Browsing by Subject "Optofluidic"

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Open Access
Femtosecond laser fabrication of fiber based optofluidic platform for flow cytometry applications
(SPIE, 2017) Serhatlioglu, Murat; Elbuken, Çağlar; Ortac, Bülend; Solmaz, Mehmet E.
Miniaturized optofluidic platforms play an important role in bio-analysis, detection and diagnostic applications. The advantages of such miniaturized devices are extremely low sample requirement, low cost development and rapid analysis capabilities. Fused silica is advantageous for optofluidic systems due to properties such as being chemically inert, mechanically stable, and optically transparent to a wide spectrum of light. As a three dimensional manufacturing method, femtosecond laser scanning followed by chemical etching shows great potential to fabricate glass based optofluidic chips. In this study, we demonstrate fabrication of all-fiber based, optofluidic flow cytometer in fused silica glass by femtosecond laser machining. 3D particle focusing was achieved through a straightforward planar chip design with two separately fabricated fused silica glass slides thermally bonded together. Bioparticles in a fluid stream encounter with optical interrogation region specifically designed to allocate 405nm single mode fiber laser source and two multi-mode collection fibers for forward scattering (FSC) and side scattering (SSC) signals detection. Detected signal data collected with oscilloscope and post processed with MATLAB script file. We were able to count number of events over 4000events/sec, and achieve size distribution for 5.95μm monodisperse polystyrene beads using FSC and SSC signals. Our platform shows promise for optical and fluidic miniaturization of flow cytometry systems. © 2017 SPIE.
Open Access
An optofluidic point-of-care device for quantitative investigation of erythrocyte aggregation during coagulation
(Elsevier B.V., 2018) Işıksaçan, Ziya; Hastar, Nurcan; Erel, Ö.; Elbüken, Çağlar
Coagulation, the process leading to clot formation with the interplay of blood constituents, is a self-regulating mechanism, requiring attentive and periodic monitoring for numerous clinical cases. Erythrocyte aggregation (EA) is a characteristic behaviour of erythrocytes forming reversible clumps especially in vitro at low shear rates. The effect of EA during coagulation is overlooked in whole blood (WB) clotting assays, and the relationship between the two mechanisms is not well understood. We present an optofluidic point-of-care device enabling quantitative investigation of EA from 50 μl WB during the coagulation process. Not only did we explain the coagulation mechanism considering EA, but we also demonstrated coagulation time measurement from optical EA analysis. The device consists of a disposable cartridge and a handheld analyzer containing a pinch valve for fluid motion and optics for transmitted light measurement. Following the sample introduction and cessation of the valve operation, the optical signal is the lowest due to shear-induced cell disaggregation. Then, the signal increases due to EA until reaching a peak, indicating blood clotting. The working principle was proven through clinical tests for prothrombin time measurement. In addition to revealing the relation between coagulation and aggregation, this device is promising for rapid WB coagulation time measurement.