Bioengineering / Biyomühendislik
Permanent URI for this collectionhttps://hdl.handle.net/11147/4529
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Conference Object A Glucuronoxylan-Based Bio-Ink Development: Characterization and Application(Wiley, 2023) Yıldırım, Ömer; Arslan Yıldız, AhuBioprinting is a trending technique that enables the fabrication of threedimensional (3D) constructs in designed shapes and with desired properties. Bioinks are one of the most significant components of bioprinting and the successful fabrication of 3D bioprinted constructs mostly depends on the features of bioinks that would be used. New generation bioinks that are soft and viscous enough, printable under low pressure, stable in cell culture, and have fast gelation mechanisms are ideal to be used in current bioprinting techniques. Hydrocolloids have said features and have similar properties to native ECM structures. Hence bioinks that are developed from hydrocolloids can be utilized for mimicking of ECM structure of soft tissues. Polysaccharidebased hydrocolloids are ideal bioink candidates with their high waterholding capacity and biocompatibility. Here, a glucuronoxylanbased newgeneration bioink was developed, and its printability was evaluated for 3D bioprinting applications. The glucuronoxylanbased hydrocolloid was obtained by water extraction of quince seeds and its utilization in bioprinting was investigated. Bioink characterization was done by FTIR and mechanical analysis. Bioprinting parameters were optimized assessing uniformity, pore factor, and shape fidelity. Then, the characterization of bioprinted constructs was performed by pore angle measurement, waterholding capacity analysis, protein adsorption, and cell viability assays. Bioprinted structures have high mechanical strength, suitable protein adsorption behavior, and waterholding capacity as high as 20fold of its own weight, which is higher than other hydrogels that were used in soft tissue engineering. Moreover, the cell viability results of fibroblast cells in the bioink were high for longterm culture. In conclusion, findings show that the developed glucuronoxylanbased bioink is a biocompatible and promising bioink material for further tissue engineering applications.Conference Object Biopatterning of 3d Cellular Structures Via Contactless Magnetic Manipulation for Drug Screening(Mary Ann Liebert, 2023) Onbas, Rabia; Arslan Yıldız, AhuArticle Citation - WoS: 1Citation - Scopus: 1The 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 HakanThis 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.imageArticle Citation - WoS: 14Citation - Scopus: 14Development of Tissue-Engineered Vascular Grafts From Decellularized Parsley Stems(Royal Society of Chemistry, 2023) Çevik, Merve; Dikici, SerkanCardiovascular diseases are mostly associated with narrowing or blockage of blood vessels, and it is the most common cause of death worldwide. The use of vascular grafts is a promising approach to bypass or replace the blocked vessels for long-term treatment. Although autologous arteries or veins are the most preferred tissue sources for vascular bypass, the limited presence and poor quality of autologous vessels necessitate seeking alternative biomaterials. Recently, synthetic grafts have gained attention as an alternative to autologous grafts. However, the high failure rate of synthetic grafts has been reported primarily due to thrombosis, atherosclerosis, intimal hyperplasia, or infection. Thrombosis, the main reason for failure upon implantation, is associated with damage or absence of endothelial cell lining in the vascular graft's luminal surface. To overcome this, tissue-engineered vascular grafts (TEVGs) have come into prominence. Alongside the well-established scaffold manufacturing techniques, decellularized plant-based constructs have recently gained significant importance and are an emerging field in tissue engineering and regenerative medicine. Accordingly, in this study, we demonstrated the fabrication of tubular scaffolds from decellularized parsley stems and recellularized them with human endothelial cells to be used as a potential TEVG. Our results suggested that the native plant DNA was successfully removed, and soft tubular biomaterials were successfully manufactured via the chemical decellularization of the parsley stems. The decellularized parsley stems showed suitable mechanical and biological properties to be used as a TEVG material, and they provided a suitable environment for the culture of human endothelial cells to attach and create a pseudo endothelium prior to implantation. This study is the first one to demonstrate the potential of the parsley stems to be used as a potential TEVG biomaterial. © 2024 The Royal Society of Chemistry.Article Citation - WoS: 3Citation - Scopus: 4Biopatterning of 3d Cellular Model by Contactless Magnetic Manipulation for Cardiotoxicity Screening(Mary Ann Liebert, Inc, 2023) Önbaş, Rabia; Arslan Yıldız, AhuPatterning cells to create three-dimensional (3D) cell culture models by magnetic manipulation is a promising technique, which is rapid, simple, and cost-effective. This study introduces a new biopatterning approach based on magnetic manipulation of cells with a bioink that consists alginate, cells, and magnetic nanoparticles. Plackett-Burman and Box-Behnken experimental design models were used to optimize bioink formulation where NIH-3T3 cells were utilized as a model cell line. The patterning capability was confirmed by light microscopy through 7 days culture time. Then, biopatterned 3D cardiac structures were formed using H9c2 cardiomyocyte cells. Cellular and extracellular components, F-actin and collagen Type I, and cardiac-specific biomarkers, Troponin T and MYH6, of biopatterned 3D cardiac structures were observed successfully. Moreover, Doxorubicin (DOX)-induced cardiotoxicity was investigated for developed 3D model, and IC50 value was calculated as 8.1 μM for biopatterned 3D cardiac structures, which showed higher resistance against DOX-exposure compared to conventional two-dimensional cell culture. Hereby, developed biopatterning methodology proved to be a simple and rapid approach to fabricate 3D cardiac models, especially for drug screening applications. Copyright 2023, Mary Ann Liebert, Inc., publishers.Article Citation - WoS: 18Citation - Scopus: 17Modifying Pickering Polymerized High Internal Phase Emulsion Morphology by Adjusting Particle Hydrophilicity(Elsevier, 2024) Durgut, Enes; Zhou, Muchu; Dikici, Betuel Aldemir; Foudazi, Reza; Claeyssens, FrederikThis study investigates the use of submicron polymeric particles with varying crosslinking densities as the sole stabilizer for producing Polymerized High Internal Phase Emulsions (PolyHIPE). We establish a direct correlation between the crosslinking density and the hydrophilicity of the polymer particles. The hydrophilicity of these particles significantly influences the morphology and rheology of HIPEs. These differences manifest as various morphological variations in the resulting PolyHIPE templates. It was discovered that by increasing the crosslinker weight percentage in the particles from 0 % to 100 %, PolyHIPEs with semi-open, open, and closed porous structures can be obtained. Furthermore, non-crosslinked particles were observed to dissolve in the continuous phase, acting as macromolecular surfactants that generate small pores akin to surfactant-stabilized structures in PolyHIPE. These findings offer fresh insights into the relationship between particle localization at the interface, HIPE rheology, and the formation of pore throats in Pickering PolyHIPEs, leading to the creation of either closed or open porous networks. Additionally, interfacial rheological results demonstrate that particles synthesized with varying monomer-to-crosslinker ratios exhibit different interfacial elasticities, which are linked to PolyHIPE morphology.Conference Object Biofabrication of Scaffold-Free 3d Cellular Structures Using Magnetic Levitational Assembly To Study Cardiac Toxicity(Mary Ann Liebert, 2023) Yıldız, Ahu Arslan; Arslan Yıldız, Ahu; Onbaş, RabiaSpheroids are one of the well-characterized 3D cell culture approaches for drug screening and therapeutic studies. Magnetic levitation (MagLev) is a newly developing approach to form 3D cellular structures and spheroids [1,2,3]. Magnetic levitational assembly of cells provides rapid, simple, cost-effective 3D cell culture formation while ensuring scaffold-free microenvironment. Here, our efforts are summarized in designing new magnetic levitation platform and biofabrication of 3D cellular entities via magnetic levitation for tissue engineering. Magnetic levitation and guidance of cells were provided by using a paramagnetic agent to fabricate scaffold-free 3D cellular structures. The parameters of cell density, paramagnetic agent concentration, and culturing time were optimized to obtain 3D cardiac cellular structures with tunable size, circularity, and high cell viability. Cellular and extracellular components of the 3D cellular structures were demonstrated via immunofluorescent staining. Also, 3D cardiac cellular structures showed more resistance to drug exposure compared to 2D control. In conclusion, MagLev methodology offers an easy and efficient way to fabricate 3D cellular structures for drug screening studies.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: 7Citation - Scopus: 8Bioinspired Multi-Layer Biopolymer-Based Dental Implant Coating for Enhanced Osseointegration(Wiley, 2023) Üzülmez, Betül; Demirsoy, Zeynep; Can, Özge; Gülseren, GulcihanThe major drawbacks of metal-based implants are weak osseointegration and post-operational infections. These limitations restrict the long-term use of implants that may cause severe tissue damage and replacement of the implant. Recent strategies to enhance the osseointegration process require an elaborate fabrication process and suffer from post-operative complications. To address the current challenges taking inspiration from the extracellular matrix (ECM), the current study is designed to establish enhanced osseointegration with lowered risk of infection. Natural biopolymer pectin, peptide amphiphiles, and enzyme-mimicking fullerene moieties are governed to present an ECM-like environment around the implant surfaces. This multifunctional approach promotes osseointegration via inducing biomineralization and osteoblast differentiation. Application of the biopolymer-based composite to the metal surfaces significantly enhances cellular attachment, supports the mineral deposition, and upregulates osteoblast-specific gene expression. In addition to the osteoinductive properties of the constructed layers, the inherent antimicrobial properties of multilayer coating are also used to prevent infection possibility. The reported biopolymer-artificial enzyme composite demonstrates antimicrobial activity against Escherichia coli and Bacillus subtilis as a multifunctional surface coating.Article Citation - WoS: 7Citation - Scopus: 7Potent Telomerase Activators From a Novel Sapogenin Via Biotransformation Utilizing Camarosporium Laburnicola, an Endophytic Fungus(BioMed Central Ltd., 2023) Küçüksolak, Melis; Yılmaz, Sinem; Ballar Kırmızıbayrak, Petek; Bedir, ErdalBACKGROUND: Cycloartane-type triterpenoids possess important biological activities, including immunostimulant, wound healing, and telomerase activation. Biotransformation is one of the derivatization strategies of natural products to improve their bioactivities. Endophytic fungi have attracted attention in biotransformation studies because of their ability to perform modifications in complex structures with a high degree of stereospecificity. RESULTS: This study focuses on biotransformation studies on cyclocephagenol (1), a novel cycloartane-type sapogenin from Astragalus species, and its 12-hydroxy derivatives (2 and 3) to obtain new telomerase activators. Since the hTERT protein levels of cyclocephagenol (1) and its 12-hydroxy derivatives (2 and 3) on HEKn cells were found to be notable, biotransformation studies were carried out on cyclocephagenol and its 12-hydroxy derivatives using Camarosporium laburnicola, an endophytic fungus isolated from Astragalus angustifolius. Later, immunoblotting and PCR-based ELISA assay were used to screen starting compounds and biotransformation products for their effects on hTERT protein levels and telomerase activation. All compounds showed improved telomerase activation compared to the control group. CONCLUSIONS: As a result of biotransformation studies, seven new metabolites were obtained and characterized, verifying the potential of C. laburnicola as a biocatalyst. Additionally, the bioactivity results showed that this endophytic biocatalyst is unique in transforming the metabolites of its host to afford potent telomerase activators. © 2023. The Author(s).