Publications by authors named "Mustafa Sen"

Atherosclerosis is a chronic disease of the vascular wall driven by lipid accumulation and inflammation in the intimal layer of arteries, and its main complications, myocardial infarction and stroke, are the leading cause of mortality worldwide [1], [2]. Recent studies have identified Triggering receptor expressed on myeloid cells 2 (TREM2), a lipid-sensing receptor regulating myeloid cell functions [3], to be highly expressed in macrophage foam cells in experimental and human atherosclerosis [4]. However, the role of TREM2 in atherosclerosis is not fully known.

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Here, screen-printed carbon electrodes (SPCEs) were modified with ultrafine and mainly mono-disperse sea urchin-like tungsten oxide (SUWO) nanostructures synthesized by a simple one-pot hydrothermal method for non-enzymatic detection of dopamine (DA) and uric acid (UA) in synthetic urine. Sea urchin-like nanostructures were clearly observed in scanning electron microscope images and WO composition was confirmed with XRD, Raman, FTIR and UV-Vis spectrophotometer. Modification of SPCEs with SUWO nanostructures via the drop-casting method clearly reduced the R value of the electrodes, lowered the ∆Ep and enhanced the DA oxidation current due to high electrocatalytic activity.

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Here, a non-toxic, flexible, low-cost, and disposable multiwalled carbon nanotube (MWCNT)-based screen-printed electrode (SPE) was developed for non-invasive health monitoring applications. A novel MWCNT-based conductive paste formulation was prepared and optimized for printing SPEs using a computer numerical control (CNC)-made stencil. The electrodes were electrochemically characterized and subjected to physical stress to investigate their mechanical durability in extreme situations such as heavy exercise.

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Peroxidase mimicking FeO@Chitosan (FeO@Chi) nanozyme was synthesized and used for high-sensitive enzyme-free colorimetric detection of HO. The nanozyme was characterized in comparison with  FeO nanoparticles (NPs) using X-ray diffraction, Fourier-transform infrared spectroscopy, dynamic light scattering, and thermogravimetric analysis. The catalytic performance of FeO@Chi nanozyme was first evaluated by UV-Vis spectroscopy using 3,3',5,5'-tetramethylbenzidine.

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A growing number of sperm methylome analyses have identified genomic loci that are susceptible to paternal age effects in a variety of mammalian species, including human, bovine, and mouse. However, there is little overlap between different data sets. Here, we studied whether or not paternal age effects on the sperm epigenome have been conserved in mammalian evolution and compared methylation patterns of orthologous regulatory regions (mainly gene promoters) containing both conserved and non-conserved CpG sites in 94 human, 36 bovine, and 94 mouse sperm samples, using bisulfite pyrosequencing.

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In the present study, iodide-mediated 3,3',5,5'-tetramethylbenzidine (TMB)-HO reaction system was applied to a microfluidic paper-based analytical device (μPAD) for non-enzymatic colorimetric determination of HO. The proposed system is portable and incorporates a μPAD with a machine learning-based smartphone app. A smartphone app called "" capable of image capture, cropping and processing was developed to make the system simple and user-friendly.

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Herein, we report the fabrication of zinc oxide nanowire (ZnO NW) coated carbon fiber (CF) ultra-microelectrodes (UME). ZnO NWs were grown on commercial multifilament CFs through hydrothermal process in a teflon-lined autoclave at 90 °C for 4 h. X-ray diffraction (XRD), Raman and scanning electron microscopy characterizations showed that crystalline and well oriented NW structures were successfully obtained.

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In this study, a microfluidic paper-based analytical device (μPAD) was integrated with a smartphone app capable of offline (without internet access) image processing and analysis for the rapid colorimetric detection of glucose. A self-inking stamp was used to form hydrophobic channels on a piece of paper-towel due to its superior water absorption efficiency. As demonstrated, the developed sensor was employed for the colorimetric detection of glucose in artificial saliva in the linear scope of 0 - 1 mM with a calculated detection limit of 29.

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The PC12 cell line has been widely used as an model for studying neuronal differentiation and identifying the factors affecting the process. It has the ability to differentiate in the presence of nerve growth factor (NGF), resulting in neural extensions called dendrites and axons. In this study, first the impact of randomly distributed multi-walled carbon nanotubes (MWCNTs) in poly(ethylene glycol) dimethacrylate (PEGDMA) on PC12 cell differentiation was investigated in terms of neurite length, number of neurite per cell and differentiation marker gene expression profile.

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Even though large number of individually addressable electrodes can be effectively assembled in a small area, electrochemical detection methods have a relatively limited ability to detect multiple analytes compared to microdialysis probes and other analytic techniques. Here, we report a facile method for the electro-addressable functionalization of a probe comprising of closely spaced three individually addressable carbon fiber electrodes (CFEs) for the detection of nucleic acids. First, a multi electrode array probe comprising three adjacent CFEs was fabricated through pulling a three-barrel glass capillary with a single carbon fiber in each barrel.

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Optimization of nanofiber (NF) surface properties is critical to achieve an adequate cellular response. Here, the impact of conjugation of biomimetic aspartic acid (ASP) and glutamic acid (GLU) templated peptides with poly(lactic-co-glycolic acid) (PLGA) electrospun NF on osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs) was evaluated. Cold atmospheric plasma (CAP) was used to functionalize the NF surface and thus to mediate the conjugation.

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Herein, we present an overview of recent research progress in the development of micro/nanoelectrochemical probe and chip devices for the evaluation of three-dimensional (3D) cultured cells. First, we discuss probe devices: a general outline, evaluation of O consumption, enzyme-modified electrodes, evaluation of endogenous enzyme activity, and the collection of cell components from cell aggregates are discussed. The next section is focused on integrated chip devices: a general outline, electrode array devices, smart electrode array devices, droplet detection of 3D cultured cells, cell manipulation using dielectrophoresis (DEP), and electrodeposited hydrogels used for fabrication of 3D cultured cells on chip devices are discussed.

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In nanotechnological devices, mass transport can be initiated by pressure driven flow, diffusion or by employing molecular motors. As the scale decreases, molecular motors can be helpful as they are not limited by increased viscous resistance. Moreover, molecular motors can move against diffusion gradients and are naturally fitted for nanoscale transportation.

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We fabricated a platinum-based double barrel probe for scanning electrochemical microscopy-scanning ion conductance microscopy (SECM-SICM) by electrodepositing platinum onto the carbon nanoelectrode of the double barrel probe. The deposition conditions were optimized to attain highly sensitive electrochemical measurements and imaging. Simultaneous SECM-SICM imaging of electrochemical features and noncontact topography by using the optimized probe afforded high-resolution images of epidermal growth factor receptors (EGFR) on the membrane surface of the A431 cells.

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In this study, various amounts of oxygen were added to Ti-10Cr (mass%) alloys. It is expected that a large changeable Young's modulus, caused by a deformation-induced ω-phase transformation, can be achieved in Ti-10Cr-O alloys by the appropriate oxygen addition. This "changeable Young's modulus" property can satisfy the otherwise conflicting requirements for use in spinal implant rods: high and low moduli are preferred by surgeons and patients, respectively.

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We present a chip device with an array of 900 gourd-shaped microwells designed to pair single cells of different types. The device consists of interdigitated array (IDA) electrodes and uses positive dielectrophoresis to trap cells within the microwells. Each side of a microwell is on a different comb of the IDA, so that cells of different types are trapped on opposite sides of the microwells, leading to close cell pairing.

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A large scale integration (LSI)-based amperometric sensor is used for electrochemical evaluation and real-time monitoring of the alkaline phosphatase (ALP) activity of mouse embryoid bodies (EBs). EBs were prepared by the hanging drop culture of embryonic stem (ES) cells. The ALP activity of EBs with various sizes was electrochemically detected at 400 measurement points on a Bio-LSI chip.

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A lab-on-a-chip device is described for the electrochemical detection of alkaline phosphatase (ALP) secreted by transformed single HeLa cells. Detection on the chip device is based on local redox cycling at 256 individually addressable sensor points. Ring-disk electrodes (generator/collector) are arranged at individual sensor points to amplify the signal due to redox-cycling with only 32 connector pads.

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A new electrochemical assay for the detection of secreted alkaline phosphatase (SEAP) from transfectant HeLa cells is proposed using a microarray device and scanning electrochemical microscopy (SECM). The assay consists of two steps: the first is the incubation of a transfected cell in a microarray culture device covered with a substrate modified with anti-SEAP under physiological conditions without any additives. The array device consists of a 4 × 4 array of microwells having a size of 100 µm × 100 µm (diameter × depth).

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Boron is an industrially and biologically important element. However, the mechanisms of boron tolerance and its transport in bacteria and many other living systems are still not clearly understood. In this study, the boron resistance level of a boron-tolerant bacterium, Bacillus boroniphilus DSM 17376, was improved up to 300 mmol l(-1) boron, by employing an in vivo evolutionary engineering strategy based on batch selection under continuous exposure to gradually increasing boron stress levels.

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