune adjuvants have been created, but many induce undesirable levels of proinflammatory cytokines including TNF-α and IL-6. Here we present small molecule NF-κB inhibitors that can be used in combination with an immune adjuvant to both decrease markers associated with poor tolerability and improve the protective response of vaccination. Additionally, we synthesize a library of honokiol derivatives identifying several promising candidates for use in vaccine formulations.


Assuntos
Adjuvantes Imunológicos , Compostos de Bifenilo , Lignanas , NF-kappa B/antagonistas & inibidores , Adjuvantes Imunológicos/química , Adjuvantes Imunológicos/farmacologia , Animais , Compostos de Bifenilo/química , Compostos de Bifenilo/farmacologia , Lignanas/química , Lignanas/farmacologia , Camundongos , NF-kappa B/imunologia , Células RAW 264.7 , Vacinas/química , Vacinas/imunologia
10.
J Am Chem Soc ; 142(33): 14080-14089, 2020 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-32787261

RESUMO

Bioluminescence imaging with luciferase-luciferin pairs is commonly used for monitoring biological processes in cells and whole organisms. Traditional bioluminescent probes are limited in scope, though, as they cannot be easily distinguished in biological environments, precluding efforts to visualize multicellular processes. Additionally, many luciferase-luciferin pairs emit light that is poorly tissue penetrant, hindering efforts to visualize targets in deep tissues. To address these issues, we synthesized a set of π-extended luciferins that were predicted to be red-shifted luminophores. The scaffolds were designed to be rotationally labile such that they produced light only when paired with luciferases capable of enforcing planarity. A luciferin comprising an intramolecular "lock" was identified as a viable light-emitting probe. Native luciferases were unable to efficiently process the analog, but a complementary luciferase was identified via Rosetta-guided enzyme design. The unique enzyme-substrate pair is red-shifted compared to well-known bioluminescent tools. The probe set is also orthogonal to other luciferase-luciferin probes and can be used for multicomponent imaging. Four substrate-resolved luciferases were imaged in a single session. Collectively, this work provides the first example of Rosetta-guided design in engineering bioluminescent tools and expands the scope of orthogonal imaging probes.


Assuntos
Luciferina de Vaga-Lumes/química , Luciferases/química , Substâncias Luminescentes/química , Medições Luminescentes , Luciferina de Vaga-Lumes/síntese química , Luciferases/metabolismo , Luminescência , Substâncias Luminescentes/síntese química , Estrutura Molecular
11.
Adv Mater ; 32(23): e2000508, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32346899

RESUMO

Results of switching behavior of the improper ferroelectric LuFeO3 are presented. Using a model set of films prepared under controlled chemical and growth-rate conditions, it is shown that defects can reduce the quasi-static switching voltage by up to 40% in qualitative agreement with first-principles calculations. Switching studies show that the coercive field has a stronger frequency dispersion for the improper ferroelectrics compared to a proper ferroelectric such as PbTiO3 . It is concluded that the primary structural order parameter controls the switching dynamics of such improper ferroelectrics.

12.
Bioorg Med Chem ; 27(13): 2985-2990, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31128992

RESUMO

We report a study that seeks to find a correlation between the overall sensitization potential quantified by the expression of IL-8 by stimulated monocytes and the chemical structure of a model contact allergen, 2,4-dinitrochlorobenzene (DNCB). We show that structure and reactivity of the chemical compounds play an important role in activation of the monocytes and subsequent inflammation in tissue. However, we observed a non-linear correlation between the rate of reaction and biological activity indicating a required balance of stability and reactivity.


Assuntos
Alérgenos/química , Dinitroclorobenzeno/química , Estrutura Molecular
13.
Trends Biotechnol ; 37(4): 373-388, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30470547

RESUMO

Pathogens comprise a diverse set of immunostimulatory molecules that activate the innate immune system during infection. The immune system recognizes distinct combinations of pathogenic molecules leading to multiple immune activation events that cooperate to produce enhanced immune responses, known as 'immune synergies'. Effective immune synergies are essential for the clearance of pathogens, thus inspiring novel adjuvant design to improve vaccines. We highlight current vaccine adjuvants and the importance of immune synergies to adjuvant and vaccine design. The focus is on new technologies used to study and apply immune synergies to adjuvant and vaccine development. Finally, we discuss how recent findings can be applied to the future design and characterization of synergistic adjuvants and vaccines.


Assuntos
Adjuvantes Imunológicos/isolamento & purificação , Adjuvantes Imunológicos/farmacologia , Descoberta de Drogas/métodos , Vacinas/imunologia , Vacinologia/métodos , Animais , Humanos
14.
Nat Commun ; 9(1): 736, 2018 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-29467391

RESUMO

Improving the efficiency of gas separation technology is a challenge facing modern industry, since existing methods for gas separation, including hollow-fiber membrane contactors, vacuum swing adsorption, and cryogenic distillation, represents a significant portion of the world's energy consumption. Here, we report an enhancement in the release rate of carbon dioxide and oxygen of a thermal swing gas desorption unit using a counter-current amplification method inspired by fish. Differing from a conventional counter-current extraction system, counter-current amplification makes use of parallel capture fluid channels separated by a semipermeable membrane in addition to the semipermeable membrane separating the capture fluid channel and the gas release channel. The membrane separating the incoming and outgoing fluid channels allows gas that would normally exit the system to remain in the desorption unit. We demonstrate the system using both resistive heating and photothermal heating. With resistive heating, an increase in release rate of 240% was observed compared to an equivalent counter-current extraction system.

15.
ACS Appl Mater Interfaces ; 9(44): 39034-39039, 2017 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-29040810

RESUMO

Photothermal processes are utilized across a variety of fields, from separations to medicine, and are an area of active research. Herein, the action of a solar simulator upon carbon black nanoparticles is shown to result in photothermally initiated chain-growth polymerization of methyl acrylate, butyl acrylate, and methyl methacrylate initiated by benzoyl peroxide. With use of methyl acrylate as the model system, products from this reaction are shown to be apparently indistinguishable on the molecular level, but result in unique microstructures relative to the thermal controls. The relative contribution of bands of the UV/visible spectrum to the polymerization initiation show that red/infrared wavelengths are most important for the initiation to occur. Kinetic analysis of the initiator homolysis indicate that the apparent reaction rate is accelerated in the photothermal condition.

16.
ACS Biomater Sci Eng ; 3(2): 206-213, 2017 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-28936479

RESUMO

In the study of host-pathogen interactions, vaccines and drug delivery, particulate delivery system are widely used to mimic pathogen size, pattern recognition receptor agonist presentation, and target cells or organs. However, some of the polymeric systems used in particulate delivery have inherent inflammatory properties that are variable and nonspecific. These properties enhance their adjuvant activity, but confound the analysis of signaling mechanisms. Here, we present a method for particle coating with minimal background immune activation via passivation of the surface with silica-silane. We show herein that a silica-silane shell passivates polymer particles rendering them inert to activation of innate immune cells. The method is broadly applicable and can be used to coat polymeric particles of many different compositions. This method of silica-silane coating also allows conjugation of amine-bearing agonists and provides for controlled variation of agonist loading. Finally, we demonstrate our particles maintain and enhance qualities of known pathogens, making this a potentially general method for improving immune agonist activity.

17.
ACS Cent Sci ; 3(12): 1271-1275, 2017 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-29296667

RESUMO

Designing new liquids for CO2 absorption is a challenge in CO2 removal. Here, achieving low regeneration energies while keeping high selectivity and large capacity are current challenges. Recent cooperative metal-organic frameworks have shown the potential to address many of these challenges. However, many absorbent systems and designs rely on liquid capture agents. We present herein a liquid absorption system which exhibits cooperative CO2 absorption isotherms. Upon introduction, CO2 uptake is initially suppressed, followed by an abrupt increase in absorption. The liquid consists of a bifunctional guanidine and bifunctional alcohol, which, when dissolved in bis(2-methoxyethyl) ether, forms a secondary viscous phase within seconds in response to increases in CO2. The precipitation of this second viscous phase drives CO2 absorption from the gas phase. The isotherm of the bifunctional system differs starkly from the analogous monofunctional system, which exhibits limited CO2 uptake across the same pressure range. In our system, CO2 absorption is strongly solvent dependent. In DMSO, both systems exhibit hyperbolic isotherms and no precipitation occurs. Subsequent 1H NMR experiments confirmed the formation of distinct alkylcarbonate species having either one or two molecules of CO2 bound. The solvent and structure relationships derived from these results can be used to tailor new liquid absorption systems to the conditions of a given CO2 separation process.

18.
Chembiochem ; 18(1): 96-100, 2017 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-27930848

RESUMO

We report a set of brominated luciferins for bioluminescence imaging. These regioisomeric scaffolds were accessed by using a common synthetic route. All analogues produced light with firefly luciferase, although varying levels of emission were observed. Differences in photon output were analyzed by computation and photophysical measurements. The brightest brominated luciferin was further evaluated in cell and animal models. At low doses, the analogue outperformed the native substrate in cells. The remaining luciferins, although weak emitters with firefly luciferase, were inherently capable of light production and thus potential substrates for orthogonal mutant enzymes.


Assuntos
Luciferina de Vaga-Lumes/metabolismo , Medições Luminescentes , Animais , Linhagem Celular Tumoral , Vaga-Lumes/enzimologia , Luciferina de Vaga-Lumes/análogos & derivados , Luciferina de Vaga-Lumes/síntese química , Células HEK293 , Halogenação , Humanos , Cinética , Luz , Luciferases de Vaga-Lume/metabolismo , Camundongos , Camundongos Transgênicos
19.
Chemistry ; 22(11): 3671-5, 2016 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-26784889

RESUMO

Herein, the synthesis and characterization of an alkyne-modified luciferin is reported. This bioluminescent probe was accessed using C-H activation methodology and was found to be stable in solution and capable of light production with firefly luciferase. The luciferin analogue was also cell permeant and emitted more redshifted light than d-luciferin, the native luciferase substrate. Based on these features, the alkynyl luciferin will be useful for a variety of imaging applications.


Assuntos
Benzotiazóis/química , Luciferina de Vaga-Lumes/química , Luciferases de Vaga-Lume/química , Luciferases/química , Diagnóstico por Imagem , Cinética , Luciferases de Vaga-Lume/metabolismo , Medições Luminescentes
20.
J Am Chem Soc ; 134(18): 7604-7, 2012 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-22519459

RESUMO

Bioluminescence imaging with luciferase enzymes requires access to light-emitting, small-molecule luciferins. Here, we describe a rapid method to synthesize d-luciferin, the substrate for firefly luciferase (Fluc), along with a novel set of electronically modified analogues. Our procedure utilizes a relatively rare, but synthetically useful dithiazolium reagent to generate heteroaromatic scaffolds in a divergent fashion. Two of the luciferin analogues produced with this approach emit light with Fluc in vitro and in live cells. Collectively, our work increases the number of substrates that can be used for bioluminescence imaging and provides a general strategy for synthesizing new collections of luciferins.


Assuntos
Benzotiazóis/síntese química , Benzotiazóis/metabolismo , Vaga-Lumes/enzimologia , Luciferases de Vaga-Lume/metabolismo , Substâncias Luminescentes/metabolismo , Animais , Benzotiazóis/química , Células HEK293 , Humanos , Medições Luminescentes
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