Browsing by Author "Güler, M. T."

Now showing 1 - 4 of 4

Open Access
Focusing-free impedimetric differentiation of red blood cells and leukemia cells: a system optimization
(Elsevier, 2020) Bilican, İ.; Güler, M. T.; Serhatlıoğlu, Murat; Kırındı, T.; Elbüken, Çağlar
A focusing-free microfluidic impedimetric cell detection system is developed. The effect of the channel dimensions, solution conductivity, excitation voltage, and particle size on impedimetric signal outputs were optimized to increase the sensitivity of the system. Conventional microfabrication techniques were adapted to obtain low height, resealable microchannels. The geometry optimization was performed by a combination of analytical, numerical and experimental approaches. The results demonstrate that reliable impedimetric particle differentiation can be achieved without any labeling or particle focusing. The system parameters were studied and rule-of-thumb design criteria were provided. Finally, using the developed system, red blood cells and leukemia cells were experimentally detected and differentiated. Thanks to its simplicity, the focusing-free cell differentiation system may find applications in several cellular diagnostic uses.
Open Access
Lab-on-a-chip platforms for disease detection and diagnosis
(Wiley Blackwell, 2018) Işıksaçan, Ziya.; Güler, M. T.; Kalantarifard, Ali; Asghari, Mohammad; Elbüken, Çağlar; Altıntaş, Z.
The adaptation of silicon electronics microfabrication technologies to other materials led to the birth of microfluidic systems. These systems allow investigation and control of fluids at micrometer scale. Due to the wide variety of applications of microfluidics, several research groups have been involved in the development of basic microfluidic components. After the development of fundamental fluid handling components, these technologies have been integrated for numerous applications one of which is disease detection and diagnostics. This chapter summarizes the microfluidic platforms that are mature enough for adaptation towards disease detection. The microfluidic platforms were discussed under six categories: continuous flow, paper‐based, microdroplets, digital microfluidics, compact disk‐based, and wearable platforms. Seminal works and recent developments in each category have been presented together with successful commercial examples. It is worth noting that some studies straddle more than one category, therefore, this classification is strictly for the ease of the reader. Each section discusses the benefits of a specific microfluidic platform. Engineering of microfluidic systems lead to lab‐on‐a‐chip (LOC) systems that can be used for diagnostics whether at point‐of‐care as portable systems or at clinical settings as advanced detection systems. The increasing awareness on personalized treatments proves the importance of such democratizing technologies. The increasing market share of microfluidic platforms in nearly all sectors is also an indication of the bright future of microfluidics and lab‐on‐a‐chip systems. The chapter is ended with a future outlook.
Open Access
Self-powered disposable prothrombin time measurement device with an integrated effervescent pump
(Elsevier B.V., 2018) Güler, M. T.; Işıksaçan, Ziya; Serhatlıoğlu, Murat; Elbüken, Çağlar
Coagulation is an essential physiological activity initiated by the interaction of blood components for clot formation. Prothrombin time (PT) measurement is a clinical test for the assessment of the extrinsic/common pathways of coagulation cascade. Periodic measurement of PT is required under numerous conditions including cardiovascular disorders. We present a self-powered microfluidic device for quantitative PT measurement from 50 μl whole blood. The entire platform is disposable and does not require any external pumping, power, or readout units. It consists of a 3D-printed effervescent pump for CO2 generation from a chemical reaction, a cartridge for two-channel fluid flow (blood and water), and a grid for the quantification of fluid migration distance. Following the introduction of the fluids to the corresponding channel inlets, marking the coagulation start, an acid-base reaction is triggered for gas generation that drives the fluids within the channels. When the blood coagulates, its flow in the channel is halted. At that point, the distance water has travelled is measured using the grid. This distance correlates with PT as demonstrated through clinical tests with patient samples. This single-unit device has a potential for rapid evaluation and periodic monitoring of PT in the clinical settings and at the point-of-care.
Open Access
Tape'n roll inertial microfluidics
(Elsevier, 2019) Asghari, Mohammad; Serhatlıoğlu, Murat; Güler, M. T.; Elbüken, Çağlar
Particle focusing and separation in microfluidic devices are critical for biological and medical applications. Inertial microfluidics is used for high throughput bio-particle focusing and separation. Most of the inertial microfluidic systems use planar structures for squeezing the particles in streams. Particle manipulation in 3D structures is often overlooked due to the complexity of the fabrication. In this study, we introduce some novel microchannel designs for inertial microfluidics by using a simple fabrication method that allows construction of both 2D and 3D structures. First, inertial migration of particles in 2D layouts including straight, spiral, and square spiral channels is investigated. Afterward, by applying a “tape’n roll” method, helical and double oriented spiral channels are configured and unexplored inertial migration behaviours are observed. Thanks to the simplicity of the fabrication and the unique characteristics of the new designs, high performance microfluidic inertial migration results can be obtained without any need for complicated microfabrication steps. The design optimization cycle can also be shortened using a computational approach we introduce in this study.