04. Mühendislik Fakültesi / Faculty of Engineering

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Citation - WoS: 10
Citation - Scopus: 14
3D Bioprinting of mouse pre-osteoblasts and human MSCs using bioinks consisting of gelatin and decellularized bone particles
(Iop Publishing Ltd, 2024) Kara, Aylin; Distler, Thomas; Akkineni, Ashwini Rahul; Tihminlioglu, Funda; Gelinsky, Michael; Boccaccini, Aldo R.; 03.02. Department of Chemical Engineering; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
One of the key challenges in biofabrication applications is to obtain bioinks that provide a balance between printability, shape fidelity, cell viability, and tissue maturation. Decellularization methods allow the extraction of natural extracellular matrix, preserving tissue-specific matrix proteins. However, the critical challenge in bone decellularization is to preserve both organic (collagen, proteoglycans) and inorganic components (hydroxyapatite) to maintain the natural composition and functionality of bone. Besides, there is a need to investigate the effects of decellularized bone (DB) particles as a tissue-based additive in bioink formulation to develop functional bioinks. Here we evaluated the effect of incorporating DB particles of different sizes (<= 45 and <= 100 mu m) and concentrations (1%, 5%, 10% (wt %)) into bioink formulations containing gelatin (GEL) and pre-osteoblasts (MC3T3-E1) or human mesenchymal stem cells (hTERT-MSCs). In addition, we propose a minimalistic bioink formulation using GEL, DB particles and cells with an easy preparation process resulting in a high cell viability. The printability properties of the inks were evaluated. Additionally, rheological properties were determined with shear thinning and thixotropy tests. The bioprinted constructs were cultured for 28 days. The viability, proliferation, and osteogenic differentiation capacity of cells were evaluated using biochemical assays and fluorescence microscopy. The incorporation of DB particles enhanced cell proliferation and osteogenic differentiation capacity which might be due to the natural collagen and hydroxyapatite content of DB particles. Alkaline phosphatase activity is increased significantly by using DB particles, notably, without an osteogenic induction of the cells. Moreover, fluorescence images display pronounced cell-material interaction and cell attachment inside the constructs. With these promising results, the present minimalistic bioink formulation is envisioned as a potential candidate for bone tissue engineering as a clinically translatable material with straightforward preparation and high cell activity.
Citation - WoS: 47
Citation - Scopus: 54
3d Printed Gelatin/Decellularized Bone Composite Scaffolds for Bone Tissue Engineering: Fabrication, Characterization and Cytocompatibility Study
(Elsevier, 2022-06) Kara, Aylin; Distler, Thomas; Polley, Christian; Schneidereit, Dominik; Seitz, Hermann; Friedrich, Oliver; Tıhmınlıoğlu, Funda; Boccaccini, Aldo R; 03.02. Department of Chemical Engineering; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Three-dimensional (3D) printing technology enables the design of personalized scaffolds with tunable pore size and composition. Combining decellularization and 3D printing techniques provides the opportunity to fabricate scaffolds with high potential to mimic native tissue. The aim of this study is to produce novel decellularized bone extracellular matrix (dbECM)-reinforced composite-scaffold that can be used as a biomaterial for bone tissue engineering. Decellularized bone particles (dbPTs, ∼100 μm diameter) were obtained from rabbit femur and used as a reinforcement agent by mixing with gelatin (GEL) in different concentrations. 3D scaffolds were fabricated by using an extrusion-based bioprinter and crosslinking with microbial transglutaminase (mTG) enzyme, followed by freeze-drying to obtain porous structures. Fabricated 3D scaffolds were characterized morphologically, mechanically, and chemically. Furthermore, MC3T3-E1 mouse pre-osteoblast cells were seeded on the dbPTs reinforced GEL scaffolds (GEL/dbPTs) and cultured for 21 days to assess cytocompatibility and cell attachment. We demonstrate the 3D-printability of dbPTs-reinforced GEL hydrogels and the achievement of homogenous distribution of the dbPTs in the whole scaffold structure, as well as bioactivity and cytocompatibility of GEL/dbPTs scaffolds. It was shown that Young's modulus and degradation rate of scaffolds were enhanced with increasing dbPTs content. Multiphoton microscopy imaging displayed the interaction of cells with dbPTs, indicating attachment and proliferation of cells around the particles as well as into the GEL-particle hydrogels. Our results demonstrate that GEL/dbPTs hydrogel formulations have potential for bone tissue engineering.
3d Printing-Assisted Fabrication of Microfluidic Pneumatic Valves
(IEEE, 2023) Keleş, Şeyda; Karakuzu, Betül; Tekin, Hüseyin Cumhur; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Pneumatic valves have a crucial place in the fluidic control in microfluidic systems. Pneumatic valves containing polydimethylsiloxane (PDMS) membrane structures are used in microfluidic systems such as cell separation, and cell manipulation due to their flexible structure, and ease of production. This study demonstrates the rapid and straightforward fabrication of pneumatic valve structures using PDMS membranes, achieved through the utilization of 3D-printed molds. As a result of our experiments, we observed valve closure in a fluidic channel with a height of 150 μm. This closure was achieved by utilizing 400 μm × 800 μm PDMS membrane with a thickness of 66 μm positioned between the fluidic and control channels, while applying 1.5 bar of pressure to the control channel. When the pressure is removed, the opening time of the valve is only 0.02 s, and this response time allows rapid valving function. The presented valve fabrication strategy would allow easy and low-cost production of sophisticated microfluidic chips. © 2023 IEEE.
Citation - WoS: 7
Citation - Scopus: 8
Absorbance-Based Detection of Arsenic in a Microfluidic System With Push-And Pumping
(Elsevier, 2021) Karakuzu, Betül; Gülmez, Yekta; Tekin, H. Cumhur; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Rapid and portable analysis of arsenic (As) contamination in drinking water is very important due to its adverse health effects on humans. Available commercial detection kits have shown low sensitivity and selectivity in analysis, and also they can generate harmful by-products. Microfluidic-based approaches allow portable analysis with gold nanoparticles (AuNPs) as labels. However, they need complex surface modification steps that complicate detection protocols. Due to the lack of precise sensing and affordable solution, we focused on developing a microfluidic platform that uses a push-and-pull pumping method for sensitive detection of As. In this detection principle, a sample is introduced in the microfluidic channel modified with -SH functional groups where As can bind. Then, AuNPs are given in the channel and AuNPs bind on free -SH functional groups which are not allocated with As. Absorbance measurements are conducted to detect AuNPs absorbed on the surfaces and the resulting absorbance value is inversely proportional with As concentration. The method enables detection of As down to 2.2 mu g/L concentration levels in drinking water, which is well-below the allowed maximum As concentration of 10 mu g/L in the drinking waters by the World Health Organization (WHO). The paper reveals that multiple push-and-pull pumping of fixed volume of sample and AuNPs with a syringe pump can improve the binding efficiency in the microfluidic channel. With this technique, low amounts of sample (1 mL) and short total assay time (25 min) are sufficient to detect As.
Citation - WoS: 3
Citation - Scopus: 3
Active Mixing Strategy With Electromechanical Platform for Lab-On Applications
(Institute of Electrical and Electronics Engineers Inc., 2019) Karakuzu, Betül; Özçivici, Engin; Tekin, Hüseyin Cumhur; Tarım, E. Alperay; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The main purpose of this study is to present a new active mixing strategy that can be used for lab-on-A-chip applications to shorten analysis time. An electromechanical platform composed of stepper and DC motors is designed and manufactured. This platform allows rapid mixing in microwells of a polydimethylsiloxane chip for analysis. Mixing in microwells is performed with a stirring bar spun automatically using the electromechanical platform. Mixing experiments performed at different spinning speeds and different time intervals on the platform. It was observed that mixing was achieved only in 300 ms inside 100 ?L microwell using 4300 revolutions per minute (rpm) spinning speeds. Hence, the proposed mixing strategy showed 200-fold faster mixing than pure diffusion-based mixing. © 2019 IEEE.
Citation - WoS: 16
Citation - Scopus: 21
Adhesive Bonding Strategies To Fabricate High-Strength and Transparent 3d Printed Microfluidic Device
(American Institute of Physics, 2020) Keçili, Seren; Tekin, Hüseyin Cumhur; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Recently, the use of 3D printing technologies has become prevalent in microfluidic applications. Although these technologies enable low-cost, rapid, and easy fabrication of microfluidic devices, fabricated devices suffer from optical opaqueness that inhibits their use for microscopic imaging. This study investigates bonding strategies using polydimethylsiloxane (PDMS) and printer resin as interlayer materials to fabricate high-strength optically transparent 3D-printed microfluidic devices. First, we fabricated microfluidic structures using a stereolithography 3D printer. We placed 3D-printed structures on interlayer materials coated surfaces. Then, we either let these 3D-printed structures rest on the coated slides or transferred them to new glass slides. We achieved bonding between 3D-printed structures and glass substrates with UV exposure for resin and with elevated temperature for PDMS interlayer materials. Bonding strength was investigated for different interlayer material thicknesses. We also analyzed the bright-field and fluorescence imaging capability of microfluidic devices fabricated using different bonding strategies. We achieve up to twofold (9.1 bar) improved bonding strength and comparable fluorescence sensitivity with respect to microfluidic devices fabricated using the traditional plasma activated PDMS-glass bonding method. Although stereolithography 3D printer allows fabrication of enclosed channels having dimensions down to similar to 600 mu m, monolithic transparent microfluidic channels with 280 x 110 mu m(2) cross section can be realized using adhesive interlayers. Furthermore, 3D-printed microfluidic chips can be integrated successfully with Protein-G modified substrates using resin interlayers for detection of fluorescent-labeled immunoglobulin down to similar to 30 ng/ml. Hence, this strategy can be applied to fabricate high-strength and transparent microfluidic chips for various optical imaging applications including biosensing.
Citation - WoS: 7
Citation - Scopus: 10
Adjuvant Potency of Astragaloside Vii Embedded Cholesterol Nanoparticles for H3n2 Influenza Vaccine
(TÜBİTAK, 2020) Genç, Rukan; Yakuboğulları, Nilgün; Nalbantsoy, Ayşe; Coven, Fethiye; Bedir, Erdal; 01.01. Units Affiliated to the Rectorate; 03.01. Department of Bioengineering; 01. Izmir Institute of Technology; 03. Faculty of Engineering
Adjuvants are substances that increase the immune response to a given antigen. In the development of novel vaccine adjuvants/systems, saponins are one of the most attractive molecules due to their altered immunomodulatory activities. In this study, we tried to develop PEG (polyethylene glycol)/cholesterol-based lipid nanoparticles (LNPs) to deliver the Astragaloside VII (AST-VII) and potentiate adjuvant properties of AST-VII for the influenza vaccine. In the formation of PEG/cholesterol/AST-VII-based LNPs (PEG300: Chol-AST-VII LNPs), 3 different primary solvents (acetone, ethanol, and chloroform) were evaluated, employing their effects on hydrodynamic particle size, distribution, surface chemistry, and colloidal stability. Prepared nanoparticles were simply admixtured with inactivated influenza antigen (H3N2) and applied to PMA (phorbol 12-myristate 13-acetate)-ionomycin treated human whole blood to evaluate their cytokine release profile. PEG300: Chol-AST-VII LNPs (80.2 +/- 7.7 nm) were obtained using chloroform as a desolvation agent. Co-treatment of PMA-ionomycin with AST-VII and PEG300: Chol-AST-VII LNPs significantly increased the levels of IL-2 and IFN-gamma, compared to PMA-ionomycin alone. In the presence of H3N2, AST-VII was able to augment IL-17A, while PEG300: Chol-AST-VII LNPs stimulated the production of IFN-gamma. Hemolysis was only observed in PEG300: Chol-AST-VII LNPs (250 mu g/mL) treatment. AST-VII and AST-VII-integrated LNPs could be used as efficacious adjuvants for an inactivated H3N2 vaccine in vitro, and cytokine response through Th1/Th17 route was reported.
Akt Inhibitor Arq 092 and Sorafenib Additively Inhibit Progression of Hepatocellular Carcinoma and Improve Immune System in Cirrhotic Rat Model
(Elsevier, 2017) Jilkova, Z. M.; Zeybek Kuyucu, Ayça; Kurma, K.; Pour, S. T. A.; Roth, G. S.; Abbadessa, G.; Decaens, T.; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Background and Aims: Hepatocellular carcinoma (HCC) is often diagnosed at advanced stages with limited number of therapeutic options. Longer exposure to classical treatment of advanced HCC, sorafenib, often over-activates AKT pathway, leading to HCC resistance. Moreover, AKT pathway itself is activated in almost half of HCC cases. Therefore, we investigated the efficacy of combination of Sorafenib with allosteric Akt inhibitor ARQ 092 in a DEN-induced cirrhotic rat model with HCC.
Citation - WoS: 3
Citation - Scopus: 4
Applicability of Low-Intensity Vibrations as a Regulatory Factor on Stem and Progenitor Cell Populations
(Bentham Science Publishers, 2020) Baskan, Öznur; Karadaş, Özge; Meşe, Gülistan; Özçivici, Engin; 03.01. Department of Bioengineering; 01. Izmir Institute of Technology; 04.03. Department of Molecular Biology and Genetics; 03. Faculty of Engineering; 04. Faculty of Science
Persistent and transient mechanical loads can act as biological signals on all levels of an organism. It is therefore not surprising that most cell types can sense and respond to mechanical loads, similar to their interaction with biochemical and electrical signals. The presence or absence of mechanical forces can be an important determinant of form, function and health of many tissue types. Along with naturally occurring mechanical loads, it is possible to manipulate and apply external physical loads on tissues in biomedical sciences, either for prevention or treatment of catabolism related to many factors, including aging, paralysis, sedentary lifestyles and spaceflight. Mechanical loads consist of many components in their applied signal form such as magnitude, frequency, duration and intervals. Even though high magnitude mechanical loads with low frequencies (e.g. running or weight lifting) induce anabolism in musculoskeletal tissues, their applicability as anabolic agents is limited because of the required compliance and physical health of the target population. On the other hand, it is possible to use low magnitude and high frequency (e.g. in a vibratory form) mechanical loads for anabolism as well. Cells, including stem cells of the musculoskeletal tissue, are sensitive to high frequency, low-intensity mechanical signals. This sensitivity can be utilized not only for the targeted treatment of tissues, but also for stem cell expansion, differentiation and biomaterial interaction in tissue engineering applications. In this review, we reported recent advances in the application of low-intensity vibrations on stem and progenitor cell populations. Modulation of cellular behavior with low-intensity vibrations as an alternative or complementary factor to biochemical and scaffold induced signals may represent an increase of capabilities in studies related to tissue engineering.
Citation - WoS: 8
Citation - Scopus: 11
Application of Low Intensity Mechanical Vibrations for Bone Tissue Maintenance and Regeneration
(TÜBİTAK, 2016) Ölçüm, Melis; Baskan, Öznur; Karadaş, Özge; Özçivici, Engin; 03.01. Department of Bioengineering; 01. Izmir Institute of Technology; 03. Faculty of Engineering
Physical exercise is beneficial for bone tissue health, yet its usage is limited for preventing osteoporosis. Even though natural for the bone tissue from development to homeostasis, mechanical loads present with a multitude of physical parameters, including amplitude, duration, frequency, and distribution. Utilizing the most beneficial parameters of mechanical loads may potentiate a nonpharmaceutical tool for biotechnology to prevent and treat bone loss related to aging, bedrest, sedentary lifestyles, weightlessness, and other diseases. Low intensity vibrations (LIVs) consist of mechanical loads with amplitudes smaller than loads prescribed by habitual activity, with a higher frequency. In this review, literature covering LIV signal application on bone tissue and cellular and molecular level is presented. Studies indicate that LIV signals are safe, anabolic, and anticatabolic for skeletal tissue and are of great significance in regenerative medicine applications.
Citation - WoS: 4
Citation - Scopus: 5
Application of Magnetic Levitation Induced Weightlessness To Detect Cell Lineage
(IEEE, 2019) Sarıgil, Öykü; Anıl İnevi, Müge; Yılmaz, Esra; Çağan, Melike; Meşe, Gülistan; Tekin, Hüseyin Cumhur; Özçivici, Engin; 03.01. Department of Bioengineering; 01. Izmir Institute of Technology; 04.03. Department of Molecular Biology and Genetics; 03. Faculty of Engineering; 04. Faculty of Science
Identification and classification of bone marrow cells is an important step for molecular biology and therapeutic studies related to bone marrow disorders such as osteoporosis or obesity. In this study, we applied magnetic levitation technology to induce a weightlessness environment to detect adipocytes and osteoblasts based on their single cell density. This biotechnological method can be used for separation of heterogeneous populations such as bone marrow once adapted to a continuous microfluidic platform.
Citation - WoS: 5
Citation - Scopus: 6
Ascorbic Acid Enhances the Metabolic Activity, Growth and Collagen Production of Human Dermal Fibroblasts Growing in Three-Dimensional (3D) Culture
(Gazi Üniversitesi, 2023) Dikici, Serkan; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Tissue engineering (TE) enables the development of functional synthetic substitutes to be replaced with damaged tissues and organs instead of the use of auto or allografts. A wide range of biomaterials is currently in use as TE scaffolds. Among these materials, naturally sourced ones are favorable due to being highly biocompatible and supporting cell growth and function, whereas synthetic ones are advantageous because of the high tunability on mechanical and physical properties as well as being easy to process. Alongside the advantages of synthetic polymers, they mostly show hydrophobic behavior that limits biomaterial-cell interaction and, consequently, the functioning of the developed TE constructs. In this study, we assessed the impact of L-Ascorbic acid 2-phosphate (AA2P) on improving the culture conditions of human dermal fibroblasts (HDFs) growing on a three-dimensional (3D) scaffold made of polycaprolactone (PCL) using emulsion templating. Our results demonstrated that AA2P enhances the metabolic activity and growth of HDFs as well as collagen deposition by them when supplemented in their growth medium at 50 µg/mL concentration. It showed a great potential to be used as a growth medium supplement to circumvent the disadvantages of culturing human cells on a synthetic biomaterial that is not favored in default. AA2P's potential to improve cell growth and collagen deposition may prove an effective way to culture human cells on 3D PCL PolyHIPE scaffolds for various TE applications.
Assessment of Cell Cycle and Viability of Magnetic Levitation Assembled Cellular Structures
(IEEE, 2020) Anıl İnevi, Müge; Ünal, Yağmur Ceren; Yaman, Sena; Tekin, H. Cumhur; Meşe, Gülistan; Meşe, Gülistan; 03.01. Department of Bioengineering; 01. Izmir Institute of Technology; 04.03. Department of Molecular Biology and Genetics; 03. Faculty of Engineering; 04. Faculty of Science
Label-free magnetic levitation is one of the most recent Earth-based in vitro techniques that simulate the microgravity. This technique offers a great opportunity to biofabricate scaffold-free 3-dimensional (3D) structures and to study the effects of microgravity on these structures. In this study, self-assembled 3D living structures were fabricated in a paramagnetic medium by magnetic levitation technique and effects of the technique on cellular health was assessed. This magnetic force-assisted assembly system applied here offers broad applications in several fields, such as space biotechnology and bottom-up tissue engineering.
Citation - WoS: 7
Citation - Scopus: 7
Assessment of Cholesterol-Derived Ionic Copolymers as Potential Vectors for Gene Delivery
(American Chemical Society, 2013-11) Sevimli, Sema; Sagnella, Sharon; Kavallaris, Maria; Bulmuş, Volga; Davis, Thomas P.; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
A library of cholesterol-derived ionic copolymers were previously synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization as 'smart' gene delivery vehicles that hold diverse surface charges. Polyplex systems formed with anionic poly(methacrylic acid-co-cholesteryl methacrylate) (P(MAA-co-CMA)) and cationic poly(dimethylamino ethyl methacrylate-co-cholesteryl methacrylate) (Q-P(DMAEMA-co-CMA)) copolymer series were evaluated for their therapeutic efficiency. Cell viability assays, conducted on SHEP, HepG2, H460, and MRC5 cell lines, revealed that alterations in the copolymer composition (CMA mol %) affected the cytotoxicity profile. Increasing the number of cholesterol moieties in Q-P(DMAEMA-co-CMA) copolymers reduced the overall toxicity (in H460 and HepG2 cells) while P(MAA-co-CMA) series displayed no significant toxicity regardless of the CMA content. Agarose gel electrophoresis was employed to investigate the formation of stable polyplexes and determine their complete conjugation ratios. P(MAA-co-CMA) copolymer series were conjugated to DNA through a cationic linker, oligolysine, while Q-P(DMAEMA-co-CMA)-siRNA complexes were readily formed via electrostatic interactions at conjugation ratios beginning from 6:1:1 (oligolysine-P(MAA-co-CMA)-DNA) and 20:1 (Q-P(DMAEMA-co-CMA)-siRNA), respectively. The hydrodynamic diameter, ζ potential and complex stability of the polyplexes were evaluated in accordance to complexation ratios and copolymer composition by dynamic light scattering (DLS). The therapeutic efficiency of the conjugates was assessed in SHEP cells via transfection and imaging assays using RT-qPCR, Western blotting, flow cytometry, and confocal microscopy. DNA transfection studies revealed P(MAA-co-CMA)-oligolysine-DNA ternary complexes to be ineffective transfection vehicles that mostly adhere to the cell surface as opposed to internalizing and partaking in endosomal disrupting activity. The transfection efficiency of Q-P(DMAEMA-co-CMA)-GFP siRNA complexes were found to be polymer composition and N/P ratio dependent, with Q-2% CMA-GFP siRNA polyplexes at N/P ratio 20:1 showing the highest gene suppression in GFP expressing SHEP cells. Cellular internalization studies suggested that Q-P(DMAEMA-co-CMA)-siRNA conjugates efficiently escaped the endolysosomal pathway and released siRNA into the cytoplasm. The gene delivery profile, reported herein, illuminates the positive and negative attributes of each therapeutic design and strongly suggests Q-P(DMAEMA-co-CMA)-siRNA particles are extremely promising candidates for in vivo applications of siRNA therapy.
Astragalus sp.
(CRC Press, 2023) Yakuboğulları, Nilgün; Bedir, Erdal; 01.01. Units Affiliated to the Rectorate; 03.01. Department of Bioengineering; 01. Izmir Institute of Technology; 03. Faculty of Engineering
Astragalus is one of the largest genera in Turkey and is widely distributed worldwide. The phytochemical studies on Turkish Astragalus species have presented 112 new compounds besides 63 known compounds. The overriding basis for biological activity studies is the traditional use of Astragalus roots in the Southeastern Region of Turkey to cure leukemia. As the isolated compounds did not show cytotoxic properties, a hypothesis that the biological activity of Astragalus saponins might result from the activation of the immune system came up. While Astragalus polysaccharides are used for their strong immunomodulatory activities in Chinese medicine, there are a few articles revealing the immunostimulatory properties of Astragalus saponins. Here, we summarized the compounds isolated from Turkish Astragalus species and concentrated on the immunomodulatory activities of these compounds to put forward their potential as saponin-based vaccine adjuvants. © 2024 selection and editorial matter, Ufuk Koca-Caliskan; individual chapters, the contributors.
Astragalus Trojanus Stev. Batch Cultures: Cycloartane-Type Metabolite Accumulation in Response To Ph, Sucrose and Casein Hydrolysate
(Hacettepe Üniversitesi, 2019) Nartop, Pınar; Gürel, Aynur; Akgün, İsmail Hakkı; Bedir, Erdal; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
I n this study, two grams of callus regenerated from stem and leaf explants of Astragalus trojanus Stev. were cultured in Woody Plant Medium (WPM) supplemented with 1 mg/L 2,4-D for four weeks and used as inoculum in order to investigate the effects of working volume and media composition. The highest biomass was obtained in 250 mL flask with astragaloside IV (1.66 µg/mg) and cycloastragenol (0.19 µg/mg) accumulation. Different concentrations of sucrose and casein hydrolysate (1 and 2 g/L) were also tested and the effect of pH was also investigated. Biomass accumulation cannot be enhanced, however, astragaloside IV and cycloastragenol content was ascended. The highest astragaloside IV (95.23 µg/mg) and cycloastragenol (5.93 mg/mg) accumulations were obtained at pH 6.8 and 2 g/L casein hydrolysate, respectively
Citation - WoS: 14
Citation - Scopus: 15
Bacterial Cellulose Based Facial Mask With Antioxidant Property and High Moisturizing Capacity
(Springer, 2021) Bilgi, Eyüp; Homan Gökçe, Evren; Bayır, Ece; Şendemir, Aylin; Özgen Özer, Kevser; Hames Tuna, Elif Esin; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Bacterial cellulose (BC) produced by certain bacteria has the potential to be used in many different areas. Despite its advantageous properties compared to plant cellulose, such as high purity, mechanical strength, nanofiber mesh structure, and high-water holding capacity, its production through a biotechnological process prevents it from competing with plant counterparts in terms of cost-effectiveness. Therefore, studies have focused on the development of culture media with cost-effective BC production methods and the production of high value-added products from BC. In this study, it was aimed to develop a taurine-loaded moisturizing facial mask with antioxidant properties based on BC's high-water retention and chemical retention capacity. BC facial mask samples were characterized by Scanning Electron Microscopy (SEM) imaging, Fourier Transform Infrared (FTIR) Spectroscopy, Differential Scanning Calorimetry (DSC), Liquid Chromatography-Mass spectrometry (LC-MS), microbial and mechanical stability tests, as well as cytotoxicity tests. According to our results, produced facial mask samples did not show any cytotoxic effect on human keratinocyte (HS2) or mouse fibroblast (L-929) cell lines; it has high thermal stability, which makes it suitable for different sterilization techniques including sterilization by heat treatment. Taurine release (over 2 mu g/mL in 5 min) and microbial stability tests (no bacterial growth observed) of packaged products kept at 40 and 25 degrees C for 6 months have shown that the product preserves its characteristics for a long time. In conclusion bacterial cellulose-based facial masks are suitable for use as a facial mask, and they can be used for moisturizing and antioxidant properties by means of taurine.
Citation - WoS: 15
Citation - Scopus: 17
Bacterial Detection Using Bacteriophages and Gold Nanorods by Following Time-Dependent Changes in Raman Spectral Signals
(Informa Healthcare, 2018) Moghtader, Farzaneh; Tomak, Aysel; Zareie, Hadi M.; Pişkin, Erhan; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
This study attemps to develop bacterial detection strategies using bacteriophages and gold nanorods (GNRs) by Raman spectral analysis. Escherichia coli was selected as the target and its specific phage was used as the bioprobe. Target bacteria and phages were propagated/purified by traditional techniques. GNRs were synthesized by using hexadecyltrimethyl ammonium bromide (CTAB) as stabilizer. A two-step detection strategy was applied: Firstly, the target bacteria were interacted with GNRs in suspensions, and then they were dropped onto silica substrates for detection. It was possible to obtain clear surface-enchanced Raman spectroscopy (SERS) peaks of the target bacteria, even without using phages. In the second step, the phage nanoemulsions were droped onto the bacterial-GNRs complexes on those surfaces and time-dependent changes in the Raman spectra were monitored at different time intervals upto 40 min. These results demonstrated that how one can apply phages with plasmonic nanoparticles for detection of pathogenic bacteria very effectively in a quite simple test.
Citation - WoS: 3
Citation - Scopus: 2
Bacterial Mirobiota and Chemical Properties of Turkish Tarhana
(Slovak University of Agriculture, 2023) Al, Rabia; Yurt, Mediha Nur Zafer; Ersoy Ömeroğlu, Esra; Can, Özge; Temiz, Sevval Nur; Altunbas, Osman; Soyucok, Ali; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Tarhana is one of the traditional Turkish fermented food and it is served as a soup. In this study, bacterial microbiota and chemical properties (acidity, salt, and moisture content) of tarhana samples (n=96) were examined. The metagenomic analysis revealed that Firmicutes were the dominant phylum and Bacillaceae, Enterococcaceae, Paenibacillaceae, Enterobacteriaceae, and Clostridiaceae were the dominant bacterial families. In the samples, Bacillus, Enterococcus, and Paenibacillus were mostly identified at the genus level. Alpha diversity and evenness showed that sample 30 had the highest diversity collected from Izmir. Principal Coordinate Analysis was used to identify relationships of samples at different taxonomic levels and it was found that most of the samples were closely related at the phylum level. Chemical analysis indicated that the acidity of tarhana samples varied between 5.00% and 42.5%, moisture contents were 4.39- 18.66% and salt values were from 0.32% to 6.64%. The results of this study extensively demonstrated the chemical properties and the dominant bacterial communities present in tarhana samples collected from different parts of Turkiye.
Citation - WoS: 34
Citation - Scopus: 40
Batch and Column Studies on Heavy Metal Removal Using a Local Zeolitic Tuff
(Elsevier Ltd., 2010-09) Balköse, Devrim; Ülkü, Semra; Can, Özge; 03.02. Department of Chemical Engineering; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Ion exchange is considered to be one of the most cost effective methods if low cost ion exchangers such as natural zeolites are used in waste water treatment. In this study, a zeolitic tuff rich in clinoptilolite from Gördes Manisa Turkey was examined to evaluate its ion exchange performance for the removal of copper, nickel and cobalt ions from metal (II) nitrate solutions at various concentrations by performing both batch and packed column experiments. A clinoptilolite tuff with purity around 60% was used in ion exchange experiments. Copper, nickel and cobalt exchange capacities of the tuff were determined as 8.3mg (0.26meq) Cu2+/g, 6.6mg (0.23meq) Ni2+/g and 4.5mg (0.15meq) Co2+/g, respectively. The equilibrium behavior of the system was best described by classical Langmuir model. The experimental breakthrough curves from the column experiments were fitted to solid diffusion control model. The study showed that efficient metal ion removal can be done by using the local clinoptilolite rich tuff. © 2010 Elsevier B.V.

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