A microfluidic device with fluorimetric detection for intracellular components analysis.

An integrated microfluidic system that coupled lysis of two cell lines: L929 fibroblasts and A549 epithelial cells, with fluorescence-based enzyme assay was developed to determine ß-glucocerebrosidase activity. The microdevice fabricated in poly(dimethylsiloxane) consists of three main parts: a chemical cell lysis zone based on the sheath flow geometry, a micromeander and an optical fibers detection zone. Unlike many methods described in literature that are designed to analyse intracellular components, the presented system enables to perform enzyme assays just after cell lysis process. It reduces the effect of proteases released in lysis process on determined enzymes. Glucocerebrosidase activity, the diagnostic marker for Gaucher's disease, is the most commonly measured in leukocytes and fibroblasts using 4-methylumbelliferyl-ß-D-glucopyranoside as synthetic ß-glucoside. The enzyme cleavage releases the fluorescent product, i.e. 4-methylumbelliferone, and its fluorescence is measured as a function of time. The method of enzyme activity determination described in this paper was adapted for flow measurements in the microdevice. The curve of the enzymatic reaction advancement was prepared for three reaction times obtained from application of different flow rates of solutions introduced to the microsystem. Afterwards, determined ß-glucocerebrosidase activity was recalculated with regard to 10(5) cells present in samples used for the tests. The obtained results were compared with a cuvette-based measurements. The lysosomal ß-glucosidase activities determined in the microsystem were in good correlation with the values determined during macro-scale measurements.

On the Unstructured Big Data Analytical Methods in Firms: Conceptual Model, Measurement, and Perception.

Firms face challenging analytical tasks at the advent of a growing amount of unstructured big data (BD). These data lead to radical shifts in their analytical strategies and market insights. Yet, the particular types of analytical methods remain in the literature still loosely scattered. This work stresses the unstructured BD analytics, first by capturing their unique characteristics and then by proposing a model for diagnosis of the analytical methods related to unstructured data (UD) inside the firms. We focus on five interrelated research aspects, by: explaining the essence of UD with the firms' environment; identifying and classifying the most important analytical methods in organizations to better understand UD; developing a conceptual model along with measures; and diagnosing the extent to which the unstructured analytical methods, beside the structured analytics, relate with firm performance (FP). Finally, this model is investigated from perspective of the two-communities theory in reference to data scientists and marketing researchers within the organizational environment. A model is tested on the basis of complementary analytical strategies: confirmatory and multigroup factor analyses and structural equation modeling, for which data (N = 356) were collected from international online survey. Results confirm a high level of adequacy of the conceptual model and superiority of unstructured over the structured analytics leading to FP, while the scalar invariance testing proves minor differences between groups in reference to two of the analytical methods.

Miniaturized tools and devices for bioanalytical applications: an overview.

This article presents an overview of various miniaturized devices and technologies developed by our group. Innovative, fast and cheap procedures for the fabrication of laboratory microsystems based on commercially available materials are reported and compared with well-established microfabrication techniques. The modules fabricated and tested in our laboratory can be used independently or they can be set up in different configurations to form functional measurement systems. We also report further applications of the presented modules e.g. disposable poly(dimethylsiloxane) (PDMS) microcuvettes, fibre optic detectors, potentiometric sensors platforms, microreactors and capillary electrophoresis (CE) microchips as well as integrated microsystems e.g. double detection microanalytical systems, devices for studying enzymatic reactions and a microsystem for cell culture and lysis.

Multi-function microsystem for cells migration analysis and evaluation of photodynamic therapy procedure in coculture.

Cell migration is an important physiological process, which is involved in cancer metastasis. Therefore, the investigation of cell migration may lead to the development of novel therapeutic approaches. In this study, we have successfully developed a microsystem for culture of two cell types (non-malignant and carcinoma) and for analysis of cell migration dependence on distance between them. Finally, we studied quantitatively the influence of photodynamic therapy (PDT) procedures on the viability of pairs of non-malignant (MRC5 or Balb/3T3) and carcinoma (A549) cells coculture. The proposed geometry of the microsystem allowed for separate introduction of two cell lines and analysis of cells migration dependence on distance between the cells. We found that a length of connecting microchannel has an influence on cell migration and viability of non-malignant cells after PDT procedure. Summarizing, the developed microsystem can constitute a new tool for carrying out experiments, which offers a few functions: cell migration analysis, carcinoma and non-malignant cells coculture, and evaluation of PDT procedure in the various steps of cell migration.

The microfluidic system for studies of carcinoma and normal cells interactions after photodynamic therapy (PDT) procedures.

This study reports on the use of a microsystem for evaluation of photodynamic therapy (PDT) procedures on the "mixed" (carcinoma-normal) cultures. Balb/3T3 (normal mouse embryo) and A549 (human lung carcinoma) cells were tested in separated and "mixed" cultures. Interactions and migration of cells cultured together were observed. The PDT procedures were examined in the hybrid (PDMS/glass) microsystem which contains cell culture microchambers integrated with network of microchannels. We investigated that the number of dead cells after PDT procedures is dependent on the kind of cell culture. Moreover, the influence of the carcinoma cells on the viability of normal cells in the "mixed" culture was observed.

Evaluation of photodynamic therapy (PDT) procedures using microfluidic system.

A hybrid PDMS/glass microfluidic system for evaluation of the efficiency of photodynamic therapy is presented. 5-aminolevulinic acid (ALA) was used as a precursor of photosensitizer. The geometry of the microdevice presented in this paper enables to test different concentrations of the photosensitizer in a single assay. The viability of the A549 cells was determined 24 h after PDT procedure (irradiation with light which induced a photosensitizer accumulated in carcinoma cells, λ=625 nm). The presented results confirmed the possibility to perform the photodynamic therapy process in vitro in microscale and the possibility to assess its effectiveness. Moreover, because two identical microstructures on a single chip were performed, the microchip can be used for examination simultaneously various cell lines (carcinoma and normal) or various photosensitizers.