RESUMEN
The alveolar-capillary barrier is composed of epithelial and endothelial cells interacting across a fibrous extracelluar matrix (ECM). Although remodeling of the ECM occurs during several lung disorders, it is not known how fiber structure and mechanics influences cell injury during cyclic airway reopening as occurs during mechanical ventilation (atelectrauma). We have developed a novel in vitro platform that mimics the micro/nano-scale architecture of the alveolar microenvironment and have used this system to investigate how ECM microstructural properties influence epithelial cell injury during airway reopening. In addition to epithelial-endothelial interactions, our platform accounts for the fibrous topography of the basal membrane and allows for easy modulation of fiber size/diameter, density and stiffness. Results indicate that fiber stiffness and topography significantly influence epithelial/endothelial barrier function where increased fiber stiffness/density resulted in altered cytoskeletal structure, increased tight junction (TJ) formation and reduced barrier permeability. However, cells on rigid/dense fibers were also more susceptible to injury during airway reopening. These results indicate that changes in the mechanics and architecture of the lung microenvironment can significantly alter cell function and injury and demonstrate the importance of implementing in vitro models that more closely resemble the natural conditions of the lung microenvironment.
Asunto(s)
Barrera Alveolocapilar/fisiología , Matriz Extracelular/metabolismo , Técnicas In Vitro , Microtecnología , Atelectasia Pulmonar/etiología , Atelectasia Pulmonar/metabolismo , Actinas/metabolismo , Células Epiteliales Alveolares/metabolismo , Materiales Biomiméticos , Células Cultivadas , Citoesqueleto/metabolismo , Células Endoteliales/metabolismo , Humanos , Microtecnología/instrumentación , Microtecnología/métodos , Atelectasia Pulmonar/patología , Uniones EstrechasRESUMEN
Lab on a chip (LOC) systems provide interesting and low-cost solutions for key studies and applications in the biomedical field. Along with microfluidics, these microdevices make single-cell manipulation possible with high spatial and temporal resolution. In this work we have designed, fabricated and characterized a versatile and inexpensive microfluidic platform for on-chip selective single-cell trapping and treatment using laminar co-flow. The combination of co-existing laminar flow manipulation and hydrodynamic single-cell trapping for selective treatment offers a cost-effective solution for studying the effect of novel drugs on single-cells. The operation of the whole system is experimentally simple, highly adaptable and requires no specific equipment. As a proof of concept, a cytotoxicity study of ethanol in isolated hepatocytes is presented. The developed microfluidic platform controlled by means of co-flow is an attractive and multipurpose solution for the study of new substances of high interest in cell biology research. In addition, this platform will pave the way for the study of cell behavior under dynamic and controllable fluidic conditions providing information at the individual cell level. Thus, this analysis device could also hold a great potential to easily use the trapped cells as sensing elements expanding its functionalities as a cell-based biosensor with single-cell resolution.
Asunto(s)
Técnicas Biosensibles/instrumentación , Etanol/toxicidad , Hepatocitos/efectos de los fármacos , Técnicas Analíticas Microfluídicas/instrumentación , Análisis de la Célula Individual/instrumentación , Pruebas de Toxicidad/instrumentación , Animales , Línea Celular , Diseño de Equipo , Hepatocitos/citología , RatonesRESUMEN
UNLABELLED: Surface modification of biomaterials has been shown to improve the biological response to dental implants. The ability to create a controlled micro-texture on the implant via additive surface modification techniques with bioactive nanohydroxyapatite (nanoHA) may positively influence guided tissue regeneration. OBJECTIVE: The main goal of this study was to produce micro-fabricated SiO(2) surfaces modified with nanohydroxyapatite particles and to characterize their influence on the biological response of Human Dental-Pulp Mesenchymal Stem Cells (hDP-MSCs) and Streptococcus mutans. MATERIALS AND METHODS: A combined methodology of sol-gel and soft-lithography was used to produce micropatterned SiO(2) thin films with different percentages of nanoHA micro-aggregates. The surfaces were characterized by SEM/EDS, FT-IR/ATR, AFM, XPS quantitative elemental percentage and contact angle measurements. Biological characterization was performed using hDP-MSCs cultures, while Streptococcus mutans was the selected microorganism to evaluate the bacterial adhesion on the thin films. RESULTS: Micropatterned SiO(2) surfaces with 0%, 1% and 5% of nanoHA micro-aggregates were successfully produced using a combination of sol-gel and soft-lithography. These surfaces controlled the biological response, triggering alignment and oriented proliferation of hDP-MSCs and significant differences in the adhesion of S. mutans to the different surfaces. SIGNIFICANCE: The micropatterned surfaces exhibited biocompatible behavior that induced an oriented adhesion and proliferation of hDP-MSCs while SiO(2) presented low bacterial adhesion. These results show that the combination of sol-gel with soft-lithography is a good approach to create micropatterned surfaces with bioactive nanoparticles for guided tissue regeneration.
Asunto(s)
Materiales Biocompatibles/química , Materiales Biocompatibles Revestidos/química , Materiales Dentales/química , Durapatita/química , Nanoestructuras/química , Dióxido de Silicio/química , Anisotropía , Adhesión Bacteriana/fisiología , Biopelículas , Adhesión Celular/fisiología , Recuento de Células , Proliferación Celular , Supervivencia Celular/fisiología , Diseño Asistido por Computadora , Pulpa Dental/citología , Regeneración Tisular Dirigida/métodos , Humanos , Ensayo de Materiales , Células Madre Mesenquimatosas/fisiología , Microscopía de Fuerza Atómica , Microscopía Electrónica de Rastreo , Transición de Fase , Espectroscopía de Fotoelectrones , Espectrometría por Rayos X , Espectroscopía Infrarroja por Transformada de Fourier , Streptococcus mutans/fisiología , Propiedades de Superficie , HumectabilidadRESUMEN
UNLABELLED: Titanium implants are the gold standard in dentistry; however, problems such as gingival tarnishing and peri-implantitis have been reported. For zirconia to become a competitive alternative dental implant material, surface modification techniques that induce guided tissue growth must be developed. OBJECTIVES: To develop alternative surface modification techniques to promote guided tissue regeneration on zirconia materials, for applications in dental implantology. METHODS: A methodology that combined soft lithography and sol-gel chemistry was used to obtain isotropic micropatterned silica coatings on yttria-stabilized zirconia substrates. The materials were characterized via chemical, structural, surface morphology approaches. In vitro biological behavior was evaluated in terms of early adhesion and viability/metabolic activity of human osteoblast-like cells. Statistical analysis was conducted using one-way ANOVA/Tukey HSD post hoc test. RESULTS: Isotropic micropatterned silica coatings on yttria-stabilized zirconia substrates were obtained using a combined approach based on sol-gel technology and soft lithography. Micropatterned silica surfaces exhibited a biocompatible behavior, and modulated cell responses (i.e. inducing early alignment of osteoblast-like cells). After 7d of culture, the cells fully covered the top surfaces of pillar microstructured silica films. SIGNIFICANCE: The micropatterned silica films on zirconia showed a biocompatible response, and were capable of inducing guided osteoblastic cell adhesion, spreading and propagation. The results herein presented suggest that surface-modified ceramic implants via soft lithography and sol-gel chemistry could potentially be used to guide periodontal tissue regeneration, thus promoting tight tissue apposition, and avoiding gingival retraction and peri-implantitis.
Asunto(s)
Cerámica/química , Materiales Biocompatibles Revestidos/química , Materiales Dentales/química , Osteoblastos/fisiología , Dióxido de Silicio/química , Itrio/química , Circonio/química , Adhesión Celular/fisiología , Línea Celular , Proliferación Celular , Supervivencia Celular/fisiología , Cristalografía , Implantes Dentales , Regeneración Tisular Guiada Periodontal , Calor , Humanos , Indicadores y Reactivos , Ensayo de Materiales , Microscopía Confocal , Microscopía Electrónica de Rastreo , Oxazinas , Transición de Fase , Espectrometría Raman , Propiedades de Superficie , Factores de Tiempo , Difracción de Rayos X , XantenosRESUMEN
As a novel therapeutic application of microfabrication technology, a micromachined membrane-based biocapsule is described for the transplantation of protein-secreting cells without the need for immunosuppression. This new approach to cell encapsulation is based on microfabrication technology whereby immunoisolation membranes are bulk and surface micromachined to present uniform and well-controlled pore sizes as small as 10 nm, tailored surface chemistries, and precise microarchitecture. Through its ability to achieve highly controlled microarchitectures on size scales relevant to living systems (from microm to nm), microfabrication technology offers unique opportunities to more precisely engineer biocapsules that allow free exchange of the nutrients, waste products, and secreted therapeutic proteins between the host (patient) and implanted cells, but exclude lymphocytes and antibodies that may attack foreign cells. Microfabricated inorganic encapsulation devices may provide biocompatibility, in vivo chemical and mechanical stability, tailored pore geometries, and superior immunoisolation for encapsulated cells over conventional encapsulation approaches. By using microfabrication techniques, structures can be fabricated with spatial features from the sub-micron range up to several millimeters. These multi-scale structures correspond well with hierarchical biological structures, from proteins and sub-cellular organelles to the tissue and organ levels.
Asunto(s)
Separación Celular/instrumentación , Separación Celular/métodos , Animales , Materiales Biocompatibles , Trasplante de Células , Glucosa/aislamiento & purificación , Glucosa/metabolismo , Inmunoglobulinas/aislamiento & purificación , Insulina/aislamiento & purificación , Insulina/metabolismo , Islotes Pancreáticos/inmunología , Islotes Pancreáticos/fisiología , RatasRESUMEN
The ability to create biocompatible well-controlled membranes has been an area of great interest over the last few years, particularly for biosensor applications. The present study describes the fabrication and characterization of novel nanoporous micromachined membranes that exhibit selective permeability and low biofouling. Results indicate that such membranes can be fabricated with uniform pore sizes capable of the simultaneous exclusion of albumin and diffusion of glucose. Compared to polymeric membranes of similar pore size, micromachined silicon membranes allowed more than twice the amount of glucose diffusion after 240 min and complete albumin exclusion. Moreover, membranes exhibit no morphological change or degradability in the presence of biological proteins and fluids at 37 degrees C. The results point to the potential of using such membranes for implantable biosensor applications. With monodisperse pores sizes as small as 10 nm, these membranes offer advantages in their reproducibility, stability, and ability to be integrated in silicon-based biosensing technology.