Use of a Microvalve-controlled Microfluidic Device in a Chemotaxis Assay of Tetrahymena pyriformis in Response to Amino Acids Released from Bacteria

남성원,Danny van Noort,양윤선,김소현,박성수 한국바이오칩학회 2007 BioChip Journal Vol.1 No.2

In this study, we introduce a microfluidic device equipped with pneumatically-actuated valves, generating a linear gradient of chemoeffectors to quantify the chemotactic response of Tetrahymena pyriformis, a freshwater ciliate to amino acids excreted from bacteria. The microfluidic device was fabricated from an elastomer, polydimethylsiloxane (PDMS), using multi-layer soft lithography. The components of the device include electronically-controlled pneumatic microvalves, microchannels and microchambers. The linear gradient of the chemoeffectors was established by releasing a chemical from a ciliatefree microchamber into a microchamber containing the ciliate. The ciliate showed chemotactic behaviours by either swimming toward or avoiding the gradient. By counting the number of ciliate residing in each microchamber, we obtained a precise timeresponse curve. The ciliate in the microfluidic device were sensitive enough to be attracted to 0.1 femtomolar aspartate, suggesting that ciliates as a predator can track down food patches composed of a few bacterial cells. With the use of receptor inhibitors, such as tetraethyl ammonium (TEA) or the grape polyphenol resveratol, we have also demonstrated that the calcium signalling plays an important role in motility and following chemotactic behaviours.

Intestine on a Chip

Meiying CHI,Danny VAN NOORT,Sungsu PARK 한국생물공학회 2013 한국생물공학회 학술대회 Vol.2013 No.4

A Microbore Tubing Based Spiral for Multistep Cell Fractionation

Pasitka, Laura,van Noort, Danny,Lim, Wanyoung,Park, Sungsu,Mandenius, Carl-Fredrik American Chemical Society 2018 ANALYTICAL CHEMISTRY - Vol.90 No.21

<P>Cells were separated with the aid of a multistep spiral fractionation device, utilizing hydrodynamic forces in a spiral tubing. The spiral was fabricated using “off-the-shelf” microbore tubing, allowing for cheap and fast prototyping to achieve optimal cell separation. As a first step, a model system with 20 and 40 μm beads was used to demonstrate the effectiveness of the multistep separation device. With an initial purity of 5%, a separation purity of 83% was achieved after a two-step separation with the addition of 0.1% polyethylene glycol (PEG)-8000. Next, doxorubicin-resistant polyploid giant breast cancer cells (MDA-MB-231) were separated from doxorubicin-sensitive monoploid small breast cancer cells in the same fashion as the beads, resulting in a purity of around 40%, while maintaining a cell viability of more than 90%. Combined with basic cell analytical methods, the hydrodynamic separation principle of the device could be envisaged to be useful for a variety of cell fractionation needs in cell biology and in clinical applications.</P> [FIG OMISSION]</BR>

Endocrine system on chip for a diabetes treatment model

Nguyen, Dao Thi Thuy,van Noort, Danny,Jeong, In-Kyung,Park, Sungsu IOP Publishing 2017 Biofabrication Vol.9 No.1

<P>The endocrine system is a collection of glands producing hormones which, among others, regulates metabolism, growth and development. One important group of endocrine diseases is diabetes, which is caused by a deficiency or diminished effectiveness of endogenous insulin. By using a microfluidic perfused 3D cell-culture chip, we developed an 'endocrine system on chip' to potentially be able to screen drugs for the treatment of diabetes by measuring insulin release over time. Insulin-secreting beta-cells are located in the pancreas, while L-cells, located in the small intestines, stimulate insulin secretion. Thus, we constructed a co-culture of intestinal-pancreatic cells to measure the effect of glucose on the production of glucagon-like peptide-1 (GLP-1) from the L-cell line (GLUTag) and insulin from the pancreatic beta-cell line (INS-1). After three days of culture, both cell lines formed aggregates, exhibited 3D cell morphology, and showed good viability (> 95%). We separately measured the dynamic profile of GLP-1 and insulin release at glucose concentrations of 0.5 and 20 mM, as well as the combined effect of GLP-1 on insulin production at these glucose concentrations. In response to glucose stimuli, GLUTag and INS-1 cells produced higher amounts of GLP-1 and insulin, respectively, compared to a static 2D cell culture. INS-1 combined with GLUTag cells exhibited an even higher insulin production in response to glucose stimulation. At higher glucose concentrations, the diabetes model on chip showed faster saturation of the insulin level. Our results suggest that the endocrine system developed in this study is a useful tool for observing dynamical changes in endocrine hormones (GLP-1 and insulin) in a glucose-dependent environment. Moreover, it can potentially be used to screen GLP-1 analogues and natural insulin and GLP-1 stimulants for diabetes treatment.</P>

Effective mixing in a microfluidic chip using magnetic particles

Lee, Seung Hwan,van Noort, Danny,Lee, Ji Youn,Zhang, Byoung-Tak,Park, Tai Hyun Royal Society of Chemistry 2009 Lab on a chip Vol.9 No.3

<P>We present a novel active mixing method in a microfluidic chip, where the controlled stirring of magnetic particles is used to achieve an effective mixing of fluids. To perform mixing, the ferromagnetic particles were embedded and manipulated under the influence of a rotating magnetic field. By aligning the magnetic beads along the magnetic field lines, rod-like structures are formed, functioning as small stir bars. Under higher flow conditions the particles did not form the typical rod structure but rather formed aggregates, which were even more beneficial for mixing. Our system reached a 96% mixing efficiency in a relatively short distance (800 µm) at a flow rate of 1.2–4.8 mm/s. These results demonstrate that our mixing method is useful for microfluidic devices with low aspect ratios and molecules with large molecular weights.</P> <P>Graphic Abstract</P><P>We present the design and fabrication of a novel mixing device, where the controlled stirring of magnetic particles is used to achieve an effective mixing in a microfluidic chip. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b814371d'> </P>

A biological sensor platform using a pneumatic-valve controlled microfluidic device containing <i>Tetrahymena pyriformis</i>

Nam, Seong-Won,Noort, Danny Van,Yang, Yoonsun,Park, Sungsu Royal Society of Chemistry 2007 Lab on a chip Vol.7 No.5

<P>In this study, we introduce a microfluidic device equipped with pneumatically actuated valves, generating a linear gradient of chemoeffectors to quantify the chemotactic response of <I>Tetrahymena pyriformis</I>, a freshwater ciliate. The microfluidic device was fabricated from an elastomer, poly(dimethylsiloxane) (PDMS), using multi-layer soft lithography. The components of the device include electronically controlled pneumatic microvalves, microchannels and microchambers. The linear gradient of the chemoeffectors was established by releasing a chemical from a ciliate-free microchamber into a microchamber containing the ciliate. The ciliate showed chemotactic behaviours by either swimming toward or avoiding the gradient. By counting the number of ciliates residing in each microchamber, we obtained a precise time–response curve. The ciliates in the microfluidic device were sensitive enough to be attracted to 10 pmol glycine-proline, which indicates a 10<SUP>5</SUP> increase in the ciliate's known sensitivity. With the use of blockers, such as <SMALL>DL</SMALL>-2-amino-5-phosphonopentanoic acid (APPA) or lanthanum chloride (LaCl<SUB>3</SUB>), we have demonstrated that the NMDA (<I>N</I>-methyl-<SMALL>D</SMALL>-aspartate) receptor plays a critical role in the perception of chemoeffectors, whereas the Ca<SUP>2+</SUP> channel is related to the motility of the ciliate. These results demonstrate that our microfluidic chemotaxis assay system is useful not only for the study of ciliate chemotaxis but also for a better understanding of the signal transduction mechanism on their receptors.</P> <P>Graphic Abstract</P><P>Ciliates in the left chamber chemotactically moved to the right chamber containing 10 pM glycine-proline within 10 min after the connecting microvalve between the two chambers was opened. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b617357h'> </P>

Biomolecular theorem proving on a chip: a novel microfluidic solution to a classical logic problem.

Lee, Seung Hwan,van Noort, Danny,Yang, Kyung-Ae,Lee, In-Hee,Zhang, Byoung-Tak,Park, Tai Hyun Royal Society of Chemistry 2012 Lab on a chip Vol.12 No.10

<P>Biomolecules inside a microfluidic system can be used to solve computational problems, such as theorem proving, which is an important class of logical reasoning problems. In this article, the Boolean variables (literals) were represented using single-stranded DNA molecules, and theorem proving was performed by the hybridization and ligation of these variables into a double-stranded 'solution' DNA. Then, a novel sequential reaction mixing method in a microfluidic chip was designed to solve a theorem proving problem, where a reaction loop and three additional chambers were integrated and controlled by pneumatic valves. DNA hybridization, ligation, toehold-mediated DNA strand displacement, exonuclease I digestion, and fluorescence detection of the double-stranded DNA were sequentially performed using this platform. Depending on the computational result, detection of the correct answer was demonstrated based on the presence of a fluorescence signal. This result is the first demonstration that microfluidics can be used to facilitate DNA-based logical inference.</P>

A microfluidic platform for implementing molecular logic gate with fluorescent chemosensors

Songzi Kou,Han Na Lee,Danny van Noort,K. M. K. Swamy,So Hyun Kim,Jung Hyun Soh,Seong-Won Nam,Juyoung Yoon,Sungsu Park 한국생물공학회 2008 한국생물공학회 학술대회 Vol.2008 No.4

Solenoid Driven Pressure Valve System: Toward Versatile Fluidic Control in Paper Microfluidics

Kim, Taehoon H.,Hahn, Young Ki,Lee, Jungmin,van Noort, Danny,Kim, Minseok S. American Chemical Society 2018 ANALYTICAL CHEMISTRY - Vol.90 No.4

<P>As paper-based diagnostics has become predominantly driven by more advanced microfluidic technology, many of the research efforts are still focused on developing reliable and versatile fluidic control devices, apart from improving sensitivity and reproducibility. In this work, we introduce a novel and robust paper fluidic control system enabling versatile fluidic control. The system comprises a linear push–pull solenoid and an Arduino Uno microcontroller. The precisely controlled pressure exerted on the paper stops the flow. We first determined the stroke distance of the solenoid to obtain a constant pressure while examining the fluidic time delay as a function of the pressure. Results showed that strips of grade 1 chromatography paper had superior reproducibility in fluid transport. Next, we characterized the reproducibility of the fluidic velocity which depends on the type and grade of paper used. As such, we were able to control the flow velocity on the paper and also achieve a complete stop of flow with a pressure over 2.0 MPa. Notably, after the actuation of the pressure driven valve (PDV), the previously pressed area regained its original flow properties. This means that, even on a previously pressed area, multiple valve operations can be successfully conducted. To the best of our knowledge, this is the first demonstration of an active and repetitive valve operation in paper microfluidics. As a proof of concept, we have chosen to perform a multistep detection system in the form of an enzyme-linked immunosorbent assay with mouse IgG as the target analyte.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2018/ancham.2018.90.issue-4/acs.analchem.7b03791/production/images/medium/ac-2017-03791a_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac7b03791'>ACS Electronic Supporting Info</A></P>

Endocrine System on a Chip: a Model for Diabetes

DAO THI THUY NGUYEN,So Hyun KIM,Seunghan OH,Danny VAN NOORT,Sungsu PARK 한국생물공학회 2013 한국생물공학회 학술대회 Vol.2013 No.4