RESUMEN
Floating cancer cells can survive the programmed death anoikis process after detaching from the extracellular matrix for the anchorage-dependent cells. Purification of viable floating cancer cells is essential for many biomedical studies, such as drug screening and cancer model development. However, the floating cancer cells are mixed with dead cells and debris in the medium supernatant. In this paper, we developed an inertial microfluidic device with sinusoidal microchannels to continuously remove dead cells and debris from viable cells. First, we characterized the differential inertial focusing properties of polystyrene beads in the devices. Then, we investigated the effects of flow rate on inertial focusing of floating MDA-MB-231 cells. At an optimal flow condition, purification of viable cells was performed and the purity of live cells was increased significantly from 19.9% to 76.6%, with a recovery rate of 69.7%. After separation, we studied and compared the floating and adherent MDA-MB-231 cells in terms of cell proliferation, protrusive cellular structure, and the expression of cyclooxygenase (Cox-2) which is related to epithelial-mesenchymal transition (EMT) changes. Meanwhile, drug screening of both floating and adherent cancer cells was conducted using a chemotherapeutic drug, doxorubicin (Dox). The results revealed that the floating cancer cells possess 30-fold acquired chemoresistance as compared to the adherent cancer cells. Furthermore, a three-dimensional (3D) double-cellular coculture model of human mammary fibroblasts (HMF) spheroid and cancer cells using the floating liquid marble technique was developed.
Asunto(s)
Separación Celular/instrumentación , Técnicas Analíticas Microfluídicas/instrumentación , Microfluídica/instrumentación , Adhesión Celular , Línea Celular Tumoral , Proliferación Celular , Células Cultivadas , Técnicas de Cocultivo , Doxorrubicina/farmacología , Evaluación Preclínica de Medicamentos , Ensayos de Selección de Medicamentos Antitumorales , Diseño de Equipo , Fibroblastos/citología , Humanos , Microesferas , Tamaño de la Partícula , Prostaglandina-Endoperóxido Sintasas/metabolismoRESUMEN
We explored the interaction of iodine with three crystalline type starches, corn, potato, and sweet potato starches using atomic force microscopy. Results revealed that starch molecules aggregated through interaction with iodine solution as well as iodine vapor. Detailed fine structures such as networks, chains, and super-helical structures were found in iodide solution tests. The nanostructures formed due to iodine adsorption could help to understand the formation and properties of the starch-iodine complex.
Asunto(s)
Yodo/metabolismo , Microscopía de Fuerza Atómica , Almidón/metabolismo , Ipomoea batatas/química , Solanum tuberosum/química , Almidón/aislamiento & purificación , Zea mays/químicaRESUMEN
Two Chinese jujube (Zizyphus jujuba) cultivars ('Huanghua' and 'Zhanhua') at unripe and ripe stages were investigated. During ripening, the weight, pH, hardness, and chewiness of both cultivars decreased while titratable acidity, total soluble solid content, and pectin contents increased. More than 75% pectins of the fruits were water-soluble pectin (WSP). Pectins shared the common major compositions of Gal, Rha and GalUA. For both cultivars, most of the chain widths were between 47 and 70 nm for unripe while less than 40 nm for ripe jujubes. Compared to unripe fruits, all pectins of ripe fruits had less percentage of wide and long pectin chains. All the pectin contents of cultivar 'Huanghua' changed to a degree greater than that of cultivar 'Zhanhua' during ripening. Changes of pectin nanostructure and neutral sugar composition might be responsible for the major physicochemical properties of jujubes.
Asunto(s)
Nanopartículas/química , Pectinas , Ziziphus , Pectinas/biosíntesis , Pectinas/química , Solubilidad , Especificidad de la Especie , Ziziphus/química , Ziziphus/metabolismoRESUMEN
Starch debranching is fundamental for understanding the structure-function relationships of starch. In this paper, atomic force microscopy (AFM) was used to investigate potato starch by isoamylase [EC 3.2.1.68] debranching at nanometer scale. The hydrolysates were separated by gel-permeation chromatography and the fractions were imaged. In addition to linear structures and branches, coiled structures were revealed in the intermediate hydrolysates. It is concluded that isoamylolysis is very useful for a better understanding of starch structure-property relationships.
Asunto(s)
Isoamilasa/metabolismo , Nanoestructuras/química , Raíces de Plantas/química , Solanum tuberosum/química , Almidón/química , Almidón/metabolismo , Conformación de Carbohidratos , Cromatografía en Gel , Aditivos Alimentarios/química , Aditivos Alimentarios/metabolismo , Geles , Hidrólisis , Microscopía de Fuerza Atómica , Nanoestructuras/ultraestructura , Tamaño de la Partícula , Almidón/ultraestructuraRESUMEN
Firmness and physicochemical properties of 2 Chinese cherry (Prunus pseudocerasus L.) cultivars (soft cultivar "Caode" and crisp cultivar "Bende") at unripe and ripe stages were investigated, and the qualitative and quantitative information about sodium carbonate-soluble pectin (SSP) nanostructures was determined by atomic force microscopy (AFM). The lengths and widths of the cherry SSPs are very regular: almost all of the widths and lengths of SSP single molecules are composed of several basic units. The widths of the SSP chains are 37, 47, 55, and 61 nm, and the lengths are 123, 202, and 380 nm in both cultivars. The results show that the firmer cherry groups (crisp fruit) contain more percentages of wide and short SSP chains than soft fruit, and the unripe groups contain more percentages of wide and long SSP chains than corresponding ripe groups. They indicate that those nanostructural characteristics of SSP are closely related with firmness of the Chinese cherries in each cultivar.