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1

New microfluidic device for lactate dehydrogenase (LDH) activity analysis

Jędrych E., Mazur M., Grabowska-Jadach I., Brzózka Z.

Challenges of Modern Technology

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2012

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Vol. 3, no. 4

3--8

EN

In this paper, we present cytotoxicity analysis (determination of lactate dehydrogenase — LDH activity performed in a designed and fabricated microfl uidic system. This method allowed for analysis of a supernatant collected from A549 (human lung cancer) and HT-29 (human colon cancer epithelial) cells, which were incubated for 24 h with selected compounds. LDH is an intracellular enzyme present in tissues, which is released into the supernatant caused by membrane damage or cell lyses. In our tests, LDH-Cytotoxicity Assay Kit (BioVision) was used. The toxic eff ect of drugs was measured in the developed microsystem made of PDMS (poly(dimethylsiloxane)). Analytical reaction took place in the special designed microchannel geometry. Then, the LDH activity was measured at 490 nm using spectrophotometer. In subsequent experiments, appropriate conditions for measurements using a microfl uidic system were chosen. It was found that the selected reagent is sensitive to temperature changes and light exposure. Reaction time in the microsystem was determined by changes of fl ow rates of reagents. Afterwards, for the various reaction time, the toxic eff ect of 5-fl uorouracil, celecoxib and 1,4-dioxane was performed. The obtained results were compared with the results carried out in 96-well plates. Based on these results, it was noted that the enzymatic reaction time in the microsystem is shorter than in 96-well plate. Moreover, the advantage of using microsystem is also the small amount of reagents.

2

Microfluidic devices — application in anticancer studies

Jędrych E., Chudy M., Dybko A., Brzózka Z.

Challenges of Modern Technology

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2012

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Vol. 3, no. 2

3--5

EN

A rapidly growing pharmaceutical industry requires faster and more efficient ways to find and test new drugs. One of the new method for cell culture and examining the toxic effects of drugs is application of microfluidic systems. They provide new types of microenvironments and new methods for investigation of anticancer therapy. The use of microsystems is a solution that gives the opportunity to reduce not only cost and time, but also a number of tests on animals. In this paper we present designed and fabricated hybrid microfluidic systems which are applicable for cell culture, cell based cytotoxicity assays and photodynamic therapy procedures. Polydimethylsiloxane (PDMS) and sodium glass were used for fabrication of microdevices. The designed geometry of the microdevices includes cell culture microchambers and a concentration gradient generator (CGG). The CGG enables to obtain diff erent concentrations of tested drugs in a single step, which is a significant simplification of cytotoxicity assay procedure. In the designed microsystems three various cell lines (normal and carcinoma) were cultured and analyzed.

3

Photodynamic therapy procedures in the microfluidic system

Jędrych E., Pawlicka Z., Chudy M., Dybko A., Brzózka Z.

Challenges of Modern Technology

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2010

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Vol. 1, no. 1

30--33

EN

Evaluation of the effi ciency of photodynamic therapy (PDT) in a hybrid microfl uidic culture system was studied. The geometry of the utilized microsystem for PDT procedures consists microchambers for cell culture and microchannels, which create a concentration gradient generator (CGG). 5-aminolevulinic acid (ALA) as a precursor of the photosensitizer was used. The geometry of the microchip allowed to test diff erent concentrations of ALA in a single assay. Evaluation of the effi ciency of photodynamic therapy was determined 24 hours after PDT procedure (irradiation with light which induced accumulated in carcinoma cells). The performed microsystem contained two independent micropatterns, that enables examination simultaneously various cell lines (carcinoma and normal) or various photosensitizers.