63 results on '"Ozge Akbulut"'
Search Results
2. Local optimization of low power laser machining of MgO at the green state enables cost- and energy-efficient benchtop fabrication
- Author
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Aleyna Beste Ozhan, Gizem Demir, and Ozge Akbulut
- Subjects
Strategy and Management ,Management Science and Operations Research ,Industrial and Manufacturing Engineering - Published
- 2023
3. Targeting TACC3 represents a novel vulnerability in highly aggressive breast cancers with centrosome amplification
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Ozge Saatci, Ozge Akbulut, Metin Cetin, Vitali Sikirzhytski, Meral Uner, Deniz Lengerli, Elizabeth C. O’Quinn, Martin J. Romeo, Burcu Caliskan, Erden Banoglu, Sercan Aksoy, Aysegul Uner, and Ozgur Sahin
- Subjects
Cell Biology ,Molecular Biology - Abstract
Centrosome amplification (CA) is a hallmark of cancer that is strongly associated with highly aggressive disease and worse clinical outcome. Clustering extra centrosomes is a major coping mechanism required for faithful mitosis of cancer cells with CA that would otherwise undergo mitotic catastrophe and cell death. However, its underlying molecular mechanisms have not been fully described. Furthermore, little is known about the processes and players triggering aggressiveness of cells with CA beyond mitosis. Here, we identified Transforming Acidic Coiled-Coil Containing Protein 3 (TACC3) to be overexpressed in tumors with CA, and its high expression is associated with dramatically worse clinical outcome. We demonstrated, for the first time, that TACC3 forms distinct functional interactomes regulating different processes in mitosis and interphase to ensure proliferation and survival of cancer cells with CA. Mitotic TACC3 interacts with the Kinesin Family Member C1 (KIFC1) to cluster extra centrosomes for mitotic progression, and inhibition of this interaction leads to mitotic cell death via multipolar spindle formation. Interphase TACC3 interacts with the nucleosome remodeling and deacetylase (NuRD) complex (HDAC2 and MBD2) in nucleus to inhibit the expression of key tumor suppressors (e.g., p21, p16 and APAF1) driving G1/S progression, and its inhibition blocks these interactions and causes p53-independent G1 arrest and apoptosis. Notably, inducing CA by p53 loss/mutation increases the expression of TACC3 and KIFC1 via FOXM1 and renders cancer cells highly sensitive to TACC3 inhibition. Targeting TACC3 by guide RNAs or small molecule inhibitors strongly inhibits growth of organoids and breast cancer cell line- and patient-derived xenografts with CA by induction of multipolar spindles, mitotic and G1 arrest. Altogether, our results show that TACC3 is a multifunctional driver of highly aggressive breast tumors with CA and that targeting TACC3 is a promising approach to tackle this disease.
- Published
- 2023
4. Abstract P4-08-20: Inhibition of TACC3 blocks the growth of highly aggressive breast cancers with centrosome amplification
- Author
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Ozge Saatci, Ozge Akbulut, Metin Cetin, Vitali Sikirzhytski, and Ozgur Sahin
- Subjects
Cancer Research ,Oncology - Abstract
Centrosome amplification (CA) is a hallmark of cancer that is strongly associated with highly aggressive disease and worse clinical outcome. Enhanced mitotic progression via clustering of extra centrosomes is a major coping mechanism utilized by cancer cells with CA that would otherwise undergo mitotic cell death due to formation of multipolar spindles. However, the underlying molecular mechanisms have largely been unexplored. Furthermore, mitosis-targeting inhibitors have mostly been unsuccessful in clinical settings with poor efficacy and severe side effects. Therefore, there is a dire need to uncover novel molecular mechanisms of CA-driven tumor growth and identify therapeutic targets playing key roles not only in mitosis, but also in interphase of cancer cells with CA to achieve durable anti-tumor effect with minimal toxicity. Here, we identified Transforming Acidic Coiled-Coil Containing Protein 3 (TACC3) as a novel CA-directed dependency, driving highly aggressive cell growth by forming distinct functional interactomes during cell cycle progression. We demonstrated, for the first time, that TACC3 interacts with the Kinesin Family Member C1 (KIFC1) via its TACC domain in mitotic cells with CA to promote centrosome clustering (CC) and facilitate mitotic progression. On the other hand, TACC3 interacts with the members of the nucleosome remodeling and deacetylase (NuRD) complex (HDAC2 and MBD2) in the nucleus of interphase cells with CA, thereby suppressing the transcription of key tumor suppressors to facilitate G1/S progression and cell survival. Inhibiting TACC3 in mitotic cells blocks the formation of TACC3/KIFC1 complex, leading to formation of multipolar spindles and activation of spindle assembly checkpoint (SAC)/CDK1/p-Bcl2 axis that ultimately results in mitotic cell death; whereas TACC3 inhibition in interphase cells blocks TACC3/HDAC2/MBD2 complex, leading to enhanced transcription of cyclin-dependent kinase inhibitors (e.g., p21 and p16) and apoptosis regulators (e.g., APAF1), ultimately causing p53-independent G1 arrest and strong apoptosis. Notably, inducing CA by chemical (cytochalasin D) or genomic (PLK4 overexpression or p53 loss) modulations renders cancer cells highly sensitive to TACC3 inhibition, showing the dependency of cells with CA to TACC3. Targeting TACC3 by small molecule inhibitors or CrispR-CAS9-mediated knock-out significantly reduces colony formation ability, inhibits the growth of organoids of patient-derived xenografts (PDXs) with CA, and strongly inhibits tumor growth in breast cancer cell line xenografts and PDXs with CA. Notably, we demonstrated that high CA tumors express much higher levels of TACC3, and high TACC3 expression, in association with its downstream effectors, KIFC1, HDAC2 and MBD2, leads to drastically worse clinical outcome in cancer patients with CA. Altogether, our results show, for the first time, that TACC3 is a multifunctional driver of the growth of the highly aggressive breast tumors with CA and that targeting TACC3 is a promising approach to tackle this aggressive disease. Citation Format: Ozge Saatci, Ozge Akbulut, Metin Cetin, Vitali Sikirzhytski, Ozgur Sahin. Inhibition of TACC3 blocks the growth of highly aggressive breast cancers with centrosome amplification [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-08-20.
- Published
- 2023
5. Abstract P6-10-18: Developing novel lysyl oxidase (LOX) inhibitors to overcome chemotherapy resistance in triple negative breast cancer
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Metin Cetin, Ozge Saatci, Ozge Akbulut, Chad Beneker, Abdol-Hossein Rezaeian, Mikhail Chernov, Campbell McInnes, and Ozgur Sahin
- Subjects
Cancer Research ,Oncology - Abstract
Triple negative breast cancer (TNBC) is the most aggressive breast cancer subtype. It accounts for ~15% of all breast cancer patients yet is responsible for 30% of breast cancer deaths. TNBC is treated primarily with conventional chemotherapy; however, resistance to therapy is common, leading to high mortality rates. Importantly, the benefit of current therapeutic strategies used in chemoresistant TNBC, i.e., immunotherapy and antibody-drug conjugates, is confined to only a fraction of patients, and survival benefit is limited. Therefore, there is an urgent need to identify novel and effective treatment strategies to overcome chemoresistance. Recently, we identified hypoxia-induced ECM re-modeler, lysyl oxidase (LOX), a member of LOX family, as a key mediator of chemoresistance in TNBC. However, currently available LOX inhibitors are either non-selective and/or show toxicity. Here, we performed a high-throughput cell-based LOX activity screen (HTS) with more than 5,000 molecules selected from a diversified compound library and identified the bi-thiazole derivatives as novel potent LOX inhibitors. Our structure activity relationship (SAR) analysis resulted in two lead compounds 6403, a relatively LOX-specific inhibitor, and 6415, a more LOX/LOXL2 inhibitor. Both compounds reduced collagen cross-linking (canonical function of LOX) and led to chemosensitization in TNBC cell lines and in chemoresistant TNBC PDX organoids. In addition, 6403 and 6415 reduced the TGF-beta induced fibrosis and inhibited migration capacity of the breast cancer cell lines. Importantly, 6403 showed excellent pharmacokinetic profile and did not lead to any observable toxicity in mice. Notably, 6403 overcame doxorubicin resistance in LOX-expressing 4T1 syngeneic model with no apparent toxicity. Furthermore, our novel LOX and LOX/LOXL2 dual inhibitors show superior inhibition of LOX activity compared to the recently developed and clinically tested LOX family or LOXL2/LOXL3 inhibitors. Overall, we identified novel potent LOX inhibitors with no observable toxicity for further preclinical development and future clinical testing to overcome chemoresistance in TNBC. Citation Format: Metin Cetin, Ozge Saatci, Ozge Akbulut, Chad Beneker, Abdol-Hossein Rezaeian, Mikhail Chernov, Campbell McInnes, Ozgur Sahin. Developing novel lysyl oxidase (LOX) inhibitors to overcome chemotherapy resistance in triple negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-10-18.
- Published
- 2023
6. Data from A Highly Potent TACC3 Inhibitor as a Novel Anticancer Drug Candidate
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Ozgur Sahin, Erden Banoglu, Burcu Caliskan, Aytekin Akyol, Aynur Isik, Urartu O.S. Seker, Elif Duman, Ozge Saatci, Deniz Lengerli, and Ozge Akbulut
- Abstract
TACC3, a transforming acidic coiled-coil (TACC) family member, is frequently upregulated in a broad spectrum of cancers, including breast cancer. It plays critical roles in protecting microtubule stability and centrosome integrity that is often dysregulated in cancers; therefore, making TACC3 a highly attractive therapeutic target. Here, we identified a new TACC3-targeting chemotype, BO-264, through the screening of in-house compound collection. Direct interaction between BO-264 and TACC3 was validated by using several biochemical methods, including drug affinity responsive target stability, cellular thermal shift assay, and isothermal titration calorimetry. BO-264 demonstrated superior antiproliferative activity to the two currently reported TACC3 inhibitors, especially in aggressive breast cancer subtypes, basal and HER2+, via spindle assembly checkpoint–dependent mitotic arrest, DNA damage, and apoptosis, while the cytotoxicity against normal breast cells was negligible. Furthermore, BO-264 significantly decreased centrosomal TACC3 during both mitosis and interphase. BO-264 displayed potent antiproliferative activity (∼90% have less than 1 μmol/L GI50 value) in the NCI-60 cell line panel compromising of nine different cancer types. Noteworthy, BO-264 significantly inhibited the growth of cells harboring FGFR3–TACC3 fusion, an oncogenic driver in diverse malignancies. Importantly, its oral administration significantly impaired tumor growth in immunocompromised and immunocompetent breast and colon cancer mouse models, and increased survival without any major toxicity. Finally, TACC3 expression has been identified as strong independent prognostic factor in breast cancer and strongly prognostic in several different cancers. Overall, we identified a novel and highly potent TACC3 inhibitor as a novel potential anticancer agent, inducing spindle abnormalities and mitotic cell death.
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- 2023
7. Figure S2 from A Highly Potent TACC3 Inhibitor as a Novel Anticancer Drug Candidate
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Ozgur Sahin, Erden Banoglu, Burcu Caliskan, Aytekin Akyol, Aynur Isik, Urartu O.S. Seker, Elif Duman, Ozge Saatci, Deniz Lengerli, and Ozge Akbulut
- Abstract
TACC3 is an independent prognostic factor for breast cancer.
- Published
- 2023
8. Supplementary Data from A Highly Potent TACC3 Inhibitor as a Novel Anticancer Drug Candidate
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Ozgur Sahin, Erden Banoglu, Burcu Caliskan, Aytekin Akyol, Aynur Isik, Urartu O.S. Seker, Elif Duman, Ozge Saatci, Deniz Lengerli, and Ozge Akbulut
- Abstract
Supplementary Methods
- Published
- 2023
9. Supplementary Tables from A Highly Potent TACC3 Inhibitor as a Novel Anticancer Drug Candidate
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Ozgur Sahin, Erden Banoglu, Burcu Caliskan, Aytekin Akyol, Aynur Isik, Urartu O.S. Seker, Elif Duman, Ozge Saatci, Deniz Lengerli, and Ozge Akbulut
- Abstract
Antibody list and primer sequences
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- 2023
10. Polymer Bridging Induced by a Single Additive Imparts Easy-To-Implement Green Machinability to Yttria-Stabilized Zirconia
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Ozge Akbulut, Can Akaoglu, Aleyna Beste Ozhan, Omid Akhlaghi, Lyn Zemberekci, Wael Ali Aldulaimi, Gizem Demir, and Mehmet Ali Gülgün
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Pressing ,Rapid prototyping ,Materials science ,Polymers and Plastics ,Process Chemistry and Technology ,Machinability ,Organic Chemistry ,Green body ,Protein coagulation ,visual_art ,visual_art.visual_art_medium ,Ceramic ,Composite material ,Polymer bridging ,Yttria-stabilized zirconia - Abstract
Cold isostatic pressing, gelcasting, and protein coagulation are the main methods to produce machinable green bodies of ceramics. They generally employ multiple additives, such as binders, dispersa...
- Published
- 2021
11. Hierarchical Organization of Structurally Colored Cholesteric Phases of Cellulose via 3D Printing
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Tadeusz Balcerowski, Burak Ozbek, Ozge Akbulut, and Ahu Gümrah DUMANLI
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biomimicry ,3D-printing ,Light ,Phases ,Color ,Cholesteric phasis ,Hydroxypropyl cellulose ,Shear-induced ,Cost Effectiveness ,Filaments ,Biomaterials ,Biomimetics ,Nanotechnology ,General Materials Science ,hierarchical photonic structures ,Hierarchical photonic structure ,Cellulose ,Photonic structure ,3-D printing ,cholesteric liquid crystals ,shear-induced deformation ,3D printing ,General Chemistry ,3D printers ,Printing ,Cholesteric liquid-crystal ,Chemical modification ,Biotechnology - Abstract
Structural color—a widespread phenomenon observed throughout nature is caused by light interference from ordered phases of matter. While state-of-the-art nanofabrication techniques can produce structural organization in small areas, we still lack a cost-effective, and scalable techniques to generate tunable color at sub-micron length scales. In this work, we produced structurally colored hydroxypropyl cellulose filaments with a suppressed angular color response by 3-d printing. Our systematic study of the morphology of the filaments reveals the key stages in the induction of a two-degree hierarchical order through 3-d printing. The first degree of order originates from the changing of the cholesteric pitch at a few hundred nm scale via chemical modification and tuning of the solid content of the lyotropic phase. Upon 3-d printing, the secondary hierarchical order of periodic wrinkling was introduced through the Helfrich-Hurault deformation of the shear-aligned cholesteric phases. Our work reveals the mechanism of the wrinkling behavior evidenced by detailed morphological characterization using SEM. In single layered filaments, we identified four morphological zones with varying order of wrinkles. Through this work, we demonstrate the possibility of modifying the wrinkling behavior and thus the angle dependence of the color response by changing the printing conditions.
- Published
- 2022
12. Abstract 5728: Inhibition of TACC3 blocks the growth of highly aggressive breast cancers with centrosome amplification
- Author
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Ozge Saatci, Ozge Akbulut, Metin Cetin, Vitali Sikirzhytski, and Ozgur Sahin
- Subjects
Cancer Research ,Oncology - Abstract
Centrosome amplification (CA) is a hallmark of cancer that is strongly associated with highly aggressive disease and worse clinical outcome. Clustering extra centrosomes into opposite spindle poles during mitosis is critical for preventing multipolar cell division and apoptosis in cancer cells with CA. However, the underlying molecular mechanisms have largely been unexplored. Here, we identified Transforming Acidic Coiled-Coil Containing Protein 3 (TACC3) as a novel CA-directed dependency, driving highly aggressive cell growth by forming distinct functional interactomes during cell cycle progression. We demonstrated, for the first time, that TACC3 interacts with the Kinesin Family Member C1 (KIFC1) via its TACC domain in mitotic cells with CA to promote centrosome clustering (CC) and facilitate mitotic progression. On the other hand, TACC3 interacts with the members of the nucleosome remodeling and deacetylase (NuRD) complex (HDAC2 and MBD2) in the nucleus of interphase cells with CA, thereby suppressing the transcription of key tumor suppressors to facilitate G1/S progression and cell survival. Inhibiting TACC3 in mitotic cells blocks the formation of TACC3/KIFC1 complex, leading to formation of multipolar spindles and activation of spindle assembly checkpoint (SAC)/CDK1/p-Bcl2 axis that ultimately results in mitotic cell death; whereas TACC3 inhibition in interphase cells blocks TACC3/HDAC2/MBD2 complex, leading to enhanced transcription of cyclin-dependent kinase inhibitors (e.g., p21 and p16) and apoptosis regulators (e.g., APAF1), ultimately causing p53-independent G1 arrest and strong apoptosis. Notably, inducing CA by chemical (cytochalasin D) or genomic (PLK4 overexpression or p53 loss) modulations renders cancer cells highly sensitive to TACC3 inhibition, showing the dependency of cells with CA to TACC3. Targeting TACC3 by small molecule inhibitors or CrispR-CAS9-mediated knock-out significantly reduces colony formation ability, inhibits the growth of organoids of patient-derived xenografts (PDXs) with CA, and strongly inhibits tumor growth in breast cancer cell line xenografts and PDXs with CA via induction of mitotic arrest and inhibition of G1/S progression. Notably, we demonstrated that high CA tumors express much higher levels of TACC3, and high TACC3 expression leads to drastically worse clinical outcome in cancer patients with CA. Altogether, our results show, for the first time, that TACC3 is a multifunctional driver of the growth of the highly aggressive breast tumors with CA and that targeting TACC3 is a promising approach to tackle this aggressive disease. Citation Format: Ozge Saatci, Ozge Akbulut, Metin Cetin, Vitali Sikirzhytski, Ozgur Sahin. Inhibition of TACC3 blocks the growth of highly aggressive breast cancers with centrosome amplification. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5728.
- Published
- 2023
13. Abstract 578: Novel bi-thiazole LOX inhibitors to overcome chemotherapy resistance in triple negative breast cancer
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Metin Cetin, Ozge Saatci, Abdol-Hossein Rezaeian, Ozge Akbulut, Nageswara Rao Chintada, Harrison Taylor, Breanna Pederson, Ioulia Chatzistamou, Hamed Shateri Najafabadi, Susan Lessner, Peggi Angel, Campbell McInnes, and Ozgur Sahin
- Subjects
Cancer Research ,Oncology - Abstract
Triple negative breast cancer (TNBC) is the most aggressive breast cancer subtype accounting for around 15% of all breast cancer patients and is responsible for 30% of breast cancer-related deaths. Although chemotherapy is the mainstay therapy for TNBC, development of resistance significantly reduces patients’ survival. Therefore, there is an urgent need to identify novel and effective treatment strategies to overcome chemoresistance. Recently, we identified hypoxia-induced ECM re-modeler, lysyl oxidase (LOX), a member of LOX family, as a key mediator of chemoresistance in TNBC. In this study, combining a robust screening platform for drug-like molecules and cell-based/recombinant protein assays, we identified bi-thiazole derivatives as novel potent LOX inhibitors. Further structure activity relationship (SAR) analysis resulted in two lead compounds: 6403, a relatively LOX-specific inhibitor, and 6415, a more LOX/LOXL2 dual inhibitor. Both compounds reduced collagen crosslinking and led to chemosensitization in TNBC cell lines in 3D culture and in chemoresistant TNBC PDX organoids. Furthermore, re-analyses of scRNA-Seq data of TNBC patients treated with neo-adjuvant chemotherapy with known chemoresponse or resistance showed that LOX+ cells were enriched upon chemotherapy only in treatment-refractory patients. Importantly, we identified a significant correlation between LOX and the gene sets of Reactive Oxygen Species (ROS) and DNA repair in TNBC patients treated with chemotherapy. Supporting this, increased chemotherapy penetration upon LOX inhibition resulted in elevated ROS levels and DNA damage in cells, leading to inhibition of FAK/Akt survival signaling. The efficacy of 6403 was tested in a chemoresistant TNBC PDX model where combination of doxorubicin with LOX inhibitor overcame doxorubicin resistance with no significant change in body weights. State-of-the-art MALDI-MSI and MP-SHG experiments showed efficient reduction of collagen content and crosslinking, respectively in PDX tumors upon LOX inhibition. Overall, these results show that novel bi-thiazole LOX inhibitors block collagen crosslinking and potentiates chemotherapy-induced ROS-DNA damage axis to overcome chemoresistance in TNBC. Citation Format: Metin Cetin, Ozge Saatci, Abdol-Hossein Rezaeian, Ozge Akbulut, Nageswara Rao Chintada, Harrison Taylor, Breanna Pederson, Ioulia Chatzistamou, Hamed Shateri Najafabadi, Susan Lessner, Peggi Angel, Campbell McInnes, Ozgur Sahin. Novel bi-thiazole LOX inhibitors to overcome chemotherapy resistance in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 578.
- Published
- 2023
14. Targeting TACC3 represents a novel vulnerability in highly aggressive breast cancers with centrosome amplification
- Author
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Ozge Saatci, Ozge Akbulut, Metin Cetin, Vitali Sikirzhytski, and Ozgur Sahin
- Abstract
Centrosome amplification (CA) is a hallmark of cancer that is strongly associated with highly aggressive disease and worse clinical outcome. However, there are no effective strategies targeting cancer cells with CA while sparing normal cells. Here, we identified Transforming Acidic Coiled-Coil Containing Protein 3 (TACC3) to be overexpressed in tumors with CA, and its high expression is associated with dramatically worse clinical outcome. We demonstrated that TACC3 forms distinct functional interactions in mitotic and non-mitotic cancer cells with CA to facilitate centrosome clustering (CC) and transcriptional repression of tumor suppressors, respectively. We showed, for the first time, that TACC3 interacts with the Kinesin Family Member C1 (KIFC1) via its TACC domain in mitotic cells with CA and inhibition of TACC3 blocks this interaction, leading to apoptosis via multipolar spindle formation and activation of spindle assembly checkpoint (SAC)/CDK1/p-Bcl2 axis. In interphase, TACC3 interacts with the members of the nucleosome remodeling and deacetylase (NuRD) complex (HDAC2 and MBD2) in nucleus, and its inhibition causes p53-independent G1 arrest and apoptosis by blocking these interactions and activating the transcription of key tumor suppressors (e.g., p21, p16 and APAF1). Notably, inducing CA by chemical (cytochalasin D) or genomic (PLK4 overexpression or p53 loss) modulations renders cancer cells highly sensitive to TACC3 inhibition. Targeting TACC3 by small molecule inhibitors or guide RNAs strongly inhibits growth of organoids and breast cancer cell line- and patient-derived xenografts with CA. Altogether our results pave the way towards therapeutic targeting of TACC3 in highly aggressive cancers.
- Published
- 2022
15. Targeting lysyl oxidase (LOX) overcomes chemotherapy resistance in triple negative breast cancer
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Pelin Gülizar Ersan, Fatma Gundogdu, Aysegul Uner, Vitali Sikirzhytski, Unal Metin Tokat, Aysegul Kaymak, Phillip Buckhaults, Hayriye Tatlı Doğan, Gamze Aykut, Carolyn E. Banister, Kemal Kosemehmetoglu, Omer Dizdar, Suhail A. Ansari, Umar Raza, Mehmet Dogan, Ozge Saatci, Ozgur Sahin, Aynur Isik, Ozge Akbulut, Sercan Aksoy, Aytekin Akyol, Yasser Riazalhosseini, Pouria Jandaghi, Raza, Umar, Ersan, Pelin G., Akbulut, Özge, Tokat, Ünal Metin, Aykut, Gamze, Ansari, Suhail A., and Şahin, Özgür
- Subjects
0301 basic medicine ,Integrins ,General Physics and Astronomy ,Apoptosis ,Triple Negative Breast Neoplasms ,Protein-Lysine 6-Oxidase ,Mice ,0302 clinical medicine ,RNA-Seq ,Hypoxia ,lcsh:Science ,Triple-negative breast cancer ,Cancer ,Multidisciplinary ,integumentary system ,Chemistry ,Extracellular Matrix ,Gene Expression Regulation, Neoplastic ,Targeting lysyl oxidase (LOX) ,030220 oncology & carcinogenesis ,Female ,Collagen ,Signal transduction ,Proto-oncogene tyrosine-protein kinase Src ,Signal Transduction ,Cell biology ,Science ,RNA-sequencing ,Down-Regulation ,Mice, Nude ,Lysyl oxidase ,Antineoplastic Agents ,macromolecular substances ,General Biochemistry, Genetics and Molecular Biology ,Article ,Triple negative breast cancer (TNBC) ,03 medical and health sciences ,Downregulation and upregulation ,In vivo ,Cell Line, Tumor ,Biomarkers, Tumor ,Animals ,Humans ,General Chemistry ,Fibronectins ,MicroRNAs ,030104 developmental biology ,HIF1A ,Drug Resistance, Neoplasm ,Focal Adhesion Kinase 1 ,Cancer research ,lcsh:Q ,Neoplasm Transplantation - Abstract
Chemoresistance is a major obstacle in triple negative breast cancer (TNBC), the most aggressive breast cancer subtype. Here we identify hypoxia-induced ECM re-modeler, lysyl oxidase (LOX) as a key inducer of chemoresistance by developing chemoresistant TNBC tumors in vivo and characterizing their transcriptomes by RNA-sequencing. Inhibiting LOX reduces collagen cross-linking and fibronectin assembly, increases drug penetration, and downregulates ITGA5/FN1 expression, resulting in inhibition of FAK/Src signaling, induction of apoptosis and re-sensitization to chemotherapy. Similarly, inhibiting FAK/Src results in chemosensitization. These effects are observed in 3D-cultured cell lines, tumor organoids, chemoresistant xenografts, syngeneic tumors and PDX models. Re-expressing the hypoxia-repressed miR-142-3p, which targets HIF1A, LOX and ITGA5, causes further suppression of the HIF-1α/LOX/ITGA5/FN1 axis. Notably, higher LOX, ITGA5, or FN1, or lower miR-142-3p levels are associated with shorter survival in chemotherapy-treated TNBC patients. These results provide strong pre-clinical rationale for developing and testing LOX inhibitors to overcome chemoresistance in TNBC patients., The development of chemoresistance is a major hurdle in triple negative breast cancer (TNBC). Here, the authors show that lysyl oxidase (LOX) is overexpressed in chemoresistant TNBCs, and when inhibited reduces collagen cross-linking, fibronectin fibril assembly, and downstream integrin signalling, overcoming resistance.
- Published
- 2020
16. Egf-Snx3-Egfr Axis Drives Tumor Progression And Metastasis In Triple-Negative Breast Cancers
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Ozgur Sahin, Rengul Cetin-Atalay, Sezen Guntekin Ergun, Esra Cicek, Didem Naz Dioken, Merve Oyken, Ayca Circir, Huib Ovaa, Ayse Elif Erson-Bensan, Ozge Akbulut Caliskan, Aysegul Sapmaz, Akbulut Çalışkan, Özge, and Akbulut Caliskan, Ozge
- Subjects
Cancer Research ,Endosome ,Triple Negative Breast Neoplasms ,Transfection ,Article ,Metastasis ,Breast cancer ,Downregulation and upregulation ,Epidermal growth factor ,Genetics ,medicine ,Gene silencing ,Humans ,Epidermal growth factor receptor ,Neoplasm Metastasis ,Molecular Biology ,biology ,medicine.disease ,Retromer complex ,ErbB Receptors ,Tumor progression ,Retromer ,Cancer research ,biology.protein ,Disease Progression ,Female ,Gene expression - Abstract
Epidermal growth factor receptor (EGFR) has critical roles in epithelial cell physiology. Over-expression and over-activation of EGFR have been implicated in diverse cancers, including triple-negative breast cancers (TNBCs), prompting anti-EGFR therapies. Therefore, developing potent therapies and addressing the inevitable drug resistance mechanisms necessitates deciphering of EGFR related networks. Here, we describe Sorting Nexin 3 (SNX3), a member of the recycling retromer complex, as a critical player in the epidermal growth factor (EGF) stimulated EGFR network in TNBCs. We show that SNX3 is an immediate and sustained target of EGF stimulation initially at the protein level and later at the transcriptional level, causing increased SNX3 abundance. Using a proximity labeling approach, we observed increased interaction of SNX3 and EGFR upon EGF stimulation. We also detected colocalization of SNX3 with early endosomes and endocytosed EGF. Moreover, we show that EGFR protein levels are sensitive to SNX3 loss. Transient RNAi models of SNX3 downregulation have a temporary reduction in EGFR levels. In contrast, long-term silencing forces cells to recover and overexpress EGFR mRNA and protein, resulting in increased proliferation, colony formation, migration, invasion in TNBC cells, and increased tumor growth and metastasis in syngeneic models. Consistent with these results, low SNX3 and high EGFR mRNA levels correlate with poor relapse-free survival in breast cancer patients. Overall, our results suggest that SNX3 is a critical player in the EGFR network in TNBCs with implications for other cancers dependent on EGFR activity.
- Published
- 2022
17. Microfluidics Integrated Microwave Sensors in Tandem with Optical Microscopy for Sizing and Material Classification of Single Cells and Microplastics
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Arda Secme, Uzay Tefek, Burak Sari, Hadi Sedaghat Pisheh, H. Dilara Uslu, Ozge Akbulut, Berk Kucukoglu, R. Tufan Erdogan, Hashim Alhmoud, Ozgur Sahin, M. Selim Hanay
- Published
- 2022
- Full Text
- View/download PDF
18. Hierarchical Organization of Structurally Colored Cholesteric Phases of Cellulose via 3D Printing (Small 8/2023)
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Tadeusz Balcerowski, Burak Ozbek, Ozge Akbulut, and Ahu Gümrah Dumanli
- Subjects
Biomaterials ,General Materials Science ,General Chemistry ,Biotechnology - Published
- 2023
19. Microfluidics-integrated microwave sensors for single cells size discrimination
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M. Selim Hanay, H. Dilara Uslu, Hadi Sedaghat Pisheh, Ozge Akbulut, R. Tufan Erdogan, Arda Secme, Akbulut, Özge, Erdoğan, R. Tufan, Seçme, Arda, Pisheh, Hadi Sedaghat, Uslu, H. Dilara, and Hanay, M. Selim
- Subjects
Heterodyne ,0303 health sciences ,Materials science ,business.industry ,Coplanar waveguide ,Resolution (electron density) ,Microfluidics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Cell size ,Microwave resonators ,law.invention ,03 medical and health sciences ,Resonator ,Optical microscope ,law ,Electrode ,Optoelectronics ,0210 nano-technology ,business ,MIMS ,Microwave ,030304 developmental biology - Abstract
Conference Name: IEEE MTT-S International Microwave Biomedical Conference, IMBioC 2020 Date of Conference: 14-17 December 2020 The size of a cell is one of the most fundamental biophysical parameters it possesses. Traditionally size measurements are done by using optical microscopy and quantitative phase imaging. However, a sensor with higher resolution, high throughput and lower cost is still needed. Here, a novel microfluidics-integrated microwave sensor is demonstrated to characterize single cells in real-time without labelling. Coplanar waveguide resonator is designed with a bowtie-shaped sensing electrodes separated by 50 μm. Cells are transported to sensing region by microfluidic channels and their sizes are measured simultaneously by the microwave sensors and optical microscopy. To enhance the microwave resolution, the microwave resonator is equipped with external heterodyne measurement circuitry detecting each and every cell passing through the sensing region. By comparing quantitative microscopic image analysis with frequency shifts, we show that microwave sensors can effectively measure cellular size. Our results indicate that microfluidics-integrated microwave sensors (MIMS) can be used for detecting.
- Published
- 2021
20. Universality of dissipative self-assembly from quantum dots to human cells
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F. Ömer Ilday, Ghaith Makey, E. Doruk Engin, Gökhan Yıldırım, Ozge Akbulut, Ozgur Sahin, Sezin Galioglu, H. Volkan Demir, Ü. Seleme Nizam, Kivanc Gungor, Roujin Ghaffari, Didem Dede, Serim Ilday, Onurcan Bektaş, Ozgun Yavuz, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, LUMINOUS! Centre of Excellence for Semiconductor Lighting & Displays, Makey, Ghaith, Galioğlu, Sezin, Ghaffari, Roujin, Yıldırım, Gökhan, Yavuz, Özgün, Akbulut, Özge, Şahin, Özgür, Güngör, Kıvanç, Dede, Didem, Demir, Hilmi Volkan, İlday, Fatih Ömer, and İlday, Serim
- Subjects
Physics ,Statistical Physics ,Continuous injection ,General Physics and Astronomy ,Self-assembly ,01 natural sciences ,010305 fluids & plasmas ,Universality (dynamical systems) ,Physics [Science] ,Quantum dot ,0103 physical sciences ,Dissipative system ,Statistical physics ,010306 general physics ,Brownian motion - Abstract
An important goal of self-assembly research is to develop a general methodology applicable to almost any material, from the smallest to the largest scales, whereby qualitatively identical results are obtained independently of initial conditions, size, shape and function of the constituents. Here, we introduce a dissipative self-assembly methodology demonstrated on a diverse spectrum of materials, from simple, passive, identical quantum dots (a few hundred atoms) that experience extreme Brownian motion, to complex, active, non-identical human cells (~1017 atoms) with sophisticated internal dynamics. Autocatalytic growth curves of the self-assembled aggregates are shown to scale identically, and interface fluctuations of growing aggregates obey the universal Tracy–Widom law. Example applications for nanoscience and biotechnology are further provided. Biological systems are able to self-assemble in non-equilibrium conditions thanks to a continuous injection of energy. Here the authors present a tool to achieve non-equilibrium self-assembly of synthetic and biological constituents with sizes spanning three orders of magnitude.
- Published
- 2020
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21. Incorporating steric hindrance into the additive design enables a robust formulation of alumina ink for extrusion-based 3D printing
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Navid Khani, Zahra Goharibajestani, Can Akaoglu, Ferdows Afghah, Omid Akhlaghi, Amin Hodaei, Ozge Akbulut, and Bahattin Koc
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Steric effects ,Fabrication ,Materials science ,Polymers and Plastics ,Inkwell ,business.industry ,Process Chemistry and Technology ,Organic Chemistry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,3D printing ,Nanotechnology ,visual_art ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,visual_art.visual_art_medium ,Extrusion ,Ceramic ,Current (fluid) ,business ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
The capabilities of additive manufacturing for fabrication of complex and thin-walled ceramic-based objects are restricted by the availability of ceramics inks. Formulations of current ink systems strictly depend on using a high content of organic additives (5-30 wt%). The high amounts of additives affect uniformity and dimensional accuracy of the final object. Here, we designed a single additive that enables printing of high aspect ratio and thin-walled structures (height/width = 58) from an ink of alumina nanoparticles that comprises very low organic content (i.e., 1.25 wt % of nanoparticles mass). In addition to the generally exploited electrostatic effect, this additive has purpose-driven tailoring to harness steric hindrance to control the viscoelastic response of ceramic suspensions and realize an optimum ink for extrusion-based 3D printing. We pursued a stepwise approach in developing such an additive through synthesis of series of copolymers with backbone monomers of 2-acrylamido-2-methylpropanesulfonic acid and acrylic acid and side chains of poly(ethylene glycol). When the optimized additive is used, the suspension attains ∼80 wt % solid loading−99% of the theoretical limit calculated by the Krieger−Dougherty equation. The shrinkage and deflection of the printed patterns as well as compactness and sinter-ability of dried structures are monitored. The printed structures did not experience any deformation or deflection during printing and reached 68% of theoretical density (TD: 3.98 g/cm3) after drying. This compactness allowed sintering at lower temperatures and improved dimensional control of the final product. Our approach to formulate ceramic inks enables the embodiment of fully aqueous systems with the utmost material content and has the potential to expand the limited portfolio of ceramic inks.
- Published
- 2019
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22. Abstract 3871: A novel TACC3 inhibitor as an anti-cancer agent in breast cancer
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Deniz Lengerli, Ozgur Sahin, Ozge Akbulut, Urartu Ozgur Safak Seker, Burcu Çalışkan, Elif Duman, Erden Banoglu, and Ozge Saatci
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Cancer Research ,business.industry ,DNA repair ,medicine.disease ,chemistry.chemical_compound ,Breast cancer ,Oncology ,chemistry ,In vivo ,Apoptosis ,Cancer research ,Medicine ,Kinome ,Growth inhibition ,business ,Ovarian cancer ,Mitosis - Abstract
Transforming Acidic Coiled-Coil Containing Protein 3 (TACC3) is a microtubule-associated protein that is localized on mitotic spindles and ensures proper chromosomal segregation and microtubule stability. TACC3 is frequently amplified or mutated, and was demonstrated to be a prognostic factor in a broad spectrum of cancers which makes it a highly attractive therapeutic target. TACC3 knockdown was demonstrated to cause mitotic spindle defects and prevent proper mitotic progression causing apoptotic cell death. Inhibition of TACC3 with the currently available small molecule inhibitors, KHS101 and SPL-B, has been shown to reduce the growth of glioblastoma xenografts, and suppress tumor growth in ovarian cancer xenografts, respectively. However, none of these TACC3 inhibitors is being tested in clinics potentially due to low systemic stability or high IC50 (inhibitory concentration 50) values. Here, by combining rational drug design and screening approaches, we aimed to identify a novel and more potent TACC3 inhibitor that is effective in in vitro and in vivo systems and that can be used as a mitotic blocker in breast cancer (BC). A library of test compounds was generated by replacing certain functional groups of already available TACC3 inhibitors with their isosteric equivalents to improve potency and drug-like properties. Then, the generated compounds were tested in vitro in terms of growth inhibition in a panel of breast cancer cell lines of different breast cancer subtypes. The compounds were also compared based on their effect on the cellular processes that TACC3 is involved in, and were further compared with genomic TACC3 inhibition by siRNAs. Finally, the most promising agent was tested in vivo in terms of its anti-tumorigenic effects. BO-264 was identified as the most potent TACC3 inhibitor that effectively kills breast cancer cells of different subtypes when administered at nanomolar dose. Moreover, it demonstrated superior inhibitory effects on mitotic progression, DNA repair, and cellular viability as compared to currently available inhibitors. Oral administration of BO-264 suppressed tumor growth in breast cancer xenografts at a dose that caused no apparent toxicity. Specificity of BO-264 to TACC3 protein was tested by kinome profiling and further validated by state-of-art binding assays. Currently, we are testing the pharmacokinetics and pharmacodynamics properties and organ toxicity of our inhibitor and performing the detailed molecular characterization of BO-264-mediated anti-tumor effects. Overall, our preclinical findings suggest that our novel compound (BO-264) is potentially a specific TACC3 inhibitor, causing growth inhibition in breast cancer cell lines and xenograft models by inducing mitotic arrest, DNA damage and apoptosis. Considering the critical importance of TACC3 as a cancer biomarker and driver of disease progression, BO-264 has great potential to be used as a novel therapeutic strategy in BC. Citation Format: Ozge Akbulut, Deniz Lengerli, Ozge Saatci, Elif Duman, Urartu Seker, Burcu Caliskan, Erden Banoglu, Ozgur Sahin. A novel TACC3 inhibitor as an anti-cancer agent in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3871.
- Published
- 2019
23. Abstract LT015: Overcoming chemotherapy resistance in triple negative breast cancer via targeting lysyl oxidase (LOX)
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Vitali Sikirzhytski, Carolyn E. Banister, Yasser Riazalhosseini, Phillip Buckhaults, Mikhail V. Chernov, Ozge Akbulut, Sercan Aksoy, Campbell McInnes, Aysegul Uner, Ozge Saatci, Ozgur Sahin, Aytekin Akyol, and Abdol-Hossein Rezaeain
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Cancer Research ,Gene knockdown ,Tumor microenvironment ,Kinase ,Chemistry ,Cancer ,Lysyl oxidase ,medicine.disease ,Oncology ,Cancer research ,medicine ,Doxorubicin ,Triple-negative breast cancer ,Proto-oncogene tyrosine-protein kinase Src ,medicine.drug - Abstract
Chemoresistance is a major obstacle in the treatment of triple negative breast cancer (TNBC), the most aggressive breast cancer subtype. To overcome chemoresistance, we have selected TNBC tumors for chemotherapy resistance in vivo, characterized their transcriptomes by RNA-sequencing and identified hypoxia-induced ECM re-modeler, lysyl oxidase (LOX) as a key inducer of chemoresistance. LOX overexpression has two distinct effects in hypoxic tumors treated with chemotherapy. As an ECM remodeler, LOX enhances collagen cross-linking and fibronectin assembly, thereby decreasing drug penetration. In addition, LOX exerts a surprising novel effect on transcription, increasing the expression of Integrin Subunit Alpha 5 (ITGA5), the major receptor for fibronectin (FN1), leading to activation of Focal Adhesion Kinase (FAK)/Src signaling and chemoresistance. Inhibition of LOX or ITGA5 with shRNA-mediated knockdown or inhibition of FAK or Src kinases with small molecule inhibitors in combination with doxorubicin greatly enhanced tumor growth inhibition in vivo relative to individual treatments. The role of LOX in chemoresistance has further been demonstrated using chemoresistant TNBC patient-derived xenografts (PDXs) and organoids, treated with doxorubicin alone or in combination with the LOX family inhibitor, BAPN. Notably, higher LOX, ITGA5, or FN1 levels are associated with shorter survival in chemotherapy treated TNBC patients. Currently available LOX inhibitors suffer from lack of specificity and high toxicity. To identify a more potent and selective LOX inhibitor, we performed a high-throughput screen (HTS) of a diversified small-molecule library. HTS resulted in identification of several hits that inhibit LOX enzymatic activity without any cytotoxicity. A lead compound was identified after the screening of hits based on their inhibitory effects on LOX enzymatic activity and the degree of chemosensitization in collagen-embedded cells. We are currently performing structure-activity relationship (SAR) analysis to optimize the lead compound for more potent activity and better drug-like properties. In addition, we are analyzing the mechanisms through which LOX enhances ITGA5 transcription and how the enzymatic activity of LOX contributes to transcriptional regulation. Our study provides a pre-clinical rationale for the development and testing of LOX inhibitors to overcome chemotherapy resistance in TNBC patients. Citation Format: Ozge Saatci, Ozge Akbulut, Abdol-Hossein Rezaeain, Carolyn Banister, Vitali Sikirzhytski, Sercan Aksoy, Aytekin Akyol, Aysegul Uner, Phillip Buckhaults, Mikhail Chernov, Campbell McInnes, Yasser Riazalhosseini, Ozgur Sahin. Overcoming chemotherapy resistance in triple negative breast cancer via targeting lysyl oxidase (LOX) [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr LT015.
- Published
- 2021
24. Rheological behavior of poly(acrylonitrile) concentrated solutions: effect of Sb2O3 nanoparticles on shear and extensional flow
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Yusuf Z. Menceloğlu, Omid Akhlaghi, and Ozge Akbulut
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Materials science ,Polymers and Plastics ,Polyacrylonitrile ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Viscoelasticity ,0104 chemical sciences ,chemistry.chemical_compound ,Payne effect ,Colloid and Surface Chemistry ,chemistry ,Rheology ,Shear (geology) ,Antimony trioxide ,Materials Chemistry ,Physical and Theoretical Chemistry ,Composite material ,0210 nano-technology ,Spinning - Abstract
This study investigates the effect of antimony trioxide (Sb2O3) nanoparticles on shear and extensional flow properties of concentrated polyacrylonitrile (PAN) solutions. Through shear rheology, a wide variety of rheological observations, such as Payne effect, applicability of Cox–Merz rule, and range of linear viscoelastic behavior (critical strain) were assessed. The presence of Sb2O3 nanoparticles was found to promote the non-linear viscoelasticity of the solutions and give rise to enhanced heterogeneous domains of PAN in the solution. In elongational flow, thinning dynamics of the nanocomposites was tracked to reproduce the dynamics of deformation in the spinline of the dry-jet wet spinning process. Increasing amounts of Sb2O3 nanoparticles in the solution were shown to improve the lifetime of the filament. All solutions were ruptured through elastocapillary behavior, while strengthened strain-hardening behavior was observed after the addition of Sb2O3 nanoparticles to the polymer solution.
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- 2016
25. A PCE-based rheology modifier allows machining of solid cast green bodies of alumina
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Burcin Ustbas, Ozge Akbulut, Gökay Avci, Omid Akhlaghi, Ceren Özbay, and Yusuf Z. Menceloğlu
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Materials science ,TA Engineering (General). Civil engineering (General) ,Ether ,02 engineering and technology ,TA401-492 Materials of engineering and construction. Mechanics of materials ,01 natural sciences ,chemistry.chemical_compound ,Machining ,Rheology ,0103 physical sciences ,Materials Chemistry ,Carboxylate ,Composite material ,010302 applied physics ,chemistry.chemical_classification ,Process Chemistry and Technology ,Superplasticizer ,Green body ,Polymer ,021001 nanoscience & nanotechnology ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Volume (thermodynamics) ,chemistry ,Ceramics and Composites ,0210 nano-technology - Abstract
The performance of a poly(carboxylate ether) (PCE)-based superplasticizer to enable the machining of green bodies that are solid cast from suspensions of alumina was investigated. An alumina loading of 35 vol% in the presence of 1.25 wt% superplasticizer was established to be suitable for lathing and removal of significant amount of material through drilling. A reduction of 77% in the diameter of green bodies that corresponds to a 59% reduction in volume was achieved. The lathed green bodies exhibited smooth terraces without visible cracks. All of the green bodies were sintered without a polymer burnout step.
- Published
- 2016
26. Silicone-based Composites as Surgical Breast Models for Oncoplasty Training
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Burcin Ustbas, Ece Polen Budak, Cem Yilmaz, Barkin Eldem, Deniz Kilic, Hande Eyisoylu, Ozge Akbulut, Vidan, A., and Shoag, D.
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medicine.medical_specialty ,Engineering ,breast model ,Breast surgery ,medicine.medical_treatment ,education ,Cold storage ,Mechanical engineering ,Mammoplasty ,030230 surgery ,TA401-492 Materials of engineering and construction. Mechanics of materials ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Breast cancer ,Silicone ,Surgical simulation ,medicine ,Medical physics ,Engineering(all) ,surgical model ,business.industry ,oncoplasty ,General Medicine ,medicine.disease ,chemistry ,030220 oncology & carcinogenesis ,Proper treatment ,Unavailability ,Breast reconstruction ,business - Abstract
Surgeons-in-training necessitate practice to improve their skill sets and the shift towards simulation-based trainings enables trainees to learn at their own pace and experience custom-based cases rather than responding to the immediate needs of the patients. Oncoplasty for breast cancer encompasses tumor removal and subsequent breast reconstruction; and there are several oncoplastic techniques to master for proper treatment of the patients. For training purposes, closest media to reality, fresh cadavers, are hard to obtain due to their price and/or unavailability. There is a need for a sustainable, reliable, and affordable platform to diffuse simulation-based trainings to medical curricula and provide trainings even in resource-limited settings. Silicone-based composite models can be designed and manufactured to fulfil the necessities of breast surgery such as precise incision, epidermal undermining, suturing, and resisting suture tension after excision of a considerable mass. We have shown the performance of such a stand-alone breast model for two oncoplastic techniques, “Batwing Mammoplasty” and “Modified Inferior Flap Rezai”. This model can be used in settings where it is difficult and/or expensive to find fresh cadavers. This cost-effective and practical solution also eliminates the need for chemical/cold storage and risk of infections/molding, thus making it a preferable tool for teaching hospitals and also for individual practice. In addition, the model is suitable to be used in self-diagnosis trainings, as well as a communication platform between surgeons and patients.
- Published
- 2016
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27. Shear and extensional rheological characterization of poly(acrylonitrile)/halloysite nanocomposite solutions
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Ozge Akbulut, Yusuf Z. Menceloğlu, and Omid Akhlaghi
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chemistry.chemical_classification ,Nanocomposite ,Materials science ,Polymers and Plastics ,Rheometry ,Organic Chemistry ,Polyacrylonitrile ,General Physics and Astronomy ,TA Engineering (General). Civil engineering (General) ,Polymer ,engineering.material ,Strain hardening exponent ,Halloysite ,chemistry.chemical_compound ,chemistry ,Shear (geology) ,Rheology ,Materials Chemistry ,engineering ,Composite material - Abstract
The shear and extensional flow properties of polyacrylonitrile (PAN) solution in the presence of halloysite nanotubes (HNTs) were investigated at an industrially relevant concentration of the polymer. In dynamic shear rheology, the elasticity and relaxation time of PAN solutions and the availability of heterogeneous PAN domains were found to increase with HNT content. Extensional flow behavior of PAN solutions were characterized using the capillary breakup extensional rheometry and increasing the amount of HNT content in the solution was found to increase the life-time of the filament and suppress strain hardening at high strains.
- Published
- 2015
28. Silicone-based simulation models for peripheral nerve microsurgery
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Burcin Ustbas Gul, Dilan Arslan, Mehmet Bayramiçli, Deniz Kilic Yanilmaz, and Ozge Akbulut
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Models, Anatomic ,medicine.medical_specialty ,Microsurgery ,medicine.medical_treatment ,education ,Silicones ,030230 surgery ,TA401-492 Materials of engineering and construction. Mechanics of materials ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Silicone ,Peripheral nerve ,Cadaver ,Epineurium ,Peripheral Nerve Injuries ,Medicine ,Humans ,Peripheral Nerves ,Universal testing machine ,business.industry ,Nerve injury ,Silicone oil ,Surgery ,medicine.anatomical_structure ,chemistry ,Microscopy, Electron, Scanning ,medicine.symptom ,business ,030217 neurology & neurosurgery ,Biomedical engineering - Abstract
Background: There is a need for a peripheral nerve model on which surgeons-intraining can simulate the repair of nerve injuries at their own pace. Although practicing on animal models/cadavers is considered the "gold standard" of microsurgical training, the proposed model aims to provide a platform for improving the technical skills of surgical trainees prior to their practice on cadaver/animal models. In addition, this model has the potential to serve as a standardized test medium for assessing the skill sets of surgeons. Methods: Several formulations of silicone were utilized for the design and fabrication of a model which realizes the hierarchical structure of peripheral nerves. The mechanical properties were characterized via the Universal Testing Machine; the damage caused by the needle on the entry sites was assessed through scanning electron microscopy (SEM). Results: Mechanical properties of the formulations of silicone were tested to mimic human peripheral nerves. A formulation with 83.3 wt% silicone oil and 0.1 wt% cotton fiber was chosen to be used as nerve fascicles. Both 83.3 wt% silicone oil with cotton fiber and 66.6 wt% silicone oil without fiber provided a microsuturing response similar to that of epineurium at a wall thickness of 1 mm. SEM also confirmed that the entry of the needle did not introduce significant holes at the microsuturing sites. Conclusions: The proposed peripheral nerve model mimicked human tissues mechanically and cosmetically, and a simulation of the repair of a fifth-degree nerve injury was achieved. (C) 2018 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
- Published
- 2018
29. Single additive enables 3D printing of highly loaded iron oxide suspensions
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Bahattin Koc, Ozge Akbulut, Dilek Sezer, Navid Khani, Buse Tatli, Omid Akhlaghi, Tunahan Aytas, Amin Hodaei, and Yusuf Z. Menceloğlu
- Subjects
Materials science ,Iron oxide ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,TA401-492 Materials of engineering and construction. Mechanics of materials ,0104 chemical sciences ,Dielectric spectroscopy ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Copolymer ,Magnetic nanoparticles ,Methacrylamide ,General Materials Science ,0210 nano-technology ,Suspension (vehicle) ,Ethylene glycol ,Iron oxide nanoparticles - Abstract
A single additive, a grafted copolymer, is designed to ensure the stability of suspensions of highly loaded iron oxide nanoparticles (IOPs) and to facilitate three-dimensional (3D) printing of these suspensions in the filament form. This poly (ethylene glycol)-grafted copolymer of N-[3(dimethylamino)propyl]methacrylamide and acrylic acid harnesses both electrostatic and steric repulsion to realize an optimum formulation for 3D printing. When used at 1.15 wt % (by the weight of IOPs), the suspension attains ∼81 wt % solid loading-96% of the theoretical limit as calculated by the Krieger-Dougherty equation. Rectangular, thick-walled toroidal, and thin-walled toroidal magnetic cores and a porous lattice structure are fabricated to demonstrate the utilization of this suspension as an ink for 3D printing. The electrical and magnetic properties of the magnetic cores are characterized through impedance spectroscopy (IS) and vibrating sample magnetometry (VSM), respectively. The IS indicates the possibility of utilizing wire-wound 3D printed cores as the inductive coils. The VSM verifies that the magnetic properties of IOPs before and after the ink formulation are kept almost unchanged because of the low dosage of the additive. This particle-targeted approach for the formulation of 3D printing inks allows embodiment of a fully aqueous system with utmost target material content.
- Published
- 2018
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30. A Comparison between Kinematic Models for Robotic Needle Insertion with Application into Transperineal Prostate Biopsy
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Chiara Zandonà, Andrea Roberti, Davide Costanzi, Burçin Gül, Özge Akbulut, Paolo Fiorini, and Andrea Calanca
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robotic needle insertion ,kinematic models ,models identification ,needle tip prediction ,robotic transperineal prostate biopsy ,Technology - Abstract
Transperineal prostate biopsy is the most reliable technique for detecting prostate cancer, and robot-assisted needle insertion has the potential to improve the accuracy of this procedure. Modeling the interaction between a bevel-tip needle and the tissue, considering tissue heterogeneity, needle bending, and tissue/organ deformation and movement is a required step to enable robotic needle insertion. Even if several models exist, they have never been compared on experimental grounds. Based on this motivation, this paper proposes an experimental comparison for kinematic models of needle insertion, considering different needle insertion speeds and different degrees of tissue stiffness. The experimental comparison considers automated insertions of needles into transparent silicone phantoms under stereo-image guidance. The comparison evaluates the accuracy of existing models in predicting needle deformation.
- Published
- 2024
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31. Modified poly(carboxylate ether)-based superplasticizer for enhanced flowability of calcined clay-limestone-gypsum blended Portland cement
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Tunahan Aytas, Aurélie Favier, Omid Akhlaghi, Buse Tatli, Yusuf Z. Menceloğlu, Ozge Akbulut, Karen Scrivener, Dilek Sezer, and Amin Hodaei
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Materials science ,Polymers ,0211 other engineering and technologies ,02 engineering and technology ,TA401-492 Materials of engineering and construction. Mechanics of materials ,Pozzolan ,law.invention ,chemistry.chemical_compound ,law ,021105 building & construction ,General Materials Science ,Carboxylate ,Composite material ,Metakaolin ,Acrylic acid ,Cement ,technology, industry, and agriculture ,Superplasticizer ,Building and Construction ,021001 nanoscience & nanotechnology ,Portland cement ,chemistry ,Chemical engineering ,Cementitious ,0210 nano-technology ,Workability - Abstract
Supplementary materials that are utilized to replace ordinary Portland cement (OPC) decrease the workability of the cementitious mixtures and superplasticizers are usually added to cement to control their fluidity. In general, current superplasticizers are solely optimized for single component systems such as OPC. Here, we report the performance of a series of a modified poly(carboxylate ether)-based superplasticizers (PCEs) in a ternary OPC-calcined clay-limestone blend. We have utilized: i) a co-monomer with high ionic character, 2-acrylamido-2-methylpropane sulfonic acid (AMPS) to be incorporated into the acrylic acid backbone of PCEs and ii) low density of polyethylene glycol (PEG) grafted chains < 0.01 mol/mol. The optimized polymer does not intercalate into the layered structure of calcined clay and preserves its steric size in the presence of high concentration of sulfate ions.
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- 2017
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32. Silicone-based composite materials simulate breast tissue to be used as ultrasonography training phantoms
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Mustafa Erkin Aribal, Deniz Kilic, Burcin Ustbas, Ozge Akbulut, and Ayhan Bozkurt
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Image-Guided Biopsy ,Materials science ,Acoustics and Ultrasonics ,Composite number ,Silicones ,TA Engineering (General). Civil engineering (General) ,Elastomer ,TA401-492 Materials of engineering and construction. Mechanics of materials ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Silicone ,Humans ,Dimethylpolysiloxanes ,Composite material ,Ultrasonography, Interventional ,Breast tissue ,business.industry ,Phantoms, Imaging ,Biopsy, Needle ,technology, industry, and agriculture ,Acoustics ,Equipment Design ,equipment and supplies ,Silicone oil ,Breast phantom ,Equipment Failure Analysis ,Nylons ,chemistry ,030220 oncology & carcinogenesis ,Attenuation coefficient ,Ultrasonography, Mammary ,Ultrasonography ,business - Abstract
A silicone-based composite breast phantom is fabricated to be used as an education model in ultrasonography training. A matrix of silicone formulations is tracked to mimic the ultrasonography and tactile response of human breast tissue. The performance of two different additives: (i) silicone oil and (ii) vinyl-terminated poly (dimethylsiloxane) (PDMS) are monitored by a home-made acoustic setup. Through the use of 75 wt% vinyl-terminated PDMS in two-component silicone elastomer mixture, a sound velocity of 1.29 +/- 0.09 x 10(3) m/s and an attenuation coefficient of 12.99 +/- 0.08 dB/cm-values those match closely to the human breast tissue-are measured with 5 MHz probe. This model can also be used for needle biopsy as well as for self-exam trainings. Herein, we highlight the fabrication of a realistic, durable, accessible, and cost-effective training platform that contains skin layer, inner breast tissue, and tumor masses. (C) 2018 Elsevier B.V. All rights reserved.
- Published
- 2017
33. Poly(carboxylate ether)-based superplasticizer achieves workability retention in calcium aluminate cement
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Ozge Akbulut, Omid Akhlaghi, and Yusuf Z. Menceloğlu
- Subjects
Engineering ,Multidisciplinary ,business.industry ,0211 other engineering and technologies ,Rolling shutter ,Mechanical engineering ,02 engineering and technology ,021001 nanoscience & nanotechnology ,TA401-492 Materials of engineering and construction. Mechanics of materials ,Article ,021105 building & construction ,Container (abstract data type) ,0210 nano-technology ,business - Abstract
Calcium aluminate cement (CAC) suffers from loss of workability in less than an hour (~15 minutes) after first touch of water. Current superplasticizers that are utilized to modify the viscosity of cement admixtures are designed to target ordinary Portland cement (OPC). The high affinity between these superplasticizers and cement particles were found to be detrimental in CAC systems. Utilization of a monomer that, instead, facilitates gradual adsorption of a superplasticizer provides workability retention. For the first time in literature, we report a superplasticizer that caters to the properties of CAC such as high rate of surface development and surface charge. While neat CAC was almost unworkable after 1 hour, with the addition of only 0.4% of the optimized superplasticizer, 90% fluidity retention was achieved.
- Published
- 2017
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34. Towards hard and soft packaging for die-scale ICs
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Lijun Teng, Zirhli, Onur, Burcin Ustbas, Sezer, Dilek, Hodaei, Amin, Ozge Akbulut, and Stokes, Adam A.
- Published
- 2016
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35. Separation of Nanoparticles in Aqueous Multiphase Systems through Centrifugation
- Author
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Charles R. Mace, Ozge Akbulut, Ashok A. Kumar, George M. Whitesides, Zhihong Nie, Matthew R. Patton, and Ramses V. Martinez
- Subjects
chemistry.chemical_classification ,Centrifuge ,Materials science ,Chromatography ,Aqueous solution ,Mechanical Engineering ,Nanoparticle ,Bioengineering ,02 engineering and technology ,General Chemistry ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,chemistry ,General Materials Science ,Centrifugation ,Nanorod ,Sample collection ,0210 nano-technology - Abstract
This paper demonstrates the use of aqueous multiphase systems (MuPSs) as media for rate-zonal centrifugation to separate nanoparticles of different shapes and sizes. The properties of MuPSs do not change with time or during centrifugation; this stability facilitates sample collection after separation. A three-phase system demonstrates the separation of the reaction products (nanorods, nanospheres, and large particles) of a synthesis of gold nanorods, and enriches the nanorods from 48 to 99% in less than ten minutes using a benchtop centrifuge.
- Published
- 2012
36. Application of Supramolecular Nanostamping to the Replication of DNA Nanoarrays
- Author
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Hee Tae Jung, and Anne M. Mayes, Jin-Mi Jung, Ryan D. Bennett, Robert E. Cohen, Ying Hu, Francesco Stellacci, and Ozge Akbulut
- Subjects
Molecular Conformation ,Supramolecular chemistry ,Metal Nanoparticles ,Bioengineering ,Nanotechnology ,Microscopy, Atomic Force ,PROBES ,Scanning probe microscopy ,Microscopy, Scanning Tunneling ,Dip-pen nanolithography ,General Materials Science ,Oligonucleotide Array Sequence Analysis ,chemistry.chemical_classification ,DIP-PEN NANOLITHOGRAPHY ,Chemistry ,SURFACES ,Mechanical Engineering ,Biomolecule ,DNA replication ,Nucleic Acid Hybridization ,DNA ,General Chemistry ,Stamping ,Condensed Matter Physics ,Nanostructures ,NANOFABRICATION ,Nanolithography ,ARRAY ,Nanoparticles ,Nucleic Acid Conformation ,Nanometre ,Gold ,CLUSTERS - Abstract
The rapid development of molecular biology is creating a pressing need for arrays of biomolecules that are able to detect smaller and smaller volumes of analytes. This goal can be achieved by shrinking the average size and spacing of the arrays' constituent features. While bioarrays with dot size and spacing on the nanometer scale have been successfully fabricated via scanning probe microscopy-based techniques, such fabrication methods are serial in nature and consequently slow and expensive. Additionally, the development of truly small arrays able to analyze scarce volumes of liquids is hindered by the present use of optical detection, which sets the minimum dot spacing on the order of roughly half the excitation wavelength. Here, we show that supramolecular nanostamping, a recently introduced truly parallel method for the stamping of DNA features, can efficiently reproduce DNA arrays with features as small as 14 +/- 2 nm spaced 77 +/- 10 nm. Moreover, we demonstrate that hybridization of these nanoarrays can be detected using atomic force microscopy in a simple and scaleable way that additionally does not require labeling of the DNA strands.
- Published
- 2007
37. Conductivity hysteresis in polymer electrolytes incorporating poly(tetrahydrofuran)
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Ozge Akbulut, Anne M. Mayes, Ikuo Taniguchi, Yang Shao-Horn, and Sundeep Kumar
- Subjects
chemistry.chemical_classification ,Materials science ,General Chemical Engineering ,Inorganic chemistry ,Polymer ,Conductivity ,Gel permeation chromatography ,chemistry.chemical_compound ,Differential scanning calorimetry ,chemistry ,Chemical engineering ,Electrochemistry ,Ionic conductivity ,Polymer blend ,Thermal analysis ,Tetrahydrofuran - Abstract
Conductivity hysteresis and room temperature ionic conductivities >10−3 S/cm were recently reported for electrolytes prepared from blends of an amphiphilic comb copolymer, poly[2,5,8,11,14-pentaoxapentadecamethylene (5-hexadecyloxy-1,3-phenylene)] (polymer I), and a linear multiblock copolymer, poly(oligotetrahydrofuran-co-dodecamethylene) (polymer II), following thermal treatment [F. Chia, Y. Zheng, J. Liu, N. Reeves, G. Ungar, P.V. Wright, Electrochim. Acta 43 (2003) 1939]. To investigate the origin of these effects, polymers I and II were synthesized in this work, and the conductivity and thermal properties of the individual polymers were investigated. AC impedance measurements were conducted on I and II doped with LiBF4 or LiClO4 during gradual heating to 110 °C and slow cooling to room temperature. Significant conductivity hysteresis was seen for polymer II, and was similarly observed for poly(tetrahydrofuran) (PTHF) homopolymer at equivalent doping levels. From thermogravimetic analysis (TGA), gel permeation chromatography (GPC) and 1H NMR spectroscopy, both polymer II and PTHF were found to partially decompose to THF during heat treatment, resulting in a self-plasticizing effect on conductivity.
- Published
- 2007
38. Synthesis and characterization of mixed ligand chiral nanoclusters
- Author
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Osman M. Bakr, Ozge Akbulut, Tabot M. D. Besong, Burcin Ustbas, Hikmet Coşkun, Zekiye Pelin Guven, Francesco Stellacci, Chakra Prasad Joshi, and Kellen M. Harkness
- Subjects
inorganic chemicals ,Stereochemistry ,Chemistry ,Ligand ,organic chemicals ,Chiral ligand ,Nanoparticle ,TA Engineering (General). Civil engineering (General) ,02 engineering and technology ,Mixed ligand ,010402 general chemistry ,021001 nanoscience & nanotechnology ,TA401-492 Materials of engineering and construction. Mechanics of materials ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,Nanoclusters ,Characterization (materials science) ,Inorganic Chemistry ,Yield (chemistry) ,health occupations ,polycyclic compounds ,heterocyclic compounds ,0210 nano-technology - Abstract
Chiral mixed ligand silver nanoclusters were synthesized in the presence of a chiral and an achiral ligand. The ratio of the ligands was changed to track the formation of these clusters. While the chiral ligand lead to nanoparticles, Presence of the achiral ligand induced the formation of nanoclusters with chiral properties.
- Published
- 2015
39. Extensional rheology and stability behavior of alumina suspensions in the presence of AMPS-modified polycarboxylate ether-based copolymers
- Author
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Ozge Akbulut, Omid Akhlaghi, and Yusuf Z. Menceloğlu
- Subjects
chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,technology, industry, and agriculture ,TA Engineering (General). Civil engineering (General) ,Strain hardening exponent ,Polyethylene ,Sulfonic acid ,equipment and supplies ,Dispersant ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,chemistry ,Rheology ,Materials Chemistry ,Copolymer ,Extensional viscosity ,Physical and Theoretical Chemistry ,Composite material ,Acrylic acid - Abstract
A series of polycarboxylate ether-based copolymers that include acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid, and polyethylene glycol-1000 was synthesized, and the performance of these copolymers as rheology modifiers in aqueous alumina suspensions was characterized. We discussed the effect of monomer feed ratio and molecular weight on dispersing ability of these copolymers and on extensional behavior of alumina suspensions. Results of zeta potential analysis determined that using the copolymers even at 0.5 wt.% results in all-negative zeta potentials for the entire pH range (2–12). These copolymers immensely affect the extensional rheological behavior of alumina suspensions—while 20 vol.% pure alumina suspension showed severe strain hardening behavior, suspensions with 1 wt.% copolymers and 35 vol.% alumina particles displayed no strain hardening. In this series, the copolymer with lowest molecular weight decreased the extensional viscosity of suspensions at the rupture of thread with three orders of magnitude as well.
- Published
- 2015
- Full Text
- View/download PDF
40. The Breathing Wall (BRALL)—Triggering Life (in)animate Surfaces
- Author
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Ozge Akbulut, Onur Zirhli, Ece Polen Budak, and Adam A. Stokes
- Subjects
0209 industrial biotechnology ,Visual Arts and Performing Arts ,media_common.quotation_subject ,05 social sciences ,Soft robotics ,050109 social psychology ,02 engineering and technology ,Art ,GeneralLiterature_MISCELLANEOUS ,Motion (physics) ,Computer Science Applications ,020901 industrial engineering & automation ,Human–computer interaction ,Human interaction ,Breathing ,0501 psychology and cognitive sciences ,Organic life ,Engineering (miscellaneous) ,Music ,Simulation ,ComputingMethodologies_COMPUTERGRAPHICS ,media_common - Abstract
This paper investigates the tactile possibilities of human interaction with synthetic biomorphic surfaces through an interdisciplinary collaboration between arts, materials science, mechanical, and electronics engineering. The authors created a breathing wall (BRALL) composed of nine silicone-based tiles that feel like flesh, breathe, emit sound, and respond to touch by pneumatic activation that is enabled by soft robotics technology. The authors believe combining a flesh-like material with soft motion and tactile responsiveness brings us a step closer to replicating/imitating organic life. The authors also question the potential of interacting with synthetic structures and what the social and cognitive implications of such exchanges could be.
- Published
- 2016
41. ÇOK FAZLI SİSTEMLERDE HÜCRE AYRIŞTIRILMASI
- Author
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Ozge Akbulut
- Subjects
Gynecology ,medicine.medical_specialty ,lcsh:T ,business.industry ,çok fazlı sistemler ,multiphase systems ,lcsh:Technology ,lcsh:TA1-2040 ,cell separation ,Cell separation ,Medicine ,lcsh:Engineering (General). Civil engineering (General) ,business ,hücre ayrıştırması - Abstract
Bu çalışma, çok fazlı polimer sistemlerinde, nanoparçacık ihtiva eden insan servikal kanser HeLa hücrelerinin, hücreler arasındaki yoğunluk farkına dayanılarak ayrıştırılması üzerinedir. Sulu çok fazlı sistemler, suda çözünen polimer ve/veya sürfaktanların çeşitli kombinasyonlarının karıştırılmasını takiben faz ayrışmasıyla oluşur. Sistemin fazları yoğunluklarına göre üst üste dizilirler ve birbirine komşu her iki fazın arasında yoğunluk-adımı olarak hareket edebilen bir interfaz bulunur. Bu interfaz, nesneleri yakalayabilecek bir bariyer görevi görür ve faz ayrışmasıyla oluştuğu için kararlıdır. Bu sistemler hazırlandıktan ve ayrıştırma için eniyilendikten sonra, hücrelerin sisteme eklenmesi ve sentrifügasyon yardımı ile ayrıştırma sağlanır. Bu çalışmada, altın nanoparçacıklarıyla kontrollü şekilde etkileşen HeLa hücrelerinin, yoğunluklarındaki değişime istinaden, sulu çok fazlı sistemlerde ayrıştırılmaları gösterilmiştir.
- Published
- 2017
42. Supramolecular replication of peptide and DNA patterned arrays
- Author
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Molly M. Stevens, Francesco Stellacci, Ozge Akbulut, and Anna Laromaine
- Subjects
Microarray ,Protein design ,Supramolecular chemistry ,HELICAL COILED-COILS ,Nanotechnology ,Peptide ,02 engineering and technology ,BUNDLES ,MOLECULES ,03 medical and health sciences ,chemistry.chemical_compound ,MICROARRAY ,SYSTEMS ,parasitic diseases ,Materials Chemistry ,SPECIFICITY ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,STABILITY ,PROTEIN-DESIGN ,technology, industry, and agriculture ,General Chemistry ,Replication (microscopy) ,ACIDS ,021001 nanoscience & nanotechnology ,chemistry ,Biophysics ,TECHNOLOGIES ,0210 nano-technology ,DNA - Abstract
Here we present a novel approach to the parallel fabrication of protein and protein/DNA features on surfaces.
- Published
- 2010
43. Aqueous Multiphase Systems of Polymers and Surfactants Provide Self-Assembling Step-Gradients in Density
- Author
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Nathan D. Shapiro, Ashok A. Kumar, Ozge Akbulut, Matthew R. Patton, George M. Whitesides, Ratmir Derda, and Charles R. Mace
- Subjects
Change over time ,chemistry.chemical_classification ,Aqueous solution ,Chemistry ,Polymers ,Surface Properties ,Pellets ,Water ,General Chemistry ,Polymer ,Biochemistry ,Catalysis ,Article ,Solvent ,Surface-Active Agents ,Colloid and Surface Chemistry ,Chemical engineering ,Self assembling ,Centrifugation, Density Gradient ,Organic chemistry ,Thermodynamics ,Surface-active agents - Abstract
This Communication demonstrates the generation of over 300 phase-separated systems-ranging from two to six phases-from mixtures of aqueous solutions of polymers and surfactants. These aqueous multiphase systems (MuPSs) form self-assembling, thermodynamically stable step-gradients in density using a common solvent, water. The steps in density between phases of a MuPS can be very small (Δρ ≈ 0.001 g/cm(3)), do not change over time, and can be tuned by the addition of co-solutes. We use two sets of similar objects, glass beads and pellets of different formulations of Nylon, to demonstrate the ability of MuPSs to separate mixtures of objects by differences in density. The stable interfaces between phases facilitate the convenient collection of species after separation. These results suggest that the stable, sharp step-gradients in density provided by MuPSs can enable new classes of fractionations and separations based on density.
- Published
- 2012
44. Integration of paper-based microfluidic devices with commercial electrochemical readers
- Author
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Frédérique Deiss, Ozge Akbulut, Xinyu Liu, George M. Whitesides, and Zhihong Nie
- Subjects
Blood Glucose ,Paper ,Medical diagnostic ,Materials science ,Ethanol ,Blood Glucose Self-Monitoring ,Microfluidics ,Biomedical Engineering ,Analytical chemistry ,Bioengineering ,Nanotechnology ,General Chemistry ,Paper based ,Electrochemical Techniques ,Microfluidic Analytical Techniques ,Biochemistry ,Article ,Human health ,Cholesterol ,Linear Models ,Humans ,Lactic Acid ,Food Analysis - Abstract
The combination of simple Electrochemical Micro-Paper-based Analytical Devices (EµPADs) with commercially available glucometers allows rapid, quantitative electrochemical analysis of a number of compounds relevant to human health (e.g., glucose, cholesterol, lactate, and alcohol) in blood or urine.
- Published
- 2010
45. ChemInform Abstract: Fabrication of Biomolecular Devices via Supramolecular Contact-Based Approaches
- Author
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Arum Amy Yu, Ozge Akbulut, and Francesco Stellacci
- Subjects
Focus (computing) ,Fabrication ,Point (typography) ,Chemistry ,Microcontact printing ,Fabrication methods ,Supramolecular chemistry ,Nanotechnology ,General Medicine ,Contact print - Abstract
This tutorial review provides an outlook on contact-based fabrication methods suitable for biomolecular platforms. Contact-based methods have emerged in response to serial and expensive fabrication techniques that built devices in a serial way, typically point by point or region by region. The review surveys the biological applications of microcontact printing and affinity contact printing. There is a special focus on DNA printing methods harnessing the supramolecular interactions between two complementary DNA strands.
- Published
- 2010
46. Fabrication of biomolecular devices via supramolecular contact-based approaches
- Author
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Ozge Akbulut, Arum Amy Yu, and Francesco Stellacci
- Subjects
Focus (computing) ,Fabrication ,Point (typography) ,Computer science ,Supramolecular chemistry ,Nanotechnology ,General Chemistry ,Fabrication methods ,Microcontact printing ,Animals ,Humans ,Microtechnology ,Printing ,Ink ,Contact print ,Oligonucleotide Array Sequence Analysis - Abstract
This tutorial review provides an outlook on contact-based fabrication methods suitable for biomolecular platforms. Contact-based methods have emerged in response to serial and expensive fabrication techniques that built devices in a serial way, typically point by point or region by region. The review surveys the biological applications of microcontact printing and affinity contact printing. There is a special focus on DNA printing methods harnessing the supramolecular interactions between two complementary DNA strands.
- Published
- 2009
47. Superwetting nanowire membranes for selective absorption
- Author
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Steven L. Suib, Francesco Stellacci, Jing Kong, Xiaogang Liu, Junqing Hu, Ozge Akbulut, and Jikang Yuan
- Subjects
Materials science ,Biomedical Engineering ,Nanowire ,Bioengineering ,Nanotechnology ,Adsorption ,Superhydrophilicity ,General Materials Science ,Thermal stability ,Electrical and Electronic Engineering ,chemistry.chemical_classification ,Nanotubes ,Biomolecule ,Membrane structure ,Membranes, Artificial ,Oxides ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Nanostructures ,Membrane ,chemistry ,Manganese Compounds ,Wettability ,Wetting ,Environmental Pollution ,Oils - Abstract
The construction of nanoporous membranes is of great technological importance for various applications, including catalyst supports, filters for biomolecule purification, environmental remediation and seawater desalination. A major challenge is the scalable fabrication of membranes with the desirable combination of good thermal stability, high selectivity and excellent recyclability. Here we present a self-assembly method for constructing thermally stable, free-standing nanowire membranes that exhibit controlled wetting behaviour ranging from superhydrophilic to superhydrophobic. These membranes can selectively absorb oils up to 20 times the material's weight in preference to water, through a combination of superhydrophobicity and capillary action. Moreover, the nanowires that form the membrane structure can be re-suspended in solutions and subsequently re-form the original paper-like morphology over many cycles. Our results suggest an innovative material that should find practical applications in the removal of organics, particularly in the field of oil spill cleanup.
- Published
- 2008
48. Fourier transform infrared and 1h nuclear magnetic resonance spectroscopic findings of silicone oil removed from eyes and the relationship of emulsification with retinotomy and glaucoma
- Author
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Burçin Yıldız, Hulya Gungel, Ozge Akbulut, and Yusuf Menceoğlu
- Subjects
Adult ,Male ,medicine.medical_specialty ,Time Factors ,genetic structures ,Adolescent ,Glaucoma ,Aphakia, Postcataract ,Aphakia ,Retinal detachment surgery ,Retina ,Gel permeation chromatography ,chemistry.chemical_compound ,Optics ,Ophthalmology ,Spectroscopy, Fourier Transform Infrared ,Medicine ,Humans ,Silicone Oils ,Nuclear Magnetic Resonance, Biomolecular ,Aged ,business.industry ,Viscosity ,Vitreoretinopathy, Proliferative ,Retinal Detachment ,General Medicine ,Middle Aged ,medicine.disease ,eye diseases ,Silicone oil ,chemistry ,Chromatography, Gel ,Drainage ,Emulsions ,Female ,sense organs ,business - Abstract
Purpose: To investigate whether structural changes occur in silicone oil that has been left in the eye for different periods and to research the relationship of emulsification with the time during which silicone oil is left in the eye, glaucoma, and wide relaxing retinotomy. Methods: Samples of silicone oil were randomly removed from the eyes of 22 patients. Gel permeation chromatography (GPC) and spectroscopy were used to identify any changes in the silicone oil. The relationship between spectroscopically determined emulsification with time spent in the eye, glaucoma, and wide relaxing retinotomy was investigated statistically. Results: GPC revealed that no change was found in the 1,000-centistoke silicone oil model after it had been removed from the eye. Spectroscopy identified absorption peaks belonging to water in addition to those belonging to the functional groups. The relationships between emulsification and time spent in the eye and glaucoma were found to be statistically insignificant, while that between emulsification and wide relaxing retinotomy was statistically significant. Conclusion: Intravitreally applied silicone oil undergoes no structural change. Wide relaxing retinotomy constitutes a risk factor for silicone oil emulsification, which can occur earlier than expected and before it can be observed clinically.
- Published
- 2005
49. Electrochemical Microfluidic Paper-based Analytical Devices using a Glucometer for Point-of-care Detection of Multiple Analytes
- Author
-
Frédérique T. Deiss, Zhihong Nie, Xinyu Liu, Ozge Akbulut, and George M. Whitesides
- Abstract
not Available.
- Published
- 2011
50. Integration of paper-based microfluidic devices with commercial electrochemical readersElectronic supplementary information (ESI) available: fabrication of EµPADs, measurement of analytes in EµPADs using glucometers, assays, electrochemical behavior of EµPADs, and performance of two-layer EµPADs. See DOI: 10.1039/c0lc00237b
- Author
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Zhihong Nie, Frédérique Deiss, Xinyu Liu, Ozge Akbulut, and George M. Whitesides
- Subjects
MICROFLUIDIC devices ,ELECTROCHEMISTRY ,MICROFABRICATION ,QUANTITATIVE research ,BLOOD cholesterol ,URINE - Abstract
The combination of simple Electrochemical Micro-Paper-based Analytical Devices (EµPADs) with commercially available glucometers allows rapid, quantitative electrochemical analysis of a number of compounds relevant to human health (e.g., glucose, cholesterol, lactate, and alcohol) in blood or urine. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
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