Styliani Constas

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Styliani Constas

Styliani Constas

Contact Information

Title: Professor
Office: Rm 071 ChB,
Lab: Rm 068 ChB,
Phone (Office): ext 86338
E-mail: sconstas@uwo.ca

Physical & Analytical Teaching Division

Theory and Computation

Theoretical and Computational Physical Chemistry; Molecular Simulations; Soft matter; Modelling of reactivity in aerosols; Modelling of ion-biomolecule interactions

Education

B.Sc. (National and Kapodistrian University of Athens, Greece); M.Sc. (Queen's University, Kingston, Canada); Ph.D. (University of Toronto); Marie Curie Fellow (AMOLF, Amsterdam, The Netherlands)

Awards

Fulbright Canada Research Chair in Climate Change, Air Quality, and Atmospheric Chemistry, University of California, Irvine, 2022-2023
Department of Chemistry (UWO) Research Excellence Award
Marie Curie TMR Fellowship (AMOLF, Amsterdam, The Netherlands)
Visiting Fellow at Lucy Cavendish College, University of Cambridge, UK
Marie Curie International Incoming Fellowship Award, Department of Chemistry, University of Cambridge, UK
Premier's Research Excellence Award
Accelerator Grant for Exceptional New Opportunities (AGENO), NSERC

Research

studies the stability of chemical and biochemical systems by investigating their dynamics using computer modelling. We employ and develop Molecular Dynamics and Monte Carlo techniques to study rare event dynamics. These critical events, that are usually identified with the transition state of the process, are a bottle-neck in the simulations of a variety of systems of chemical and biological interest. Using these methods we examine conformational changes of macromolecules such as proteins and nucleic acids in solution, stability of non-covalently bound complexes of proteins, nucleic acids and other macromolecules, chemical reactions in solution, disintegration mechanisms of charged nanodrops. Depending on the dimension of the system we study and the question we examine, we employ atomistic, continuum and multi-scale modelling.

Chemistry in small volumes - From droplets to biological cells

Nano and microconfining environments, such as droplets in any medium and biological assemblies, crevices in corroding metals as well as interfaces and compartments in biological cells are subject to distinct chemistry in contrast to their bulk solution counterparts. The overarching goal of my research program is to push the boundaries of chemistry by enhancing our understanding of chemical mechanisms within small-scale volumes, particularly in systems with linear dimensions at the nano- and micro-scale levels and at interfaces. We aim to uncover universal principles and patterns governing chemistry within these confined spaces and intricate geometries. To achieve that we have developed a suite of computational methods that include multi-scale, atomistic and mathematical modelling, and numerical solutions of electrostatic equations. An immediate outcome of our research is to explain physical and chemical phenomena, offer guidelines for experimental protocols and insights in data interpretation. This would, in turn, increase the capabilities of analytical chemistry techniques, namely mass spectrometry, ensuring reliable detection of surface composition in atmospheric aerosols, surface reactivity, and biological assemblies.

Droplets are often charged due to the presence of ions and macroions (e.g. nucleic acids, proteins and other polyelectrolytes). As it has been demonstrated in recent electrospray-collision beam experiments, the droplets provide a distinct environment for chemical reactions where certain reactions accelerate by orders of magnitude relative to their bulk counterparts. For this reason, chemistry in the small volume of the droplets may be the future ``beaker'' of chemistry. From another perspective, a cell and certain of its organelles share common features with a droplet. These features include confinement, crowding and shape fluctuations. Because of these commonalities, a droplet may be used as a model of a biological cell.

Considering the significant role of droplets in atmospheric chemistry, biology, technology and analytical chemistry, we discover the ion and macroion (protein, nucleic acids)-droplet interactions, the origin of the acceleration of chemical reactions and the reactivity of atmospheric aerosols.

Macromolecule-ion interactions

Macromolecules play a key role in technology and chemistry. However, their computations are challenging due to the extremely long relaxation times present in high density systems and long single chains such as proteins, polysaccharides and nucleic acids. These systems cannot be simulated using conventional Molecular Dynamics and Monte Carlo methods. We develop biased Monte Carlo methods [Consta et al.: "Recoil growth: An efficient simulation method for multi-polymer systems". The Journal of Chemical Physics, 110(6), 3220-3228 (1999); Recoil growth algorithm for chain molecules with continuous interactions. Molecular Physics, 97(12), 1243-1254 (1999)] that allow for rapid equilibration of these complex systems. We apply these methods in the study of macromolecule-ion/proton interactions in the gaseous phase, on surfaces and solutions. Applications of these studies are found in mass spectrometry and in the chemistry and biochemistry of polyelectrolytes.

Collaborative projects

In collaboration with experimental groups that study the chemistry of atmospheric aerosols we examine the intricate molecular details of mass spectrometry methods used in the analysis of these systems.