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Professor |
Professional preparation
Ph.D., University of Ljubljana, Slovenia
Senior Fulbright Scholar: SUNY at Stony Brook, N.Y.
Research interests
Our research in solution theories focuses on colloidal, biopolymeric and electrolyte systems relevant to biophysics and chemical engineering. We have been developing and applying analytic methods and computational techniques based on principles of statistical mechanics. These include molecular and mesoscopic simulations, integral equation theory of liquids, and field-theoretic methods for studies of soft matter and disordered materials. The goal is to explain microscopic mechanisms behind observed macroscopic behaviors to predict new designs or improved conditions optimizing biological function or pragmatic performance of the material.
Our work is often synergistic with experimental groups in respective fields. Systems we have studied include solutions of synthetic and biological polyelectrolytes such as DNA, surfactant self-assemblies, liquid and quenched ionic media and protein solutions. This research has helped elucidate several crucial aspects of solution electrostatics and solvation phenomena that affect the structure and phase behavior of colloidal solutions, including the important role of ion-ion correlations in intercolloidal attraction.
The ability to control or reverse protein aggregation is vital to numerous technological processes in protein solutions and may be the key to prevention of a number of serious diseases. Complementing collaborative experimental work, we have been performing computational studies of molecular mechanisms involved in different stages of aggregation as a competitive process to protein folding.
In recent years, we have been concerned with modeling of interfacial liquids under the influence of confining surfaces, co-solutes, and applied external field. These efforts advance our understanding of solvation forces, and ability to tune materials’ surface thermodynamics for new applications.
Specific salt effects, crucial to solution properties of proteins and other bio-macromolecules, are analyzed by a combination of molecular simulations and analytic integral equation approaches. We are extending these studies to solutions of nanoparticles with ionic ingredients. In view of close relation with physics of ionic colloids, our studies of protein solutions also impact several topics in colloidal theory, including solvation and confinement effects, ion-specificity and multipolar electrostatic interactions.
Recent publications
Updated Feb 2012
C. D. Daub, D. Bratko, A. Luzar, Nanoscale Wetting Under Electric Field from Molecular Simulations, Top. Curr. Chem. 307, 155 (2012).
J. H. Wang, S. Kudesia, D. Bratko and A. Luzar, Computational probe of cavitation events in protein systems, Phys. Chem. Chem. Phys. 13, 19902 (2011).
C. D. Daub, D. Bratko, A. Luzar, Length-Scale Dependence of Hydration Free Energy: Effect of Solute Charge, J. Stat. Phys. 145, 253 (2011).
C. D. Daub, D. Bratko, A. Luzar, Electric Control of Wetting by Salty Nanodrops: Molecular Dynamics Simulations, J. Phys. Chem. C 115, 22393 (2011).
J. Wang, D. Bratko, A. Luzar, Probing surface tension additivity on chemically heterogeneous surfaces: A molecular approach, Proc. Natl. Acad. Sci. 108, 6374 (2011).
C. D. Daub, J. Wang, S. Kudesia, D. Bratko, A. Luzar,The influence of molecular-scale roughness on the surface spreading of an aqueous nanodrop, Faraday Discuss. 146, 67 (2010), featured on issue cover.
C. D. Daub, D. Bratko, T. Ali, A. Luzar, Microscopic dynamics of the orientation of a hydrated nanoparticle in an electric field, Phys. Rev. Letters 103, 207801 (2009).
D. Bratko, C. D. Daub, A. Luzar, Water-mediated ordering of nanoparticles in an electric field, Faraday Discuss. 141, 55 (2009).
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V. Deniz, M. Bostrom, D. Bratko, F. W. Tavares, B. W. Ninham, Specific ion effects: Interaction between nanoparticles in electrolyte solutions. Colloids Surf. A 319, 98 (2008). #
D. Bratko, C. D. Daub, A. Luzar, Field-exposed water in a nanopore: liquid or vapour? Phys. Chem. Chem. Phys. 10, 6807 (2008). #
D. Bratko, A. Luzar, Attractive surface force in the presence of dissolved gas: A molecular approach. Langmuir 24, 1247 (2008). #
T. Cellmer, D. Bratko, J. M. Prausnitz, H. W. Blanch, Protein aggregation in silico. Trends Biotechnol. 25, 254 (2007), featured on issue cover.#
C. D. Daub, D. Bratko, K. Leung, A. Luzar, Electrowetting at the nanoscale. J. Phys. Chem. C 111, 505 (2007). #
D. Bratko, T. Cellmer, J. M. Prausnitz, H. W. Blanch, Molecular simulation of protein aggregation. Biotechnol.Bioeng. 96, 1 (2007), featured on issue cover. #
D. Bratko, C. D. Daub, K. Leung, A. Luzar, Effect of field direction on electrowetting in a nanopore. J. Am. Chem. Soc. 129, 2504 (2007).
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M. Bostroem, F. W. Tavares, D. Bratko, B. W. Ninham, Ion-Specific Interactions between Pairs of Nanometer Sized Particles in Aqueous Solutions, Prog. Coll. Polym. Sci. 133, 74 (2006).
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D. Bratko, T. Cellmer, J. M. Prausnitz, H. W. Blanch, Effect of single-point sequence alterations on the aggregation propensity of a model protein. J. Am. Chem. Soc. 128, 1683 (2006).
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M. Bostroem, F. W. Tavares, D. Bratko, B. W. Ninham, Specific ion effects in solutions of globular proteins: Comparison between analytical models and simulation. J. Phys. Chem. B 109, 24489 (2005). #
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T. Cellmer, D. Bratko, J. M. Prausnitz, H. W. Blanch, Protein-folding landscapes in multichain systems. Proc. Natl. Acad. Sci. 102, 11692 (2005). #
A. Luzar, D. Bratko, Gas solubility in hydrophobic confinement. J. Phys. Chem. B 109, 22545 (2005).
T. Cellmer, D. Bratko, J. M. Prausnitz, H. W. Blanch, Thermodynamics of folding and association of lattice-model proteins. J. Chem. Phys. 122, 174908 (2005). #
T. Cellmer, D. Bratko, J. M. Prausnitz, H. Blanch, The competition between protein folding and aggregation: Off-lattice minimalist model studies. Biotechnol. Bioeng. 89, 78 (2005). #
F. W. Tavares, D. Bratko, J. M. Prausnitz, The Role of Salt-Macroion van der Waals Interactions in the Colloid-Colloid Potential of Mean Force, Curr. Opinion Coll. Interface Sci. 9, 81 (2004).
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Updated: 03/19/2012 |
