Browsing by Author "Sariyar, Ece"

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Citation - WoS: 17
Citation - Scopus: 18
Three-Dimensional Cell Culture Models of Hepatocellular Carcinoma - a Review
(Springer, 2021) Ayvaz, Irmak; Sunay, Dilara; Sariyar, Ece; Erdal, Esra; Karagonlar, Zeynep Firtina
Introduction Three-dimensional (3D) cell culture studies are becoming extremely common because of their capability to mimic tumor architecture, such as cell-cell and cell-ECM interactions, more efficiently than 2D monolayer systems. These interactions have important roles in defining the tumor cell behaviors, such as proliferation, differentiation, and most importantly, tumor drug response. Objective This review aims to provide an overview of the methods for 3D tumor spheroid formation to model human tumors, specifically concentrated on studies using hepatocellular carcinoma (HCC) cells. Method We obtained information from previously published articles. In this review, there is discussion of the scaffold and non-scaffold-based approaches, including hanging drop, bioreactors and 3D bioprinting. Results and Conclusion The mimicking of the tumor microenvironment (TME) as tumor spheroids could provide a valuable platform for studying tumor biology. Multicellular tumor spheroids are self-assembled cultures of mixed cells (tumor and stromal cells) organized in a 3D arrangement. These spheroids closely mimic the main features of human solid tumors, such as structural organization, central hypoxia, and overall oxygen and nutrient gradients. Hepatocellular carcinoma (HCC) is the most common liver malignancy, and most difficult to overcome because of its drug resistance and tumor heterogeneity. In order to mimic this highly heterogeneous environment, 3D cell culture systems are needed.
Citation - WoS: 10
Citation - Scopus: 11
Upconversion Properties of Tm3+-Er3+ Co-Doped Layered Perovskites and In-Vitro Cytotoxicity of Their Exfoliated Nanomaterials
(Elsevier, 2021) Gunay, Bensu; Sariyar, Ece; Unal, Ugur; Karagonlar, Zeynep Firtina; Saglam, Ozge
The upconversion behavior of Er3+/Tm3+ co-doped Ruddlesden-Popper type K(2)Ln(2)Ti(3)O(10) layered perovskites was investigated. The lanthanide pair was selected for achieving 980 nm-driven green, red, and NIR emission. The perovskites having different dopant compositions were synthesized by a conventional solid-state procedure by substitution of La3+ ions in the host lattice. Moreover, the single nanosheets having approximately 1.8 nm thickness and 2 mu m lateral size were obtained via chemical exfoliation. The non-doped and co-doped layered materials and the nanosheets derived from these materials were characterized by X-ray diffraction, Scanning Electron Microscopy, Atomic Force Microscopy and custom-made experimental set-up of upconversion emission spectroscopy. According to the XRD profiles, the perovskites had the layered orientation and water molecules in the interlayer domain because of their hygroscopic nature. The co-doped layered perovskites presented twophoton excited green and red emissions, identified as S-4(3/2) -> (4)I(15/2 )with H-2(11/2) -> (4)I(15/2 )and F-4(9/2) -> I-4(15/2) of the Er3+ transitions with a NIR emission. The intensity of red to green ratio emission of the materials increased with respect to the co-dopant concentration. The nanosheets' upconversion emission was weak in the visible region compared to their layered morphology. On the other hand, the NIR emission based on H-3(4) -> H-3(6) transition of the Tm3+ ions was preserved despite the acid and solvent treatments to break apart the layered orientation. MTT assay and Calcein/PI staining were conducted to evaluate cytotoxicity of non-doped and Er3+/Tm3+ co-doped K(2)Ln(2)Ti(3)O(10) perovskites and their exfoliated nanosheets on HEK 293 and HepG2 cell lines. Both assays indicated that although cell viability decreases with increasing concentration, good cell viability was observed at even 100 mu g/mL. In addition to their excellent luminescent and optical features, the nanomaterials also demonstrated low cytotoxicity increasing the potential for their use in laser-based biological applications.