Perspectives and Challenges of Simulations at Bio-materials Interfaces
University of Bremen, Germany
The physical/chemical behaviour of hybrid organic/inorganic interfaces in the focus of this proposal results from a delicate interplay between the electronic or mechanical properties of the inorganic phase and the surface bonding of biological molecules, which may undergo a drastic change of their structure and thus of their functionality upon interaction with the solid. Chemical reactions at the phase boundaries and other processes involving the transfer of electrons or the exchange of ions across the interface characterise uniquely the behaviour of the composite material. Since such effects are not trivial to be predicted a priori, computer modelling offers a viable way to investigate them on the basis of fundamental physical principles, thus complementing and expanding the information obtained by means of experimental techniques.
The investigation of phenomena at hybrid biomaterials interfaces poses so far unresolved challenges to accurate, atomistic computational methods, since it involves dealing with mutually interacting phenomena spanning multiple time and length scales and requiring different levels of precision. In the biological community, deciphering the physics of complex units from motor proteins to ribosomes, from membrane channels to DNA packaging in the cell nucleus, has become possible by the advent of many new technologies to analyze and manipulate molecular systems at highest precision. Combining high-resolution structural analysis with high-performance computing enabled furthermore to simulate how the intrinsic structural movements of biological nanosystems combined with their optical, electrical or mechanical properties control or regulate their functions. Also aided by high-performance computing, new functional hybrid-materials were designed, some of which were inspired by biological systems. Understanding life from its molecular foundation, learning from it for technical applications and investigating how the interactions between living structures interact and the technical world may stimulate novel routes for materials design has become a very attractive field of research these days.
Presently, dynamical simulations of large chemical and/or biological molecules or of surface phenomena must rely on classical molecular dynamics to address the size and time scales relevant for such systems. However, there are some fundamental functions of proteins which require a quantum mechanical description. This includes catalytic reactions in enzymes, photo-induced processes in fluorescent proteins, light-energy conversion reactions in the photosynthesis. The same is true in materials science, where reactive adsorption processes on surfaces have to be described quantum mechanically in order to catch the basic features of the electron dynamics and related reactive chemistry. The level of complexity is increasing even more if the biosystems meet technical surfaces, interact chemically and form new functional units. The particular challenge in describing the dynamics of such hybrid systems involves:
(i) the quantum mechanical description of large molecules interacting with materials substrates,
(ii) combined quantum/classical/continuum descriptions to treat environmental conditions and
(iii) stochastic quantum mechanics combined with molecular dynamics to explore an extended configurational space.
Due to the apparent differences in the methods needed to capture various aspects that dominate physical phenomena at different length scales, the research community still remains divided by traditional boundaries, as e.g. between biology/biophysics and materials science. The major goal of the proposed CECAM-Workshop is to enhance interdisciplinary interactions between the described research fields and in particular to stimulate exchange of methodological computational expertise between pure classical molecular dynamics and coarse graining simulations of large system and quantum dynamical treatments of reactive centers in electronic ground and excited states with or without dissipation. Additionally, the Workshop aims to enhance communication between experiment and theory, which will ultimately help to define the relevant questions and assumptions. Therefore, from the broad range of experienced researchers working in these areas, we are inviting exceptional individuals who have already successfully made this step across traditional boundaries, and from experiment to theory or vice versa.
Lucio Colombi Ciacchi (University of Bremen) - Organiser
Thomas Frauenheim (University of Bremen) - Organiser
Viola Vogel (Swiss Federal Institute of Technology Zurich (ETHZ), Switzerland) - Organiser & speaker