Özge Akbulut

Özge Akbulut

Dr. Akbulut is an Assistant Professor at Sabancı University since February 2012. She received her B.S. in Materials Science and Engineering at Sabancı University in 2004. Her PhD from Massachusetts Institute of Technology (MIT, 2009) focused on cost-effective fabrication of biomolecular devices and surface science. She continued her studies as a post-doctoral fellow in Whitesides Group at Harvard University (2009–2011) on developing tools/techniques for resource-limited settings. Dr. Akbulut’s current research interests are rheology modifiers and silicone-based composites. She also founded a company, Surgitate, on tactile surgical training platforms, in 2014.


Rheology Of Cement

Rheology Of Cement

We develop superplasticizers for ordinary Portland cement (OPC) and calcium aluminate cement (CAC). Poly(carboxylate ether)-based superplasticizers (PCEs) are used to modify the viscosity, slump flow, and slump retention of cement mixtures. From the first touch of water, CAC loses its flowability in less than 1 hour and commercially available superplasticizers are developed to cater the needs of OPC-based systems. The superplasticizer that we have developed for CAC is the first of its kind to address higher charge, surface development, and fast kinetics of this specialty cement (EP 3056476 A1, https://www.google.com/patents/EP3056476A1?cl=en).

The pictures demonstrate the performance of superplasticizers—CAC system, top: with an incompatible superplasticizer, below: with the superplasticizer that we designed (SU-PCE). An addition of 0.4 wt% SU-PCE was enough to preserve the flowability of CAC in longer periods.
Team & Collaborators & Partners

Team

* Omid Akhlaghi, PhD candidate
* Burcin Ustbas, PhD candidate
* Onur Ozensoy, MS candidate
* Amin Hodaei, MS candidate
* Dilek Sezer, MS candidate

Alumni

* Pelin Guven, MS, now at EPFL
* Gokay Avci, MS, now at Koc University

Partners

* Farplas
* ARYA
* Inovent
* SUCool

Collaborators

rheology of ceramic suspensions and cement
* Prof. Yusuf Menceloglu, Materials Science and Eng., Sabanci University, since 2012
* Prof. Bahattin Koc (additive manufacturing), Industrial Eng., Sabanci University, since 2016
* Prof. Karen Scrivener, Dr. Aurelie Favier, Materials Science and Eng., EPFL, since 2015
silicone-based composite models for surgical simulation
* Prof. Bahadir Gulluoglu, Marmara University Department of Medicine
* Dr. Cem Yilmaz, Istanbul Oncology Hospital
* Prof. Erkin Aribal (ultrasonography models), Marmara University Department of Medicine
nanoclusters
* Prof. Francesco Stellacci, Materials Science and Eng., EPFL
* Prof. Osman Bakr, Materials Science and Eng., KAUST
Machinable Ceramics

Machinable Ceramics

We designed a grafted copolymer that allows high loadings in alumina suspensions such that once solid cast and dried, green bodies can withstand forces of machining. We achieved a reduction of 77 % in the diameter that corresponds to a 59 % reduction in volume. Due to the low amount of the additive used, there is no need for a burn out step before sintering as well. To our knowledge, this work is the first one in literature that can fabricate ceramic objects with thin walls through machining from a totally aqueous, non-toxic system.

http://www.sciencedirect.com/science/article/pii/S0272884215020805
Publications & Patents

Publications & Patents

Publications

Gungel, H., Menceloglu, Y., Yildiz, B. and Akbulut, O. “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”, Retina, 25, 332–338 (2005).

Akbulut, O., Taniguchi, I., Kumar, S., Shao-Horn, Y. and Mayes, A.M. “Conductivity hysteresis in polymer electrolytes incorporating poly(tetrahydrofuran)”, Electrochimica Acta, 52, 1983–1989 (2007).

Akbulut, O., Jung, J.-M., Bennett, R.D., Hu, Y., Jung, H.-T. Cohen, R.E., Mayes, A.M. and Stellacci, F. “Application of supramolecular nanostamping to the replication of DNA nanoarrays”, Nano Letters, 7, 3493–3498 (2007).

Liu, X., Yuan, J., Akbulut, O., Hu, J., Suib, S.L., Kong, J. and Stellacci, F. “Superwetting nanowire membranes or selective absorption”, Nature Nanotechnology, 3, 332–336 (2008).

Laromaine, A.*, Akbulut, O.*, Stellacci, F. and Stevens, M. M. “Supramolecular replication of peptide and DNA patterned arrays”, Journal of Materials Chemistry, 20, 68–70 (2010).(*: equal contribution; cover article)

Akbulut, O., Yu, A. A. and Stellacci F. “Fabrication of biomolecular devices via contact-based methods”, Chemical Society Reviews, 39, 30–37(2010).

Nie, Z., Deiss, F., Liu, X., Akbulut, O. and Whitesides, G. M. “Integration of paper-based microfluidic device with commercial elecrochemical readers”, Lab on a Chip, 10, 3163–3169 (2010).

Mace, C. R., Akbulut, O., Kumar, A. A., Shapiro, N. D., Derda, R., Patton, M. R. and Whitesides, G. M. “Aqueous multiphase systems of polymers and surfactants provide self-assembling gradients in density”, Journal of American Chemical Society, 134, 9094–9097 (2012).

Akbulut, O., Mace, C. R., Martinez, R. V., Kumar, A. A., Nie, Z., Patton, M. R. and Whitesides, G. M. “Separation of nanoparticles in aqueous multiphase systems through centrifugation”, Nano Letters, 12, 4060–4064 (2012).

Akhlaghi, O., Akbulut, O., and Menceloglu, Y. Z. “Extensional rheology and stability behavior of alumina suspensions in the presence of AMPS-modified poly(carboxylate ether)-based copolymers”, Colloid and Polymer Science, 293, 2867–2876 (2015).

Akhlaghi, O., Akbulut, O., and Menceloglu, Y. Z. “Shear and extensional rheological characterization of poly(acrylonitrile)/halloysite nanocomposite solutions”, European Polymer Journal, 73, 17–25 (2015).

Budak, E. P., Zirhli, O., Stokes, A. A., and Akbulut, O. “The Breathing Wall  (BRALL)—Triggering life in(animate) surfaces”,  Leonardo Transactions, 49 (2016).

Avci, G., Akhlaghi, O., Ustbas, B., Ozbay, C., Menceloglu, Y. Z. and Akbulut,O. “A PCE-based rheology modifier allows machining of solid cast green bodies of alumina”, Ceramics International, 42, 3757–3761 (2016).

Akbulut, O. “We should do what we do best in our usual ways”, Journal of Medical and Surgical Research, 2, 184–185 (2016).

Guven, Z. P., Ustbas, B., Harkness, K. M., Coskun, H., Joshi, C. P., Besong, T. M. D, Stellacci, F., Bakr, O. M., and Akbulut, O. “Synthesis and characterization of mixed ligand chiral nanoclusters”, Dalton Transactions, 45,   12297–11300 (2016).

Akhlaghi, O., Menceloglu, Y. Z., and Akbulut, O. “Shear and extensional rheological study of poly(acrylonitrile)-Sb2O3 nanocomposite solutions”, Colloid and Polymer Science, 294,
1463–1473 (2016).

Kilic, D., Ustbas, B., Budak, E. P.,Eyisoylu, H., Yilmaz, C., Eldem, B., and Akbulut, O.  “Silicone-based composites as surgical breast models for oncoplasty training”, Procedia Engineering, 159, 104–107 (2016).

Akhlaghi, O., Menceloglu, Y. Z., and Akbulut, O. “Poly(carboxylate ether)-based superplasticizer achieves workability retention in calcium aluminate cement”, Nature Scientific Reports, doi: 10.1038/srep41743 (2017).

Patents
WO/2012/024688 (HU3865) - Multiphase systems and uses thereof - Inventors:  Charles R. Mace, Ozge Akbulut Halatci, Ashok A. Kumar, Nathan D. Shapiro, and George M. Whitesides. (Publication date: February, 23, 2012

WO/2012/024690 (HU4262) - Multiphase systems having multiple phase properties - Inventors:  Ozge Akbulut Halatci, Charles R. Mace, Ashok A. Kumar, Zhihong Nie, and George M. Whitesides. (Publication date: February, 23, 2012)

WO/2012/024691 (HU4263) - Multiphase systems for analysis of solid materials - Inventors:  Charles R. Mace, Ozge Akbulut Halatci, Ashok A. Kumar, Nathan D. Shapiro, and George M. Whitesides. (Publication date: February, 23, 2012)

US20120302456 A1 (HU3985) - A vertical flow-through device for multiplexed ELISA driven by wicking-Inventors: Max Narovlyansky, Ozge Akbulut Halatci, Charles R. Mace, and George M. Whitesides. (Publication date: November, 11, 2012)

EP15155210.6 - An additive for suspensions- Inventors: Omid Akhlaghi, Ozge Akbulut, and Yusuf Z. Menceloglu. (Publication date: August, 18, 2016)

PCT/TR2016/050354 –An admixture and ink comprising such mixture- Inventors: Omid Akhlaghi, Amin Hodaei, Dilek Sezer, and Ozge Akbulut (Application date: September, 26, 2016)

Surgical Models

Surgical Models

Lack of cadavers and fresh tissue/organ models hinders the quality of medical education; therefore, there is a need for a reliable and sustainable training medium for evergrowing number of medical students and personnel. We design and fabricate silicone-based surgical models that are engineered to simulate mechanical responses of real organs to incision, dissection, and suturing. Different suturing techniques, benign mass removal, and complicated oncoplastic surgery can be practiced on our skin, breast, and vascular models. We aim to improve the quality of surgical trainings via this practical, affordable, and tactile simulation platform.

* http://www.surgitate.com
* http://www.sciencedirect.com/science/article/pii/S1877705816322780
BRALL
Classes

Classes

* MAT 404, Polymer Physics
* MAT 402, Polymer Engineering II
* ENS 481, Materials Selection in Product Design (Spring 2017)
* ENS 205, Introduction to Materials Science

- Karakoy Science and Culture Academy
- Sabanci University Summer School for High School Students

VIKINGS are coming soon.
Talks & Seminars & Panels

Talks & Seminars & Panels

* École Polytechnique Fédérale de Lausanne (EPFL), 2011 & 2016
* Bilkent University, 2012
* Koç University, 2012 & 2015
* Institut de Ciència de Materials de Barcelona (ICMAB), 2012
* King Abdullah University of Science and Technology (KAUST), 2012 & 2015
* Turkish Women International Network (Turkish WIN), 2015
* The University of Edinburgh, 2015
* Falling Walls Berlin, 2015
* Anadolu Foundation, 2016
* Uludag University, 2016
* TEDx Reset, 2016
* Inonu University, 2016
* Stiftung Charite Global Entrepreneurship Summit on Healthcare, 2016
* World Intellectual Patent Organization/UNESCO, 2016
* Katholieke Universiteit Leuven, 2016
* Istanbul Design Biennial, 2016
* Aalto University, 2016
* University College London, 2017
More On Rheology

More On Rheology

We focused on capillary breakup extensional rheometer (CaBER) response of alumina suspensions since elongational flow of ceramic suspensions is present in many industrial processing methods. The introduction of an optimized PCE at 1 wt% into 68 wt% alumina suspension reduces the extensional viscosity and eliminates strain hardening behavior. Electrokinetic studies showed that using this PCE leads to all-negative zeta potentials for the entire pH range (2–12) even at 0.5 wt% addition.

http://link.springer.com/article/10.1007/s00396-015-3683-8

We studied the shear and extensional flow properties of polyacrylonitrile (PAN)/dimethylacetamide solutions in the presence of antimony trioxide nanoparticles (Sb2O3) at industrially relevant polymer and filler concentrations for this system. We tracked thinning dynamics of these solutions by capillary breakup extensional rheometery (CaBER) since manufacturing of polymer- Sb2O3 nanocomposites through spinning necessitates visco-elasto-capillary understanding. This article is the first of its kind to understand PAN/Sb2O3 nanocomposites with low particle loadings since rheological behavior of polymeric solutions is closely related to physical properties of polymeric systems and has direct effect on polymer processing and technology. We found that the introduction of Sb2O3 nanoparticles to PAN solution enhances the life-time of the filament, physical structures, and elasticity of polymer chains which are the results of entrapment of polymer chains and break of solvent bridges by filler nanoparticles.

http://link.springer.com/article/10.1007%2Fs00396-016-3907-6

We characterized the shear and extensional flow properties of polyacrylonitrile (PAN)/dimethylacetamide solutions in the presence of halloysite nanotubes (HNTs) at industrially relevant polymer and filler concentrations for this system. We monitored thinning dynamics of these solutions by capillary breakup extensional rheometery (CaBER). We found that the introduction of HNTs to PAN solution improves the life-time of the filament. Additionally, the filled solutions exhibited enhanced physical structures and elasticity. The shear and extensional behavior of PAN solution with ≤ 8 wt% HNTs showed that these solutions could be still processed under similar conditions as neat PAN solution.

http://www.sciencedirect.com/science/article/pii/S0014305715004887
Previous

Supramolecular Nanostamping (SuNS): A Method for Parallel Fabrication of Biomolecular Devices

DNA arrays have revolutionized the field of biomedicine since they allow the analyses of several different DNA sequences in parallel. [1] Current methods to fabricate such arrays are serial in nature resulting in high prices that prevent the extensive utilization of those arrays. [1,2] Supramolecular Nanostamping is devised to solve this problem by harnessing the reversible bond formation between complementary DNA strands. This contact based technique replicates DNA arrays in a three steps: 1) Hybridization, 2) Contact and 3) Dehybridization. [3]

References
[1] Heller, M.J., Annu. Rev. Biomed. Eng., 2002, 4, 129–153.
[2] Dufva, M., Biomol. Eng., 2005, 22, 173–184.
[3] Yu, A. A., Savas, T. A., Taylor, G. S., Guiseppe-Elie, A., Smith, H.I., and Stellacci, F. Nano Lett., 2005, 5, 1061–1064.

Replication of DNA Nanoarrays

The amount of analyte needed in an array scales with the feature size and spacing—size of the total array. The features of a DNA microarray are usually tens of micrometers in size with a spacing on the order of hundred micrometers. Therefore, miniaturization of such arrays is necessary for applications when scarcity of analytes is an issue. DNA nanoarrays are promising lower analyte volumes due to their decreased feature size and spacing; namely high resolution.

Unfortunately, DNA nanoarrays can only be fabricated by scanning probe microscopy based serial methods which generate each spot individually. [1, 2] To demonstrate SuNS is capable of dealing with the increasing demand to miniaturize DNA arrays in a parallel way, DNA features composed of a few DNA strands is replicated. The faithful printing of feature sizes as small as 14 nm with 70 nm spacing was shown. [3]

References
[1] Demers, L. M., Ginger, D. S., Park, S.-J., Li, Z., Chung, S.-W., Mirkin, C. A. Science 2002, 296, 1836-1838.
[2] Ginger, D. S., Zhang, H., Mirkin, C. A. Angew. Chem., Int. Ed. 2004, 43, 30-45.
[3] Akbulut, O., Jung, J,-M., Bennett, R.D., Hu, Y., Jung, H.,-T., Cohen, R.E., Mayes, A.M. and Stellacci, F. Nano Lett., 2007, 7, 3493–3498.

Collaborators:
Jin-Mi Jung, Ryan D. Bennett, Ying Hu (This was a joint project by the laboratories of Francesco Stellacci, Anne M. Mayes, and Robert E. Cohen at MIT)

Multiplexed Replication of Protein and DNA Arrays

Apart from the capability to cope with features of various sizes, the strength of a printing method emerges from its ability to deal with different types of biomolecules. Coiled-coil peptides are treated analogously to complementary DNA strands due to the molecular recognition between two complementary peptide strands. We also demonstrated the replication of coiled-coil motif peptides through Liquid Supramolecular Nanostamping (LiSuNS). To prove the multiplexing capability of the process, a master made of peptide and DNA features was successfully stamped via LiSuNS as well. [1]

Reference
[1] Laromaine, A.*, Akbulut, O.*, Stellacci, F., and Stevens, M.M. J. Mater. Chem., 2010, 20, 68-70. (*:donates equal contribution)

Collaborators:
Anna Laromaine (This was a joint project between the laboratories of Francesco Stellacci at MIT and Molly Stevens at Imperial College)

Separation Science-The Toolbox: Multiphase Systems (MuPSs)

Density-based Separations

In the Whitesides Group at Harvard University, we have found that through phase separation, certain combinations of water soluble polymers and surfactants form self-assembling gradients in density. The phases in these systems stack according to their density; other physical and chemical properties of the phases are dictated by the chemical composition of each phase. The interface between adjacent phases can be utilized to separate and collect objects based on their density. Using this method, we have fractionated the cells in human whole blood.

Collaborators:
Charles R. Mace, A.J. Kumar, Nathan Shapiro and Abeer Sayed

The Multiphase System (MuPS) in the figure is composed of aqueous solutions of poly(ethylene glycol) (PEG), poly(2-ethyl-2-oxazoline) (PEOZ), poly(vinyl alcohol) (PVA), dextran, and Ficoll. The system is capable of separating a set of six density standard beads. (A) Before phase separation. (B) After phase separation. Upon centrifugation each bead is localized at the corresponding interface.

Separation Science-The Toolbox: Multiphase Systems (MuPSs)

Dynamic Separations
Under centrifugal force, the differences in the hydrodynamic behavior of objects with different shape, size, and density can be used to separate objects which are much denser than phases of MuPSs. In a three phase system, we have separated the reaction products (rods, spheres and bigger particles) of a gold nanorod synthesis.

Collaborators:
Charles R. Mace, A.J. Kumar, Ramses V. Martinez and Zhihong Nie.

(A) A three-phase system separated the reaction products of a gold nanorod synthesis. (B) TEM images of suspension of nanoparticles (suspension of NP) and samples collected from the layers as shown in (A). The scale bar in each image corresponds to 200 nm.