I joined ISIS as an instrument scientist for the neutron backscattering spectrometers IRIS and OSIRIS‚ in 2007. In November 2019, I took over as Group Leader of the Molecular Spectroscopy Group, which houses both basckattering spectrometers, as well as TOSCA (vibrational spectrometer) and VESUVIO (high energy). Prior to this I was an instrument scientist on the High Flux Backscattering Spectrometer at the NIST‚ Center for Neutron Research in MD, USA. A chemical engineer by training at Imperial College London, I have concentrated my scientific career on understanding the behaviour of macromolecules, throughout my PhD at Imperial, my postdoc at Pennsylvania State University and my time at neutron facilities.
My research focuses on the exploitation neutron scattering techniques, in particular neutron spectroscopy, to better understand the Dynamics in Soft Condensed Matter and Biophysical systems. Neutron scattering is an ideal tool since it is non-destructive, neutrons are highly penetrating, and probes atomic/molecules lengthscales and timescales which overlap with that from simulations.
Specific areas of interest include:
- Cryopreservation - The mechanism underlying stabilization is still not well understood.Trehalose, a disaccharide found in organisms that survive desiccation over long periods of time, is known to have a stabilizing effect on biologicals and is used for the long-term storage of membranes, proteins and cells. For membranes, trehalose lowers the melting temperature of the bilayer preventing leakage during freezing and drying of cells. For low temperature storage, glycerol may be a better candidate.
- Dynamics of biological macromolecules - The dynamics of biological macromolecules span many orders of magnitude, and in addition to their structure play a key role in their function in living organisms. Understanding the dynamics of functional groups in protein as a function of hydration, pH and environment in general will help us understand how proteins function. In particular membrane proteins represent a important research challenge, since they participate in many life processes. Protein-protein interactions, lipid-protein interaction, lipid matrix behavior are all integral parts; an understanding of the dynamics in these systems in combination with structural studies should give us a complete picture.
- Functional polymers - In order to create new materials with specific properties, we often rely on blending of two polymers or making nanocomposites. These have a very broad range of applications given their enhanced properties, but also provide very interesting fundamental science, that on confinement on the nanoscale. For example, blending two thermodynamically miscible polymers with vastly different glass transition temperatures (Tg) creates dynamical immiscibility, or understanding the reduction of Tg with the addition of nanoparticles similar to that observed in thin films.
You can read some reviews in the field:
J. S. Gardner, G. Ehlers, A. Faraone, V. Garcia Sakai, High-resolution neutron spectroscopy using backscattering and neutron spin-echo spectrometers in soft and hard condensed matter, Nature Review Physics 2 (2020) 103-116.
V. García Sakai, C. Alba-Simionesco, S.-H. Chen [Eds.], Dynamics of Soft Matter, Springer, New York, 2012
V. García Sakai and A. Arbe, Quasielastic neutron scattering in soft matter, Current Opinion in Colloid & Intefrace Science 14 (2009) 381-390
Current Positions of Responsibility
Vice-chair of the Scientific Advisory Council for the European Spallation Source (2021-2022). Previously member of the ESS SAC (2020) and Chair of the Scientific and Technical Advisory Panel for Spectroscopy for the European Spallation Source (2016-2020).
Member of the STFC Life Sciences and Soft Materials Advisory Panel (2019-2021)
Member of the Scientific Advisory Board for the Heinz Maier-Leibnitz Zentrum (MLZ) (2021-2025)
Member of the board of directors of the Sociedad Española de Técnicas Neutrónicas (2006‐present)
Member of the Neutron Spectroscopy Advisory Commiittee at the Kurchatov Institute (2015-present)
Former Member of the Institute Laue-Langevin's Scientific Council (2014-2020)
Former Member and Chair of a number of proposal and instrumentation review panels at neutron international facilities (NCNR-NIST, J-PARC, SNS-ORNL, STS-ORNL, MLZ, ILL)
Chair and co-chair of the Gordon Research Conference in Neutron Scattering (2021-postponed and 2019, respectively). Positions in a number of subject related conference organising committees.
Director (and lecturer) of the Oxford School of Neutron Scattering (2013-present)
PhD Co-Supervisor of Yuanxi Yu (with Prof. Liang Hong, Shanghai Jiao Tong University, China (2019-2023)
Former lecturer in a number of international school on neutron scattering and co-supervision of PhD students.