Browsing by Author "Yildirim, E."

Now showing 1 - 4 of 4

Citation - Scopus: 1
A Droplet Based Multi-Drug Screening System Controlled With Electrostatic Microvalves
(Chemical and Biological Microsystems Society, 2012) Yildirim, E.; Yıldırım, Ender; Özgür, E.; Külah, H.; 31835; Makine Mühendisliği
This paper presents a droplet-based drug effect analysis system utilizing electrostatically-actuated normallyclosed microvalves to screen the effect of multiple drugs on a single type of cell. Proposed system minimizes the need for off-chip equipment by utilizing parylene based electrostatic microvalves. Prototypes of the system were fabricated and tested using colored DI water and 3 μm diameter micro beads, emulating drugs and cells respectively. During the tests, micro beads could be successfully entrapped in 137 pl droplets. Tests carried out with yeast cells also yielded successful encapsulation of the cells. It was shown that, switching between the drugs could be achieved by applying 200 V dc to operate the microvalves.
Citation - Scopus: 1
An Electrostatically Actuated Parylene Microvalve for Lab-On-A-Chip Applications
(2011) Yildirim, E.; Yıldırım, Ender; Kulah, H.; Arikan, M.A.S.; 31835; Makine Mühendisliği
This paper presents a novel electrostatic microvalve to control in-plane flow on parylene based lab-on-a-chip-devices. Normally-closed design of the microvalve insulates the working fluid from the electric field, while providing low leakage up to 40 kPa inlet pressure. Prototypes are fabricated and tested for pull-in and flow characterization. Pull-in voltage is measured to be 150 V independent of the working fluid. No leakage is detected up to 20 kPa inlet pressure. © 2011 IEEE.
Citation - WoS: 12
Analysis and characterization of an electrostatically actuated in-plane parylene microvalve
(Iop Publishing Ltd, 2011) Yildirim, E.; Yıldırım, Ender; Kulah, H.; 31835; 120121; Makine Mühendisliği
This paper presents analysis and implementation of a simple electrostatic microvalve designed for use in parylene-based lab-on-a-chip devices. The microvalve utilizes an in-plane collapsing diaphragm. To investigate the pull-in behavior of the diaphragm and flow characteristics, a thorough analysis is carried out using the finite element method. Microvalves with different diaphragm radii are fabricated using surface micromachining techniques. Pull-in tests are carried out under the no-flow condition with air, oil and water as the working fluid. Test results show that the pull-in occurs around 20 V for 450 mu m radius diaphragms with oil and air. However, it is not possible to observe pull-in up to 100 V (both ac and dc) for the case of water as the working fluid, due to its relatively high dielectric constant and conductivity. The flow tests show that no leakage flow was observed up to 4 kPa inlet pressure under 85 V actuation potential. The leakage ratio becomes 17% at 10 kPa inlet pressure. It is observed that the leakage can be reduced controllably by increasing the actuation potential, enabling the precise control of the flow rate.
Citation - Scopus: 0
Phaseguide assisted liquid lamination for magnetic bead-based assays
(Chemical and Biological Microsystems Society, 2013) Phurimsak, C.; Yıldırım, Ender; Yildirim, E.; Trietsch, S.J.; Hankemeier, T.; Tarn, M.D.; Pamme, N.; Vulto, P.; Makine Mühendisliği
We demonstrate a simple, pump-free platform for performing rapid magnetic bead-based processes via their transfer through sequentially laminated liquid streams, made possible by the use of phaseguide technology. We have applied this strategy to two on-chip assays: (i) a streptavidin-biotin binding assay, and (ii) a sandwich immunoassay for the detection of C-reactive protein (CRP). Here, functionalized magnetic beads were pulled through alternating lanes of reagents and buffer solution, allowing multiple binding and washing processes to be reduced into a single step, significantly shortening procedural times compared to conventional multi-step bead-based assays.