Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Biomicrofluidics ; 9(3): 036502, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-26180572

RESUMEN

In recent years, there has been a dramatic increase in the use of poly(dimethylsiloxane) (PDMS) devices for cell-based studies. Commonly, the negative tone photoresist, SU8, is used to pattern features onto silicon wafers to create masters (SU8-Si) for PDMS replica molding. However, the complexity in the fabrication process, low feature reproducibility (master-to-master variability), silane toxicity, and short life span of these masters have been deterrents for using SU8-Si masters for the production of cell culture based PDMS microfluidic devices. While other techniques have demonstrated the ability to generate multiple devices from a single master, they often do not match the high feature resolution (∼0.1 µm) and low surface roughness that soft lithography masters offer. In this work, we developed a method to fabricate epoxy-based masters that allows for the replication of features with high fidelity directly from SU8-Si masters via their PDMS replicas. By this method, we show that we could obtain many epoxy based masters with equivalent features to a single SU8-Si master with a low feature variance of 1.54%. Favorable feature transfer resolutions were also obtained by using an appropriate Tg epoxy based system to ensure minimal shrinkage of features ranging in size from ∼100 µm to <10 µm in height. We further show that surface coating epoxy masters with Cr/Au lead to effective demolding and yield PDMS chambers that are suitable for long-term culturing of sensitive primary hippocampal neurons. Finally, we incorporated pillars within the Au-epoxy masters to eliminate the process of punching media reservoirs and thereby reducing substantial artefacts and wastage.

2.
Anal Chem ; 85(19): 9092-100, 2013 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-23947293

RESUMEN

In this manuscript, we discuss the development and clinical use of a thermoplastic modular microsystem for the high-throughput analysis of CTCs directly from whole blood. The modular system offers some innovative features that address challenges currently associated with many CTC platforms; it can exhaustively process 7.5 mL of blood in less than 45 min with recoveries >90%. In addition, the system automates the postselection CTC processing steps and thus, significantly reduces assay turnaround time (from selection to enumeration <1.5 h as compared to >8 h for many reported CTC platforms). The system is composed of 3 functional modules including (i) a thermoplastic CTC selection module composed of high aspect ratio (30 µm × 150 µm) channels containing anti-EpCAM antibodies that is scalable in terms of throughput by employing channel numbers ranging from 50 to 320; the channel number is user selected to accommodate the volume of blood that must be processed; (ii) an impedance sensor module for label-less CTC counting; and (iii) a staining and imaging module for the placement of released cells into a 2D array within a common imaging plane for phenotypic identification. To demonstrate the utility of this system, blood samples from patients with local resectable and metastatic pancreatic ductal adenocarcinoma (PDAC) were analyzed. We demonstrate the ability to select EpCAM positive CTCs from PDAC patients in high purity (>86%) and with excellent yields (mean = 53 CTCs per mL for metastatic PDAC patients) using our modular system. In addition, we demonstrate the ability to detect CTCs in PDAC patients with local resectable disease (mean = 11 CTCs per mL).


Asunto(s)
Separación Celular/métodos , Técnicas Analíticas Microfluídicas , Células Neoplásicas Circulantes/patología , Neoplasias Pancreáticas/sangre , Neoplasias Pancreáticas/patología , Humanos , Técnicas Analíticas Microfluídicas/instrumentación , Fenotipo , Células Tumorales Cultivadas
3.
Med Phys ; 12(2): 249-51, 1985.
Artículo en Inglés | MEDLINE | ID: mdl-4000087

RESUMEN

A method has been devised to enable users of half- and full-wave rectified x-ray sets to match the revised National Bureau of Standards (NBS) x-ray beam qualities obtained with a constant potential generator. The method provides a rapid technique for determining the added filter necessary to attain the same first half-value layers and nearly the same homogeneity coefficients as NBS. Beam qualities from 100 to 250 kVcp have been duplicated and used to perform blind calibrations at four beam qualities on each of two ion chambers owned by the National Bureau of Standards.


Asunto(s)
Radiometría/instrumentación , Aluminio , Calibración , Filtración , Rayos X
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA