Presenter 1: Martina Setz (PhD, MD Group, SCMB)

Title: Scale Validation of GROMOS Force Fields for Biomolecular Simulations

Abstract: The relationship of protein structure, dynamics, and function at an atomic level is often investigated using molecular dynamics simulations (MD). A so-called force field, which consists of a set of empirically derived parameters to describe the interatomic interactions, lies at the heart of any MD simulation. To increase the reliability of a simulation conducted with a force field, it is developed to match experimental results as closely as possible. The GROMOS force fields are parameterised to match thermodynamic properties, such as solvation free energy, heat of vaporisation, and density of small molecules (e.g. amino acid side chains) as well as spectroscopic properties of whole biomolecules, such as torsion angle distributions and NOE violations as collected from NMR experiments. Typically, the validation of the previous GROMOS force fields included the thorough investigation of only a few proteins and peptides (and nucleic acids),  hence lacking a solid statistical basis for their validation. We have compiled a set of 60 proteins, 5 fast-folding peptides, and 3 beta-peptides to alleviate this problem. With the analyses conducted so far, we can show that the most recent GROMOS force fields (54A7 and 54A8) are superior to their successors (53A6, 45A4) in terms of protein stability and dihedral angle distributions.

Presenter 2: Dr Hongwei Zhang (ECR, Yu Group, AIBN)

Title: Surfactant-Free Assembly of Mesoporous Carbon Hollow Spheres with Tuneable Structural Parameters and Morphologies

Abstract: Mesoporous carbon hollow spheres (MCHS) have wide applications, including catalysis, absorption, and energy storage/conversion. A big challenge in materials science is surfactant-free synthesis of hollow carbon nanoparticles with tunable mesostructures. Herein we report a new surfactant-free sequential heterogeneous nucleation pathway to prepare mesostructured hollow carbon nanoparticles. This strategy relies on two polymerizable systems, i.e. resorcinol-formaldehyde and tetraethyl orthosilicate (TEOS), each of which undergoes homogeneous nucleation and particle growth. By controlling the polymerization kinetics of two systems when mixed together, sequential heterogeneous nucleation can be programmed leading to monodispersed and MCHS with controllable mesostructures (bi- and triple-layered) and rich morphologies (invaginated, intact and endo-invaginated spheres). By simply changing the silica precursor to tetrapropyl orthosilicate (TPOS), a co-condensation process between the in situ generated silica primary particles and the polymer oligomers is regulated, leading to monodispersed MCHS with adjustable pore sizes from micropores to 13.9 nm. These particles not only show potentials in biomedical applications, but also present excellent performance for electrochemical double-layer capacitors with high capacitance, excellent rate capability, and outstanding cycling stability.