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1.
Nat Methods ; 18(11): 1294-1303, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34725485

RESUMEN

Spheroids are three-dimensional cellular models with widespread basic and translational application across academia and industry. However, methodological transparency and guidelines for spheroid research have not yet been established. The MISpheroID Consortium developed a crowdsourcing knowledgebase that assembles the experimental parameters of 3,058 published spheroid-related experiments. Interrogation of this knowledgebase identified heterogeneity in the methodological setup of spheroids. Empirical evaluation and interlaboratory validation of selected variations in spheroid methodology revealed diverse impacts on spheroid metrics. To facilitate interpretation, stimulate transparency and increase awareness, the Consortium defines the MISpheroID string, a minimum set of experimental parameters required to report spheroid research. Thus, MISpheroID combines a valuable resource and a tool for three-dimensional cellular models to mine experimental parameters and to improve reproducibility.


Asunto(s)
Biomarcadores de Tumor/genética , Proliferación Celular , Bases del Conocimiento , Neoplasias/patología , Programas Informáticos , Esferoides Celulares/patología , Microambiente Tumoral , Técnicas de Cultivo de Célula/métodos , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias/clasificación , Neoplasias/metabolismo , RNA-Seq , Reproducibilidad de los Resultados , Esferoides Celulares/inmunología , Esferoides Celulares/metabolismo , Células Tumorales Cultivadas
2.
Int J Mol Sci ; 24(4)2023 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-36834634

RESUMEN

This study analyzed the nuclease- and serum-driven degradation of millimeter-scale, circular DNA-histone mesostructures (DHMs). DHMs are bioengineered chromatin meshes of defined DNA and histone compositions designed as minimal mimetics of physiological extracellular chromatin structures, such as neutrophil extracellular traps (NETs). Taking advantage of the defined circular shape of the DHMs, an automated time-lapse imaging and image analysis method was developed and used to track DHM degradation and shape changes over time. DHMs were degraded well by 10 U/mL concentrations of deoxyribonuclease I (DNase I) but not by the same level of micrococcal nuclease (MNase), whereas NETs were degraded well by both nucleases. These comparative observations suggest that DHMs have a less accessible chromatin structure compared to NETs. DHMs were degraded by normal human serum, although at a slower rate than NETs. Interestingly, time-lapse images of DHMs revealed qualitative differences in the serum-mediated degradation process compared to that mediated by DNase I. Importantly, despite their reduced susceptibility to degradation and compositional simplicity, the DHMs mimicked NETs in being degraded to a greater extent by normal donor serum compared to serum from a lupus patient with high disease activity. These methods and insights are envisioned to guide the future development and expanded use of DHMs, beyond the previously reported antibacterial and immunostimulatory analyses, to extracellular chromatin-related pathophysiological and diagnostic studies.


Asunto(s)
Cromatina , Trampas Extracelulares , Humanos , Cromatina/metabolismo , Histonas/metabolismo , Neutrófilos/metabolismo , Trampas Extracelulares/metabolismo , ADN/metabolismo , Desoxirribonucleasa I/metabolismo
3.
J Chem Eng Data ; 67(8): 1964-1971, 2022 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-38046220

RESUMEN

The phase separation of aqueous polymer solutions is a widely used method for producing self-assembled, membraneless droplet protocells. Non-ionic synthetic polymers forming an aqueous two-phase system (ATPS) have been shown to reliably form protocells that, when equipped with biological materials, are useful for applications such as analyte detection. Previous characterization of an ATPS-templated protocell did not investigate the effects of its biological components on phase stability. Here we report the phase diagram of a PEG 35k-Ficoll 400k-water ATPS at baseline and in the presence of necessary protocell components. Because the stability of an ATPS can be sensitive to small changes in composition, which in turn impacts solute partitioning, we present partitioning data of a variety of nucleic acids in response to protocell additives. The results show that the additives-particularly a mixture of salts and small organic molecules-have profound positive effects on ATPS stability and nucleic acid partitioning, both of which significantly contribute to protocell function. Our data uncovers several new areas of optimization for future protocell engineering.

4.
Analyst ; 145(10): 3517-3527, 2020 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-32248215

RESUMEN

This work describes a convenient one-hour enzyme-linked immunosorbent assay (ELISA) formulated with conventional antibodies and horseradish peroxidase (HRP) reagents. The method utilizes aqueous two-phase system (ATPS) droplet formation based on poly(ethylene glycol) (PEG)-containing sample solution-triggered rehydration of dehydrated dextran (DEX) spots that contain all antibody reagents. Key advances in this paper include development of a formulation that allows a quick 1-hour overall incubation time and a procedure where inclusion of the HRP reagent in the PEG solution reduces the number of washing and incubation steps required to perform this assay. As an assay application, a 5-plex cytokine test compares cytokine secretion of differentially-treated human ThP-1 macrophages. Given the use of only readily available reagents and a common Western blot imaging system for the readout, this method is envisioned to be broadly applicable to a variety of multiplex immunoassays. To facilitate broader use, companion image processing software as an ImageJ plugin is also described and provided.


Asunto(s)
Ensayo de Inmunoadsorción Enzimática/métodos , Agua/química , Línea Celular , Dextranos/química , Peroxidasa de Rábano Silvestre/metabolismo , Humanos , Polietilenglicoles/química , Factores de Tiempo
5.
Biophys J ; 116(5): 962-973, 2019 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-30782397

RESUMEN

Mammalian cells respond in a variable manner when provided with physiological pulses of ligand, such as low concentrations of acetylcholine present for just tens of seconds or TNFα for just tens of minutes. For a two-pulse stimulation, some cells respond to both pulses, some do not respond, and yet others respond to only one or the other pulse. Are these different response patterns the result of the small number of ligands being able to only stochastically activate the pathway at random times or an output pattern from a deterministic algorithm responding differently to different stimulation intervals? If the response is deterministic in nature, what parameters determine whether a response is generated or skipped? To answer these questions, we developed a two-pulse test that utilizes different rest periods between stimulation pulses. This "rest-period test" revealed that cells skip responses predictably as the rest period is shortened. By combining these experimental results with a mathematical model of the pathway, we further obtained mechanistic insight into potential sources of response variability. Our analysis indicates that in both intracellular calcium and NFκB signaling, response variability is consistent with extrinsic noise (cell-to-cell variability in protein levels), a short-term memory of stimulation, and high Hill coefficient processes. Furthermore, these results support recent works that have emphasized the role of deterministic processes for explaining apparently stochastic cellular response variability and indicate that even weak stimulations likely guide mammalian cells to appropriate fates rather than leaving outcomes to chance. We envision that the rest-period test can be applied to other signaling pathways to extract mechanistic insight.


Asunto(s)
Estimulación Eléctrica , Transducción de Señal , Calcio/metabolismo , Células HEK293 , Humanos , Cinética , Dispositivos Laboratorio en un Chip , Modelos Biológicos , FN-kappa B/metabolismo , Procesos Estocásticos , Factor de Necrosis Tumoral alfa/metabolismo
6.
Chembiochem ; 20(2): 270-275, 2019 01 18.
Artículo en Inglés | MEDLINE | ID: mdl-30394637

RESUMEN

Handling the aqueous two-phase systems (ATPSs) formed by liquid-liquid phase separation (LLPS) relies on the accurate construction of binodal curves and tie-lines, which delineate the polymer concentrations required for phase separation and depict the properties of the resulting phases, respectively. Various techniques to determine the binodal curves and tie-lines of ATPSs exist, but most rely on manually pipetting relatively large volumes of fluids in a slow and tedious manner. We describe a method to determine ATPS binodals and tie-lines that overcomes these disadvantages: microscale droplet manipulation by electrowetting-on-dielectric (EWOD). EWOD enables automated handling of droplets in an optically transparent platform that allows for in situ droplet observation. Separated phases are clearly visible, and the volumes of each phase are readily determined. Additionally, in considering the molecular crowding present in living cells, this work examines the role of a macromolecule in prompting LLPS. These results show that EWOD-driven droplet manipulation effectively interrogates the phase dynamics of ATPSs and macromolecular crowding in LLPS.


Asunto(s)
Dextranos/química , Electrohumectación , Polietilenglicoles/química , Tamaño de la Partícula , Transición de Fase , Propiedades de Superficie , Agua/química
7.
Electrophoresis ; 39(8): 1096-1103, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29383730

RESUMEN

Even identically designed autonomous microfluidic oscillators have device-to-device oscillation variability that arises due to inconsistencies in fabrication, materials, and operation conditions. This work demonstrates, experimentally and theoretically, that with appropriate capacitive coupling these microfluidic oscillators can be synchronized. The size and characteristics of the capacitive coupling needed and the range of input flow rate differences that can be synchronized are also characterized. In addition to device-to-device variability, there is also within-device oscillation noise that arises. An additional advantage of coupling multiple fluidic oscillators together is that the oscillation noise decreases. The ability to synchronize multiple autonomous oscillators is also a first step towards enhancing their usefulness as tools for biochemical research applications where multiplicate experiments with identical temporal-stimulation conditions are required.


Asunto(s)
Microfluídica/instrumentación , Diseño de Equipo , Utilización de Equipos y Suministros , Microfluídica/métodos , Investigación
8.
Reprod Fertil Dev ; 31(1): 93-104, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32188545

RESUMEN

Cryopreservation of gametes and embryos has played a critical role in successful assisted reproductive technologies in rodents, domestic farm species, endangered species and humans. With improved success, and changing needs, the utility of gamete or embryo cryopreservation has escalated. In this review we address some of the foundational history of mammalian cryobiology, species-specific utilities, fundamental understandings of cryoprotectant agents and their use in slow-rate freezing and vitrification, and expand on the recent success and uses of oocyte vitrification and warming. In the area of female gamete cryopreservation, emphasis will be placed on not just cell survival, but also perceived and measured affects of cryopreservation on intracellular structures and functions that affect subsequent completion of meiosis with chromatin segregation fidelity, normal fertilisation and embryonic developmental competence. We compare and contrast data from cow, mouse and humans with a focus on using species-comparative developmental biology to guide future studies for improving methodologies for all species. The application of the relatively new technology microfluidics is discussed in relation to moving gradually (i.e. changing the solution over cells in an automated fashion) compared with the stepwise manual movement of cells through changing solution currently used. This use of microfluidics to change the way cells are exposed to cryoprotectant agents can provide new insights into the effects of osmotic stress and cellular strain rates previously unappreciated, precise methods of computational and biological data acquisition and appreciation of morphometric changes to cellular structure in response to different osmotic stresses and strain rates achieved with varying cryoprotectant exposures. Collectively, these devices and methodologies provide a means of achieving incremental improvement of oocyte and zygote cryopreservation with normalised and improved developmental competence. Finally, we look to the past and the future to acknowledge the accomplishment of leaders in the field of mammalian gamete and embryo cryobiology, their inspirational works, their tireless dissemination of information and the potential of new technologies in bioengineering to improve the efficiency and safety of gamete and embryo cryopreservation.

9.
Dev Dyn ; 246(1): 7-27, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27761977

RESUMEN

BACKGROUND: To send meaningful information to the brain, an inner ear cochlear implant (CI) must become closely coupled to as large and healthy a population of remaining spiral ganglion neurons (SGN) as possible. Inner ear gangliogenesis depends on macrophage migration inhibitory factor (MIF), a directionally attractant neurotrophic cytokine made by both Schwann and supporting cells (Bank et al., 2012). MIF-induced mouse embryonic stem cell (mESC)-derived "neurons" could potentially substitute for lost or damaged SGN. mESC-derived "Schwann cells" produce MIF, as do all Schwann cells (Huang et al., a; Roth et al., 2007; Roth et al., 2008) and could attract SGN to a "cell-coated" implant. RESULTS: Neuron- and Schwann cell-like cells were produced from a common population of mESCs in an ultra-slow-flow microfluidic device. As the populations interacted, "neurons" grew over the "Schwann cell" lawn, and early events in myelination were documented. Blocking MIF on the Schwann cell side greatly reduced directional neurite outgrowth. MIF-expressing "Schwann cells" were used to coat a CI: Mouse SGN and MIF-induced "neurons" grew directionally to the CI and to a wild-type but not MIF-knockout organ of Corti explant. CONCLUSIONS: Two novel stem cell-based approaches for treating the problem of sensorineural hearing loss are described. Developmental Dynamics 246:7-27, 2017. © 2016 Wiley Periodicals, Inc.


Asunto(s)
Diferenciación Celular , Dispositivos Laboratorio en un Chip/normas , Células Madre Embrionarias de Ratones/citología , Neuronas/citología , Células de Schwann/citología , Animales , Implantes Cocleares/normas , Pérdida Auditiva/terapia , Oxidorreductasas Intramoleculares/fisiología , Factores Inhibidores de la Migración de Macrófagos/fisiología , Ratones , Vaina de Mielina/metabolismo , Ganglio Espiral de la Cóclea
10.
Mol Hum Reprod ; 23(4): 257-268, 2017 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-28130394

RESUMEN

Microfluidics can be considered both a science and a technology. It is defined as the study of fluid behavior at a sub-microliter level and the investigation into its application to cell biology, chemistry, genetics, molecular biology and medicine. There are at least two characteristics of microfluidics, mechanical and biochemical, which can be influential in the field of mammalian gamete and preimplantation embryo biology. These microfluidic characteristics can assist in basic biological studies on sperm, oocyte and preimplantation embryo structure, function and environment. The mechanical and biochemical characteristics of microfluidics may also have practical and/or technical application(s) to assisted reproductive technologies (ART) in rodents, domestic species, endangered species and humans. This review will consider data in mammals, and when available humans, addressing the potential application(s) of microfluidics to assisted reproduction. There are numerous sequential steps in the clinical assisted reproductive laboratory process that work, yet could be improved. Cause and effect relations of procedural inefficiencies can be difficult to identify and/or remedy. Data will be presented that consider microfluidic applications to sperm isolation, oocyte cumulus complex isolation, oocyte denuding, oocyte mechanical manipulation, conventional insemination, intracytoplasmic sperm injection, embryo culture, embryo analysis and oocyte and embryo cryopreservation. While these studies have progressed in animal models, data with human gametes and embryos are significantly lacking. These data from clinical trials are requisite for making future evidence-based decisions regarding the application of microfluidics in human ART.


Asunto(s)
Criopreservación/métodos , Técnicas de Cultivo de Embriones/métodos , Técnicas Analíticas Microfluídicas/métodos , Microfluídica/métodos , Oocitos/citología , Espermatozoides/citología , Animales , Blastocisto/citología , Blastocisto/efectos de los fármacos , Blastocisto/fisiología , Separación Celular/métodos , Criopreservación/instrumentación , Crioprotectores/química , Crioprotectores/farmacología , Femenino , Humanos , Masculino , Técnicas Analíticas Microfluídicas/tendencias , Microfluídica/instrumentación , Oocitos/efectos de los fármacos , Oocitos/fisiología , Inyecciones de Esperma Intracitoplasmáticas/métodos , Espermatozoides/efectos de los fármacos , Espermatozoides/fisiología
11.
Anal Chem ; 88(23): 11328-11334, 2016 12 06.
Artículo en Inglés | MEDLINE | ID: mdl-27808499

RESUMEN

Multiplex immunoassays are rapidly increasing in popularity due to the offered advantages of increased throughput and decreased sample volume requirements. However, a major weakness inherent to multiplex enzyme-linked immunosorbent assays (ELISA) is generation of false signals through reagent-driven cross-talk. Typically, multiplex platforms necessitate bath application of antibody cocktails, increasing probability of nonspecific antibody binding, especially when multiplexing large numbers of analytes. Aqueous two-phase systems (ATPS) exploiting the phase-separating polymers poly(ethylene) glycol (PEG) and dextran (DEX) have been used to compartmentalize antibodies and prevent cross-talk in multliplex, plate-based ELISA. However, the resulting protocol is tedious and lengthy, and requires too many user steps to be practical for widespread use. Here, we report an improved, user-friendly, cross-talk-free multiplex ELISA method in which dehydrated arrays of colocalized capture and detection antibodies in DEX are prepared on multiwell plates. Addition of a PEG-based sample buffer rehydrates antibody/DEX droplets for analysis. In this report, we demonstrate rehydrated ATPS components for multiplex ELISA retain the ability to compartmentalize antibodies and prevent cross-talk, while analytes in sample buffer partition into rehydrated DEX droplets for analysis. Utility of this method was demonstrated through successful quantitative analysis of five inflammatory cytokines in lipopolysaccharide-stimulated ThP-1 cell culture supernatant.


Asunto(s)
Anticuerpos/análisis , Dextranos/química , Ensayo de Inmunoadsorción Enzimática , Polietilenglicoles/química , Células Cultivadas , Citocinas/análisis , Citocinas/biosíntesis , Fluidoterapia , Humanos , Lipopolisacáridos/farmacología , Agua/química
12.
Mol Pharm ; 13(3): 895-906, 2016 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-26751280

RESUMEN

The endothelial cells lining the capillaries supplying the brain with oxygen and nutrients form a formidable barrier known as the blood-brain barrier (BBB), which exhibits selective permeability to small drug molecules and virtually impermeable to macromolecular therapeutics. Current in vitro BBB models fail to replicate this restrictive behavior due to poor integration of the endothelial cells with supporting cells (pericytes and astrocytes) following the correct anatomical organization observed in vivo. We report the coculture of mouse brain microvascular endothelial cells (b.End3), pericytes, with/without C8-D1A astrocytes in layered microfluidic channels forming three-dimensional (3D) bi- and triculture models of the BBB. The live/dead assay indicated high viability of all cultured cells up to 21 days. Trans-endothelial electrical resistance (TEER) values confirmed the formation of intact monolayers after 3 days in culture and showed statistically higher values for the triculture model compared to the single and biculture models. Screening the permeability of [(14)C]-mannitol and [(14)C]-urea showed the ability of bi- and triculture models to discriminate between different markers based on their size. Further, permeability of [(14)C]-mannitol across the triculture model after 18 days in culture matched its reported permeability across the BBB in vivo. Mathematical calculations also showed that the radius of the tight junctions pores (R) in the triculture model is similar to the reported diameter of the BBB in vivo. Finally, both the bi- and triculture models exhibited functional expression of the P-glycoprotein efflux pump, which increased with the increase in the number of days in culture. These results collectively indicate that the triculture model is a robust in vitro model of the BBB.


Asunto(s)
Astrocitos/citología , Barrera Hematoencefálica , Encéfalo/citología , Endotelio Vascular/citología , Pericitos/citología , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Animales , Astrocitos/metabolismo , Encéfalo/metabolismo , Permeabilidad Capilar , Técnicas de Cultivo de Célula , Permeabilidad de la Membrana Celular , Técnicas de Cocultivo , Endotelio Vascular/metabolismo , Técnicas In Vitro , Ratones , Microfluídica , Pericitos/metabolismo
13.
Langmuir ; 32(47): 12468-12475, 2016 11 29.
Artículo en Inglés | MEDLINE | ID: mdl-27571169

RESUMEN

The self-assembly of nanoparticles (NPs) is essential for emerging dispersion-based energy-conscious technologies. Of particular interest are micro- and macro-scale self-organizing superstructures that can bridge 2D/3D processing scales. Here we report the spontaneous assembly of CdTe NPs within an aqueous microdroplet suspended in soybean oil. The gradual diffusion of the water into the surrounding medium results in shrinking of the microdroplet, and a concomitant formation of branched assemblies from CdTe NPs that evolve in size from ∼50 µm to ∼1000 µm. The fractal dimension of NP assemblies increases from ∼1.7 to ∼1.9 during the assembly process. We found that constituents of the soybean oil enter the aqueous solution across the microdroplet interface and affect NP assembly. The obtained NP dendrites can be further altered morphologically by illumination with light that results in the disassembly of the NP dendrites. The use of this microheterogeneous dispersion platform with partially soluble hydrophilic and hydrophobic solvents highlights the sensitivity of the NP assembly process to environment and presents an opportunity to explore droplet-confined NP assembly.

14.
Gynecol Oncol ; 138(1): 181-9, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25913133

RESUMEN

BACKGROUND: Ovarian cancer grows and metastasizes from multicellular spheroidal aggregates within the ascites fluid. Multicellular tumor spheroids are therefore physiologically significant 3D in vitro models for ovarian cancer research. Conventional hanging drop cultures require high starting cell numbers, and are tedious for long-term maintenance. In this study, we generate stable, uniform multicellular spheroids using very small number of ovarian cancer cells in a novel 384 well hanging drop array platform. METHODS: We used novel tumor spheroid platform and two ovarian cancer cell lines (A2780 and OVCAR3) to demonstrate the stable incorporation of as few as 10 cells into a single spheroid. RESULTS: Spheroids had uniform geometry, with projected areas (42.60×10(3)µm-475.22×10(3)µm(2) for A2780 spheroids and 37.24×10(3)µm(2)-281.01×10(3)µm(2) for OVCAR3 spheroids) that varied as a function of the initial cell seeding density. Phalloidin and nuclear stains indicated cells formed tightly packed spheroids with demarcated boundaries and cell-cell interaction within spheroids. Cells within spheroids demonstrated over 85% viability. 3D tumor spheroids demonstrated greater resistance (70-80% viability) to cisplatin chemotherapy compared to 2D cultures (30-50% viability). CONCLUSIONS: Ovarian cancer spheroids can be generated from limited cell numbers in high throughput 384 well plates with high viability. Spheroids demonstrate therapeutic resistance relative to cells in traditional 2D culture. Stable incorporation of low cell numbers is advantageous when translating this research to rare patient-derived cells. This system can be used to understand ovarian cancer spheroid biology, as well as carry out preclinical drug sensitivity assays.


Asunto(s)
Neoplasias Ováricas/tratamiento farmacológico , Neoplasias Ováricas/patología , Línea Celular Tumoral , Ensayos de Selección de Medicamentos Antitumorales/métodos , Femenino , Ensayos Analíticos de Alto Rendimiento/métodos , Humanos , Esferoides Celulares
15.
Anal Chem ; 86(8): 4052-7, 2014 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-24654925

RESUMEN

Dextran hydrolysis-mediated conversion of polyethylene glycol (PEG)-dextran (DEX) aqueous two-phase system droplets to a single phase was used to directly visualize Dextranase activity. DEX droplets were formed either by manual micropipetting or within a continuous PEG phase by computer controlled actuation of an orifice connecting rounded channels formed by backside diffused light lithography. The time required for the two-phase to one-phase transition was dependent on the Dextranase concentration, pH of the medium, and temperature. The apparent Michaelis constants for Dextranase were estimated based on previously reported catalytic constants, the binodal polymer concentration curves for PEG-DEX phase transition for each temperature, and pH condition. The combination of a microfluidic droplet system and phase transition observation provides a new method for label-free direct measurement of enzyme activity.


Asunto(s)
Dextranasa/química , Técnicas Analíticas Microfluídicas/métodos , Dextranos/química , Concentración de Iones de Hidrógeno , Indicadores y Reactivos , Cinética , Polietilenglicoles/química , Temperatura
16.
Small ; 10(19): 4020-4029, 2014 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-24942855

RESUMEN

Adjustable fluidic structures play an important role in microfluidic systems. Fracture of multilayered materials under applied tension has been previously demonstrated as a convenient, simple, and inexpensive approach to fabricate nanoscale adjustable structures; here, it is demonstrated how to extend this concept to the microscale. This is achieved by a novel pairing of materials that leverages fracture mechanics to limit crack formation to a specified region, allowing to create size-controllable and adjustable microfluidic structures. This technique can be used to fabricate "normally closed" microfluidic channels that are completely reversible, a feature that is challenging to achieve in conventional systems without careful engineering controls. The adjustable microfluidic channels are then applied to mechanically lyse single cells, and subsequently manipulate the released nuclear chromatin, creating new possibilities for epigenetic analysis of single cells. This simple, versatile, and robust technology provides an easily accessible pathway to construct adjustable microfluidic structures, which will be useful in developing complex assays and experiments even in resource-limited settings.


Asunto(s)
Técnicas Analíticas Microfluídicas , Microfluídica/métodos , Animales , Materiales Biocompatibles/química , Núcleo Celular/metabolismo , Cromatina/química , Fuerza Compresiva , Dimetilpolisiloxanos/química , Epigénesis Genética , Ensayo de Materiales , Ratones , Células 3T3 NIH , Nanoestructuras/química , Nanotecnología , Oxígeno/química , Polímeros/química , Estrés Mecánico , Resistencia a la Tracción
17.
Electrophoresis ; 35(2-3): 245-57, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23893649

RESUMEN

In comparison to traditional in vitro cell culture in Petri dishes or well plates, cell culture in microfluidic-based devices enables better control over chemical and physical environments, higher levels of experimental automation, and a reduction in experimental materials. Over the past decade, the advantages associated with cell culturing in microfluidic-based platforms have garnered significant interest and have led to a plethora of studies for high throughput cell assays, organs-on-a-chip applications, temporal signaling studies, and cell sorting. A clear concern for performing cell culture in microfluidic-based devices is deciding on a technique to deliver and pump media to cells that are encased in a microfluidic device. In this review, we summarize recent advances in pumping techniques for microfluidic cell culture and discuss their advantages and possible drawbacks. The ultimate goal of our review is to distill the large body of information available related to pumps for microfluidic cell culture in an effort to assist current and potential users of microfluidic-based devices for advanced in vitro cellular studies.


Asunto(s)
Técnicas de Cultivo de Célula/instrumentación , Técnicas Analíticas Microfluídicas/instrumentación , Animales , Células Cultivadas , Diseño de Equipo , Ensayos Analíticos de Alto Rendimiento/instrumentación , Ratones
18.
Lab Chip ; 24(2): 197-209, 2024 01 17.
Artículo en Inglés | MEDLINE | ID: mdl-38093669

RESUMEN

This paper introduces a two-inlet, one-outlet lung-on-a-chip device with semi-circular cross-section microchannels and computer-controlled fluidic switching that enables a broader systematic investigation of liquid plug dynamics in a manner relevant to the distal airways. A leak-proof bonding protocol for micro-milled devices facilitates channel bonding and culture of confluent primary small airway epithelial cells. Production of liquid plugs with computer-controlled inlet channel valving and just one outlet allows more stable long-term plug generation and propagation compared to previous designs. The system also captures both plug speed and length as well as pressure drop concurrently. In one demonstration, the system reproducibly generates surfactant-containing liquid plugs, a challenging process due to lower surface tension that makes the plug formation less stable. The addition of surfactant decreases the pressure required to initiate plug propagation, a potentially significant effect in diseases where surfactant in the airways is absent or dysfunctional. Next, the device recapitulates the effect of increasing fluid viscosity, a challenging analysis due to higher resistance of viscous fluids that makes plug formation and propagation more difficult particularly in airway-relevant length scales. Experimental results show that increased fluid viscosity decreases plug propagation speed for a given air flow rate. These findings are supplemented by computational modeling of viscous plug propagation that demonstrates increased plug propagation time, increased maximum wall shear stress, and greater pressure differentials in more viscous conditions of plug propagation. These results match physiology as mucus viscosity is increased in various obstructive lung diseases where it is known that respiratory mechanics can be compromised due to mucus plugging of the distal airways. Finally, experiments evaluate the effect of channel geometry on primary human small airway epithelial cell injury in this lung-on-a-chip. There is more injury in the middle of the channel relative to the edges highlighting the role of channel shape, a physiologically relevant parameter as airway cross-sectional geometry can also be non-circular. In sum, this paper describes a system that pushes the device limits with regards to the types of liquid plugs that can be stably generated for studies of distal airway fluid mechanical injury.


Asunto(s)
Microfluídica , Surfactantes Pulmonares , Humanos , Surfactantes Pulmonares/metabolismo , Pulmón/metabolismo , Tensoactivos , Dispositivos Laboratorio en un Chip
19.
bioRxiv ; 2024 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-38260306

RESUMEN

Apical-out organoids produced through eversion triggered by extra-organoid extracellular matrix (ECM) removal or degradation are generally small, structurally variable, and limited for viral infection and therapeutics testing. This work describes ECM-encapsulating, stably-inverted apical-out human upper airway organoids (AORBs) that are large (~500 µm diameter), consistently spherical, recapitulate in vivo-like cellular heterogeneity, and maintain their inverted morphology for over 60 days. Treatment of AORBs with IL-13 skews differentiation towards goblet cells and the apical-out geometry allows extra-organoid mucus collection. AORB maturation for 14 days induces strong co-expression of ACE2 and TMPRSS2 to allow high-yield infection with five SARS-CoV-2 variants. Dose-response analysis of three well-studied SARS-CoV-2 antiviral compounds [remdesivir, bemnifosbuvir (AT-511), and nirmatrelvir] shows AORB antiviral assays to be comparable to gold-standard air-liquid interface cultures, but with higher throughput (~10-fold) and fewer cells (~100-fold). While this work focuses on SARS-CoV-2 applications, the consistent AORB shape and size, and one-organoid-per-well modularity broadly impacts in vitro human cell model standardization efforts in line with economic imperatives and recently updated FDA regulation on therapeutic testing.

20.
bioRxiv ; 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38798413

RESUMEN

Dysregulated neutrophil recruitment drives many pulmonary diseases, but most preclinical screening methods are unsuited to evaluate pulmonary neutrophilia, limiting progress towards therapeutics. Namely, high throughput therapeutic screening systems typically exclude critical neutrophilic pathophysiology, including blood-to-lung recruitment, dysfunctional activation, and resulting impacts on the air-blood barrier. To meet the conflicting demands of physiological complexity and high throughput, we developed an assay of 96-well Leukocyte recruitment in an Air-Blood Barrier Array (L-ABBA-96) that enables in vivo -like neutrophil recruitment compatible with downstream phenotyping by automated flow cytometry. We modeled acute respiratory distress syndrome (ARDS) with neutrophil recruitment to 20 ng/mL epithelial-side interleukin 8 (IL-8) and found a dose dependent reduction in recruitment with physiologic doses of baricitinib, a JAK1/2 inhibitor recently FDA-approved for severe COVID-19 ARDS. Additionally, neutrophil recruitment to patient-derived cystic fibrosis sputum supernatant induced disease-mimetic recruitment and activation of healthy donor neutrophils and upregulated endothelial e-selectin. Compared to 24-well assays, the L-ABBA-96 reduces required patient sample volumes by 25 times per well and quadruples throughput per plate. Compared to microfluidic assays, the L-ABBA-96 recruits two orders of magnitude more neutrophils per well, enabling downstream flow cytometry and other standard biochemical assays. This novel pairing of high-throughput in vitro modeling of organ-level lung function with parallel high-throughput leukocyte phenotyping substantially advances opportunities for pathophysiological studies, personalized medicine, and drug testing applications.

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