WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

Browse

Filters

2017 - 201972020 - 202415

Settings

Author: search.filters.author.Arslan Yıldız, AhuHas files: Yes

Search Results

Now showing 1 - 10 of 22
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    The Soft Nanodots as Fluorescent Probes for Cell Imaging: Analysis of Cell and Spheroid Penetration Behavior of Single Chain Polymer Dots
    (Wiley, 2024) Yücel, Müge; Onbaş, Rabia; Arslan Yıldız, Ahu; Yıldız, Ümit Hakan
    This study describes the formation, size control, and penetration behavior of polymer nanodots (Pdots) consisting of single or few chain polythiophene-based conjugated polyelectrolytes (CPEs) via nanophase separation between good solvent and poor solvent of CPE. Though the chain singularity may be associated with dilution nanophase separation suggests that molecules of a good solvent create a thermodynamically driven solvation layer surrounding the CPEs and thereby separating the single chains even in their poor solvents. This statement is therefore corroborated with emission intensity/lifetime, particle size, and scattering intensity of polyelectrolyte in good and poor solvents. Regarding the augmented features, Pdots are implemented into cell imaging studies to understand the nuclear penetration and to differentiate the invasive characteristics of breast cancer cells. The python based red, green, blue (RGB) color analysis depicts that Pdots have more nuclear penetration ability in triple negative breast cancer cells due to the different nuclear morphology in shape and composition and Pdots have penetrated cell membrane as well as extracellular matrix in spheroid models. The current Pdot protocol and its utilization in cancer cell imaging are holding great promise for gene/drug delivery to target cancer cells by explicitly achieving the very first priority of nuclear intake. The penetration capability of cationic soft nanodots in to tumor models of breast cancer is demonstrated. The image analysis based on fluorescence intensity variation reveals the characteristics of translocation of nanodots in dense mediums such as tumor models.image
  • Conference Object
    Biopatterning of 3d Cellular Structures Via Contactless Magnetic Manipulation for Drug Screening
    (Mary Ann Liebert, 2023) Önbaş, Rabia; Arslan Yıldız, Ahu
    "Patterning and manipulation techniques have been used to fabricate 3D cell cultures in tissue engineering. The contactless magnetic manipulation approach is a rapid, simple, and cost-effective method that requires paramagnetic agents [1-3] or magnetic materials [4]. Here, to obtain patterned 3D cellular structures a new alginate-based bio-ink formulation was developed to fabricate 3D cellular structures using contactless magnetic manipulation. 3D cardiac model was obtained by patterning rat cardiomyocytes. Cellular and extracellular components and cardiac-specific markers of patterned 3D cellular structures were indicated successfully. Drug response of patterned 3D cellular structures was evaluated by applying doxorubicin. Patterned 3D cardiac cellular structures showed significantly different drug response compared to conventional 2D cell cultures. In conclusion, this technique provides an easy, efficient, and low-cost methodology to fabricate 3D cardiac structures for drug screening.
  • Article
    Citation - WoS: 9
    Citation - Scopus: 9
    Fabrication and Development of a Microfluidic Paper-Based Immunosorbent Assay Platform (μpisa) for Colorimetric Detection of Hepatitis C
    (Royal Society of Chemistry, 2023) Özefe, Fatih; Arslan Yıldız, Ahu
    Paper-based microfluidics is an emerging analysis tool used in various applications, especially in point-of-care (PoC) diagnostic applications, due to its advantages over other types of microfluidic devices in terms of simplicity in both production and operation, cost-effectiveness, rapid response time, low sample consumption, biocompatibility, and ease of disposal. Recently, various techniques have been developed and utilized for the fabrication of paper-based microfluidics, such as photolithography, micro-embossing, wax and PDMS printing, etc. In this study, we offer a fabrication methodology for a microfluidic paper-based immunosorbent assay (μPISA) platform and the detection of Hepatitis C Virus (HCV) was carried out to validate this platform. A laser ablation technique was utilized to form hydrophobic barriers easily and rapidly, which was the major advantage of the developed fabrication methodology. The characterization of the μPISA platform was performed in terms of micro-channel properties using bright-field (BF) microscopy, and surface properties using scanning electron microscopy (SEM). At the same time, sample volume and liquid handling capacity were analyzed quantitatively. Ablation speed (S) and laser power (P) were optimized, and it was shown that one combination (10P60S) provided minimal deviation in micro-channel dimensions and prevented deterioration of hydrophobic barriers. Also, the minimum hydrophobic barrier width, which prevents cross-barrier bleeding, was determined to be 255.92 ± 10.01 μm. Furthermore, colorimetric HCV NS3 detection was implemented to optimize and validate the μPISA platform. Here, HCV NS3 in both PBS and human blood plasma was successfully detected by the naked eye at concentrations as low as 1 ng mL−1 and 10 ng mL−1, respectively. Moreover, the limit of detection (LoD) values for HCV NS3 were acquired as 0.796 ng mL−1 in PBS and 2.203 ng mL−1 in human blood plasma with a turnaround time of 90 min. In comparison with conventional ELISA, highly sensitive and rapid HCV NS3 detection was accomplished colorimetrically on the developed μPISA platform.
  • Article
    Citation - WoS: 17
    Citation - Scopus: 18
    Development of a Hydrocolloid Bio-Ink for 3d Bioprinting
    (Royal Society of Chemistry, 2022) Yıldırım, Özüm; Arslan Yıldız, Ahu
    A new generation of bio-inks that are soft, viscous enough, stable in cell culture, and printable at low printing pressures is required in the current state of 3D bioprinting technology. Hydrogels can meet these features and can mimic the microenvironment of soft tissues easily. Hydrocolloids are a group of hydrogels which have a suitable gelling capacity and rheological properties. According to the literature, polysaccharide-based hydrocolloids are used in the food industry, wound healing technologies, and tissue engineering. Quince seed hydrocolloids (QSHs), which consist of mostly glucuronoxylan, can easily be obtained from quince seeds by water extraction. In this study, the use of a QSH as a bio-ink was investigated. The suitability of QSH for the printing process was assessed by rheological, uniformity and pore factor analyses. Appropriate printing parameters were determined and the characterization of the bioprinted QSHs was performed by SEM analysis, water uptake capacity measurement, and protein adsorption assay. The bioprinted QSHs had excellent water uptake capacity and showed suitable protein adsorption behaviour. Analyses of the biocompatibility and cellular viability of bioprinted QSHs were conducted using NIH-3T3 fibroblast cells and the results were found to be high during short and long-term cell culture periods. It was proved that QSH is a highly promising bio-ink for 3D bioprinting and further tissue engineering applications.
  • Conference Object
    On-Chip 3d Cell Culture Platform for Tumor Modeling and Drug Screening
    (Mary Ann Liebert, 2022) Yıldırım, Özüm; Arslan Yıldız, Ahu
    Three-dimensional (3D) cell culture allows cell-cell and cellmatrix interactions and provides more in vivo like models rather than 2D cell culture which cannot fully mimic native tissue. 3D cell culture on microfluidics allows formation of 3D structures that mimic the physiological and chemical microenvironment for cells[1]. These microfluidic platforms also downsize bench-top laboratory to a microchip, require miniaturized reagent, and are convenient for dynamic drug screening[2]. In this study, a microfluidic platform was designed which is housing a PLLCL scaffold fabricated by electrospinning methodology.
  • Conference Object
    Biofabrication by Magnetic Levitational Assembly of Cells Into Defined 3d Cellular Structures
    (Mary Ann Liebert, 2022) Arslan Yıldız, Ahu
    In the field of tissue engineering 3D (three dimensional) cell culture studies have increased over the years since they are the closest models of real tissues. Compared to the 2D models, there is a big improvement on cell growth, morphology, differentiation, gene and protein expression when 3D system is utilized. Because of these advantages 3D cell culture is commonly used for tissue engineering, artificial organ technologies, regenerative medicine, drug development, drug screening and stem cell studies. Despite promising advances in these areas, there are still unmet needs to completely fulfill all requirements. Sophisticated tools, methodologies and materials are still required for further development in tissue engineering; especially for cellular assembly, single cell level control, easy control over biofabrication system, direct forward cellular imaging and analysis. Recently, magnetic levitation technology that overcomes most of the above mentioned problems, has been utilized for the formation of 3D cellular structures. Magnetic levitational assembly of cells provide rapid, simple, cost-effective 3D cell culture formation while ensuring scaffold-free microenvironment.
  • Conference Object
    Development of New Generation Hydrocolloid Bio-Ink for 3d Bioprinting
    (Mary Ann Liebert, 2022) Arslan Yıldız, Ahu
    Bioprinting enables the production of 3-dimensional (3D) structures by combining bioinks, living cells, extracellular matrix (ECM) components, biochemical factors, proteins, drugs; and it has recently become one of the most promising techniques in the field of tissue engineering. The successful production of the 3D structure to be created by 3D bioprinting technology depends on the properties of the bio-ink to be used. Hydrogel/hydrocolloid materials used as bio-inks are developed using synthetic and natural polymers where they have the necessary rheological properties for printing, they also have biocompatibility, low toxicity and support for cell attachment. Natural hydrogels, which have the ability to mimic the extracellular matrix structure and function at a high rate, are highly preferred bioink materials for bioprinting applications.
  • Conference Object
    Development of 3d Cardiac Models Via Magnetic Manipulation for Drug Screening Studies
    (Mary Ann Liebert, 2022) Önbaş, Rabia; Arslan Yıldız, Ahu
    Drug discovery and development process comprise of preclinical and clinical phases that are very intensive, long, and expensive research phases. However, drug candidates can fail in clinical trials. Toxicity is the major reason that leads to about 30% of drug development failures. Recently, the withdrawal rate of drugs from the market was increased to 33.3%from5.1%due to cardiotoxicity. When the drug fails at phase I, the reasons are probably related to 2-dimensional (2D) cell culture studies that do not represent the real tissue physiology; therefore, they provide misdirected data about the efficacy and toxicity of drug.
  • Conference Object
    Immobilized Gold Nanoparticle Based Plasmonic Assay Platform for Biomolecule and Microorganism Detection
    (Wiley, 2021) Sözmen, Alper Baran; Arslan Yıldız, Ahu
    Plasmonic sensors are suitable tools for study of molecular interactions. Localized Surface Plasmon Resonance (LSPR) based sensors detect spectral changes associated with intramolecular interactions between analyte molecules and recognition elements. Due to its label­free and highly sensitive features, LSPR based methods have high potential for biosensing applications. In this study, we aim to develop a sensitive, label­free, rapid and simple biosensing platform. For this purpose, a novel refractive index (RI) sensitivity enhancement methodology is proposed by immobilizing gold nanoparticles (GNPs) for platform­based LSPR. Fabrication of platform was carried out by GNP synthesis, immobilization of GNPs on polystyrene solid support, and growth of GNPs. Validation of response to RI changes of developed sensor platform was carried out by tests with varying concentrations of sucrose and ethanol. Then as a proof­of­concept, detection ability and detection limit determination of E.coli BL21 (DE3) and protein Bovine Serum Albumin (BSA) was carried out. Adsorption of E.coli BL21 (DE3) via bulk interactions showed that the developed LSPR platform exhibit high enough binding affinity for bacteria detection, and was able to detect down to concentrations as low as 102 CFU/ml. Immune capturing of BSA via anti­BSA antibody showed that the developed LSPR platform was able to detect BSA protein–antibody interaction down to 10 µM concentration range.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 11
    Cost-Effective and Rapid Prototyping of Pmma Microfluidic Device Via Polymer-Assisted Bonding
    (Springer, 2021) Sözmen, Alper Baran; Arslan Yıldız, Ahu
    Microfluidic systems are relatively new technology field with a constant need of novel and practical manufacturing materials and methods. One of the main shortcomings of current methods is the inability to provide rapid bonding, with high bonding strength, and sound microchannel integrity. Herein we propose a novel method of assembly that overcomes the mentioned limitations. Polymer-assisted bonding is a novel, rapid, simple, and inexpensive method where a polymer is solubilized in a solvent and the constituted solution is used as a bonding agent. In this study, we combined this method with utilization of several phase-changing materials (PCMs) as channel-protective agents. Glauber's salt appeared to be more suitable as a channel-protective agent compared to rest of the salts that have been used in this study. Based on the bonding strength, quality analyses, leakage tests, and SEM imaging, the superior assisting bonding solvent was determined to be dichloromethane with a PMMA concentration of 2.5% (W/V). It showed a bonding strength of 23.794 MPa and a nearly non-visible bonding layer formation of 2.83 mu m in width which is proved by SEM imaging. The said combination of PCM, solvent, and polymer concentration also showed success in leakage tests and an application of micro-droplet generator fabrication. The application was carried out to test the applicability of developed prototyping methodology, which resulted in conclusive outcomes as the droplet generator simulation run in COMSOL Multiphysics version 5.1 software. In conclusion, the developed fabrication method promises simple, rapid, and strong bonding with sharp and clear micro-channel engraving.