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1
Content available Heater dedicated for Lab-on-a-chip systems
EN
The authors report a new construction of a heater, which can be applied in Lab-on-a-chip systems. The heater was fabricated on a ceramic plate as a solid support. A commercially available paste DuPont 5091D with positive temperature coefficient (PTC) was used as a resistive material. Next, metallic conductors were created using gold sputtering in argon enhanced plasma environment. Finally, the gold layers were bonded with connection wires. The developed heater can be integrated with microsystems dedicated for bioanalysis, enzymatic reactions and cell cultures.
EN
This paper describes a new contactless conductivity detector, whose electrodes are constructed of microchannels filled with solution of KCl - called pseudoelectrodes. The lab-on-a-chip microdevice was fabricated in poly(dimethylsiloxane) PDMS, using a moulding technique. The mould was made from a dry negative photoresist with a thickness of 50 µm. During the tests, the dimension and arrangement of pseudoelectrodes' microchannels were evaluated. The analyte was pumped into the microchannel using a syringe pump with a flow rate of 50 µL/min. Reproducible changes of the signal were obtained.
EN
Microfluidic systems are used in a wide range of applications, including medical diagnostics, cell engineering and bioanalytics. In this work we focused on “Lab-on-a-chip” microsystems for cell cultivation. A troublesome problem of gas bubbles entering microdevices causing signal interferences and cells damage was emphasized. A novel, integrated debubbler in the form of cylindrical traps covered with thin PDMS membrane was designed and manufactured. Demonstrated debubbler was successfully applied in a long-lasting culture of HT-29 cell aggregates.
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.
EN
Lysosomal storage disorders (LSDs) represent a group of more than 45 genetically inherited diseases caused by the absence or deficiency of one or more specific lysosomal enzymes. Nowadays, there is a lack of reports on fast, reliable methods for the diagnostics of LSDs. Currently applied diagnostic approaches generate many false-negative and false-positive results, which results in classification of patients to inappropriate therapeutic groups. Moreover, these methods are time-consuming (even 20 hours), and are carried out only in a few laboratories in the world. The goal of this work was to develop a method and a tool, a Point-of-Care system, for diagnostics of LSDs. The polymeric microdevice consists of a cell lysis module, a mixing microchannel and an optical detection module. The system enables to determine the activity of α-galactosidase (deficient in Fabry disease), and to reduce the time of analysis to 10 min. Due to its easy fabrication steps and low price, it seems to be a prospective tool for a point-of-care approach.
PL
Przedstawiono wyniki badań nad opracowaniem mikrodetektora konduktometrycznego z nowym rodzajem elektrod.
EN
The paper presents results research work on design of conductometric microdetector with electrodes of new type.
7
Content available Novel designs and technologies for cell engineering
EN
Microfluidic devices, such as lab-on-a-chip systems, are highly advantageous for cell engineering and cell based assays. It is a particularly useful approach for development of the in vitro cellular systems mimicking the in vivo environment. In this paper, a novel lab-on-a-chip device for three-dimensional human cell culture and anticancer drug testing is presented. Cells were cultured as Multicellular Tumor Spheroids (MCTS) — the best cancer tumor model developed so far. Diff erent designs were tested and novel technique of microfabrication in poly(dimethylsiloxane) was developed. MCTS were cultured in a system of polymeric microwells, with the network of microfluidic channels for culture medium flow. Design included optimal shear stress and proper nutrients supply for cultured cells. Final design provided MCTS culture for four weeks with the homeostasis-like state achievement, which is characteristic for the in vivo situation.
8
Content available Miniaturized device for a cell lysis process
EN
Single-cell studies are crucial for gaining knowledge on complexity of intracellular processes. In many cases, carrying researches into cell ingredients must be proceeded by a lysis process. Cell lysis leads to disintegration of the plasma membrane which is the barrier separating cell contents from the environment. However, investigations at the cellular level would not be possible without proper miniaturized tools, which offer many advantages as low reagents consumption, short reaction time, integration, automation or versatility. The goal of this work was to design and develop a microfluidic chip for a chemical cell lysis process. The geometry of a microsystem presented is based on the hydrodynamic focusing of a cell suspension stream. Applying non-denaturing cell lysis buffer enables to analyze released cell ingredients during next steps of investigations.
EN
One of the main scopes of modern cell engineering is development of cellular models that can replace animals in drug screening and toxicological tests, so called alternative methods. Construction of the alternative model is a very challenging task due to a richness of factors creating the in vivo environment. The monolayer cell culture — cultivation of adhesive cells on artificial surfaces such as glass or polymer — lack most of the in vivo-like interactions, but still is the only tool for the majority of applications. One of the most prospective approaches on mimicking in vivo environment is “Lab-on-a-chip” technology. Microfluidic devices offer lots of advantages over traditional in vitro culture, e.g. much higher cell volume-to-extracellular fluid volume ratio or possibility of regulation of hydrodynamic stress. This presentation aims to introduce latest advances of our team in microfluidic cell culture devices. Our novel approach is to cultivate three dimensional multicellular aggregates (spheroids) in microenvironments arranged in a microfluidic system. The geometry and materials of the system allow for cultivation, observation and analysis of multicellular spheroids. The results presented concern multicellular tumor spheroids (MCTS) rising from human cancer cells, which are considered to represent most of the conditionings of cancer tumor in vivo. The fully developed MCTS microdevice will be a reliable tool for anticancer drug screening, as the results most likely will be in a close accordance with the results obtained in vivo.
PL
Celem prezentowanej pracy było wykonanie pasywnego, wysokosprawnego mikromieszalnika przepływowego. Wykonany mikromieszalnik był strukturą w pełni trójwymiarową, w której mieszanie zachodzi głównie poprzez dyfuzję. Mikrokanały wykonano metodą mikrofrezowania w płytkach z PMMA, a następnie połączono ze sobą poprzez bondowanie termiczne. Parametry procesu bondowania dobrano w ten sposób, aby zminimalizować deformację mikrokanałów. Dodatkowo opracowano szybką metodę justowania mikrokanałów.
EN
This paper presents a highly efficient passive micromixer with a three-dimensional topography of microchannel that employs diffusion for mixing. The microchannels were created in PMMA plates by mechanical milling with a high frequency spindle. The PMMA plates with microchannels were thermally bonded to form sealed 3D micromixer structure. The developed device is easy to fabricate and has excellent working characteristics in the continuous-flow mode. In this paper we describe a simple method of microchannels’ adjustment.
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.
PL
Zaprezentowano wyniki badań nad opracowaniem nowej technologii wykonywania niebondowanych przepływowych mikroukładów chemicznych. Z filmu kapilarnego w procesie fotolitografii wykonano matryce. Zostały one użyte w procesie odlewania do wykonania nowego typu niebondowanego mikroukładu. Niebondowane mikroukłady wykonano przez zatopienie w strukturze polimeru matrycy z emulsji filmu kapilarnego. Po usieciowaniu polimeru emulsję usunięto z jego struktury pozostawiając sieć mikrokanatów.
EN
The paper presents results of developing of a new technology for fabrication of bonding-less (B-Less) microfluidic chemical systems. The matrixes for the microsystem preparation were made of a capilla film. They were used in a moulding process for a fabrication of B-Le: microsystem. For the fabrication of B-Less microsystem an emulsk of a capillary film was moulded inside of a polymer block. After p lymer crosslinking the emulsion was removed from the block and the microchannels were formed.
PL
Przedstawione wyniki dotyczą prac nad konstrukcją mikrokonduktometru przepływowego z nowym typem elektrod. Opisano wykonanie mikrokonduktometrów z dwóch materiałów: szkła i polimeru oraz z połączenia tych materiałów. W konstrukcji wykorzystano i porównano ze sobą trzy rodzaje elektrod pomiarowych: srebrzone mikrokanały, mikrokanały wypełnione elektrolitem i mikrokanały jednocześnie posrebrzone i wypełnione elektrolitem. Działanie wykonanych mikrokonduktometrów sprawdzono podczas pomiarów przewodnictwa wzorcowych roztworów KCI o różnym stężeniu.
EN
Presented results apply for works on construction of microfluidic conductometer with a new type of electrodes. Fabrication of conductometer from two materials was described: glass, polymer and combination of both of these materials. For construction, three types of electrodes were applied and compared: silver plated microchannels, microchannels filled with an electrolyte and microchannels simultaneously silver plated and filled with an electrolyte. Fabricated microconductometers were tested during the measurements of standard solutions with a different KCI concentrations.
14
Content available remote Optoelectronic system for water quality monitoring
EN
The paper presents a construction of a system for measurements of pH, concentration of calcium ions and concentration of heavy metal ions in water. Three fiber optic sensors in flow configuration were designed and tested. The system is fully automatic and can be used for water quality monitoring.
PL
Przedstawiono możliwości konstrukcji mikroukładów chemicznych z wykorzystaniem materiałów ceramicznych i polimerowych. Opracowano technikę trwałego i odwracalnego łączenia warstw ceramicznych i polimerowych, zależnie od dalszego przeznaczenia konstruowanego mikroukładu. W przypadku wykorzystania go w systemie z ciśnieniowym transportem mediów ciekłych przez układ konieczne jest bondowanie trwałe z wykorzystaniem plazmowej modyfikacji kolejnych warstw. W mikroukładach z transportem elektroosmotycznym próbek wystarczają jedynie siły wzajemnej adhezji warstw ceramicznych i polimerowych. W obu przypadkach ceramiczne elementy mikrosystemów należało pokryć warstwą szkliwa.
EN
The possibilities of the construction of microsystems using ceramics and polymers were presented in the paper. The technology of irreversible and reversible bonding of ceramic and polymer microsystems' layers was developed. The irreversible bonding is required only for microfluidic structures, in which samples and reagents are introduced into the system using pressure methods. For the systems with an electroosmotic reagents dosing adhesion forces between particular layers are enough to seal the microchannels. In both cases a glaze layer was screen-printed on ceramic plates to eliminate their surface roughness.
EN
The advantages and application perspectives for microcapillary electrophoresis (mi CE) are presented. The microchip based on a glass plate was fabricated. The separations of three FITC-labeled amino acids carried out with the conventional CE system and in the microchip were compared. The obtained results proved the usability of the microchip for mi CE process.
PL
W pracy przedstawiono modularny system fotoniczny wyposażony w programowalny układ FPGA dużej skali, optyczne łącza synchronicznej transmisji gigabitowej oraz zaimplementowane przemysłowe interfejsy komunikacyjne. Omówiono zadania funkcjonalne dla poszczególnych bloków urządzenia oraz krótko scharakteryzowano rozwiązanie warstwy sprzętowej uzyskane w realizacji niniejszego projektu. Przedstawiono praktyczne przykłady zastosowań systemu w fotonicznych układach pomiarowych.
EN
The paper concisely presents a functional idea and hardware realization of a Modular Photonic System. Solution of the system structure is composed of nondependent nodes connected by a network of gigabit optical links. The node construction was standardized via the application of a central, large FPGA chip, implementation of a considerable number of basic and universal communication interfaces (like Ethernet, USB, CAN, RS-232 and others), implementation of industrial interfaces (VME, VXI, ATCA in the future) and inclusion of universal PMC slots for photonic interfaces. Different functional requirements are realized in the FPGA chip. There is a possibility to reconfigure easily, reversibly and comparatively fast the FPGA chip. Tree sockets for universal embedded boards in the PMC standard were implemented. This provides exchangeability of dedicated interfaces for various devices. The FPGA chip realizes also fitting of requested functionalities for servicing of photonic devices or their interfaces. The work concerns application of the described system for quality determination of drinking water. A multi-parameter sensor was used for monitoring of drinking water parameters in industrial conditions. The following parameters are determined: pH, concentration of ions — calcium and heavy metals (zinc, cadmium, lead, mercury). The practical functionality of the constructed system has been checked during long term investigations. The calibration results for a number of used chemical sensors were presented. There are carried broad developmental works on a large, distributed, photonic network based, telemetrie system fit to the requirements of industrial conditions. The aim is that the photonic telemetrie system cooperates seamlessly with the large municipal water — sewage network. It enables monitoring of current system parameters in the municipal environment. Creation of maps for parameter distribution will be one of the aims.
EN
Fabrication of a ceramic-polymer hybrid structure with microchannel was accomplished. The structure for capillary electrophoresis is presented as an example system. The method of fabrication of such a structure is not complicated, makes use of well known technologies like thick film and photolithography, and commercially available materials. It could be used for manufacture of structures with different shapes and dimensions. The process relies on printing dielectric photosensitive paste onto a ceramic support, drying and exposing to UV light through a mask with suitable pattern, developing and firing. A thin glaze layer is deposited on the top of the structure in order to make possible reversible or irreversible bonding with transparent poly(dimethylsiloxane) (PDMS) and adapting this chip to measurements with the use of optical detection.
PL
Opracowano wytwarzanie ceramiczno-polimerowych struktur zawierających mikrokanał. Jako przykład zaprezentowano strukturę do elektroforezy kapilarnej. Metoda wytwarzania takich mikroukładów jest metodą prostą, wykorzystującą dobrze znane technologie, takie jak technologia grubowarstwowa czy fotolitografia i materiały komercyjnie dostępne. Może być wykorzystywana do wytwarzania struktur hybrydowych o różnej geometrii kanałów. Proces wytwarzania mikroukładów polega na nadrukowaniu światłoczułej pasty dielektrycznej na podłoże ceramiczne, wysuszeniu i naświetleniu przez fotomaskę z odpowiednim wzorem, wymyciu nienaświetlonej części warstwy i wypaleniu. Pokrycie struktury cienką warstwą szkliwiącą daje możliwość odwracalnego lub trwałego łączenia z transparentnym poli(dimetylosiloksanem) (POMS) i dostosowania takiego układu do pomiarów z detekcją optyczną.
EN
AgI-Ag2O-V2O5 glasses of mixed ionic and electronic conductivity were used as planar transducers for construction of all-solid-state NH4+ and NO3- selective microelectrodes. The sensors were prepared by direct deposition of the PVC-based membrane of an appropriate composition onto the transducer surface. Working parameters of the obtained internal solution-free miniaturized ion-selective electrodes were tested under flow conditions. The designed electrodes exhibited good long-term stability and high selectivity towards primary ions, comparable to the selectivity of conventional ion-selective electrodes based on PVC membranes containing nonactine and quaternary ammonium salts. The results have proven that AgI-Ag2,O-V205; glass material can be used for preparation of cheap, simple in structure all-solid-state ion-sensitive rnicroelectrodes.
PL
Kompozyt AgI-Ag2O-V2O5, wykazujący mieszane przewodnictwo jonowo-elektronowe, zastosowano jako planarny przetwornik w elektrodach na stałym podłożu, selektywnych na jony NH4+ oraz NONO3-. Miniaturowe elektrody jonoselektywne otrzymano przez nałożenie membran 7. piastyfikowanego polichlorku winylu) bezpośrednio na powierzchnię przetwornika. Parametiy pracy tak skonstruowanych elektrod wyznaczono w układzie pn-eprywowym. Charakteryzowały się one wysoką selektywnością na jony główne, porównywalną selektywnością klasycznych elektrod jonoselektywnych wykorzystujących nonakrynę oraz czwartorzędowe sole amoniowe. oraz dobrą stabilnością długoterminową. Otrzymane wyniki wykazały, że szklisty kompozyt AgI-Ag2,O-V205 może być stosowany w konstrukcji prostych i tanich jonoselektywnych mikroelektrod na stałym podłożu.
20
Content available remote Spectrophotometric analysis using poly( dimethylsiloxane) microfl uidic detectors
EN
Two constructions of microfluidic structures are described in this paper. A fibre optic micro cell for spectrophometric measurements and a micro cell for fluorescence experiments were designed and tested. The structures were made of polymer optical fibres which were incorporated into polymeric material Le. poly( dimethylsiloxane). The structures were tested as detectors in absorbance measurement (solutions of bromothymol blue with different pH were used) and in fluorescence tests (solution of fluoresceine was used).
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