Showing papers by "Meltem Elitas published in 2019"

Dielectrophoretic characterization and separation of monocytes and macrophages using 3D carbon-electrodes.

Abstract: Monocyte heterogeneity and its prevalence are revealed as indicator of several human diseases ranking from cardiovascular diseases to rheumatoid arthritis, chronic kidney diseases, autoimmune multiple sclerosis, and stroke injuries. When monocytes and macrophages are characterized and isolated with preserved genetic, phenotypic and functional properties, they can be used as label‐free biomarkers for precise diagnostics and treatment of various diseases. Here, the dielectrophoretic responses of the monocytes and macrophages were examined. We present 3D carbon‐electrode dielectrophoresis (carbon‐DEP) as a separation tool for U937 monocytes and U937 monocyte‐differentiated macrophages. The carbon‐electrodes advanced the usability and throughput of DEP separation, presented wider electrochemical stability. Using the 3D carbon‐DEP chip, we first identified the selective positive and negative DEP responses and specific crossover frequencies of monocytes and macrophages as their signatures for separation. The crossover frequency of monocytes and macrophages was 17 and 30 kHz, respectively. Next, we separated monocyte and macrophage subpopulations using their specific dielectrophoretic responses. Afterward, we used a fluorescence‐activated cell sorter to confirm our results. Finally, we enriched 70% of monocyte cells from the mixed cell population, in other words, concentration of monocyte cells to macrophage cells was five times increased, using the 30‐kHz, 10‐Vpp electric field and 1 μL/min flow rate.

Through the looking glass: real-time imaging in brachypodium roots and osmotic stress analysis

Abstract: To elucidate dynamic developmental processes in plants, live tissues and organs must be visualised frequently and for extended periods. The development of roots is studied at a cellular resolution not only to comprehend the basic processes fundamental to maintenance and pattern formation but also study stress tolerance adaptation in plants. Despite technological advancements, maintaining continuous access to samples and simultaneously preserving their morphological structures and physiological conditions without causing damage presents hindrances in the measurement, visualisation and analyses of growing organs including plant roots. We propose a preliminary system which integrates the optical real-time visualisation through light microscopy with a liquid culture which enables us to image at the tissue and cellular level horizontally growing Brachypodium roots every few minutes and up to 24 h. We describe a simple setup which can be used to track the growth of the root as it grows including the root tip growth and osmotic stress dynamics. We demonstrate the system’s capability to scale down the PEG-mediated osmotic stress analysis and collected data on gene expression under osmotic stress.

Design and Development of a Multi-functional Laparoscopic Device

Abstract: This study presents a design of a multifunctional laparoscopic appendectomy device that includes three surgical instruments commonly used in laparoscopic appendicitis surgeries: endoloop, endobag and scissors. It collects these three independent surgical tools in a single laparoscopic appendectomy device. These days there is a trend of moving to multi-functional surgery devices during minimally invasive surgery. The main reasons behind the minimal invasive surgery are to avoid changing the devices several times during the operation, to reduce the time spent in operation, to increase the efficiency of the operation, to facilitate the follow-up of the camera and devices, and to leave trocars to be used for other surgical instruments. The multi-functional appendectomy device that, we present here, provides these benefits. The standard trocar entries are appropriate for its usage. The presented multifunctional laparoscopic appendectomy device offers more practical use in comparison to individual devices. On the other hand, development of these multi-functional surgery devices can be directly enhanced to the robotic surgery devices.