Research > Immunestimulators based on bacterial DNA and their incorporation on nanoparticle carriers

Single stranded DNA immune stimulators of bacterial origin, oligodeoxinucleotides (ODNs), are one of the most promising potential adjuvants in vaccination. New generation vaccines with safe but weakly immunogenic antigens are formulated together with carriers and/or adjuvants to induce the desired immunological response. The use of nanoparticles (NP) as carriers for vaccines, also known as nanovaccinology, is a promising new area, which requires further understanding and development. Inorganic particles have shown potential as carriers and are also extremely biocompatible. The successful integration of adjuvant and the carrier into the vaccine carrying nanosystem requires the fundamental understanding of the surface chemistry at the inorganic/bioorganic interface. The aim of this project is to combine DNA immune stimulators and inorganic nanoparticles in a drug delivery system and it builds upon an interdisciplinary collaboration between academic institutions including.

• synthesis of NPs, specifically zirconia@silica core@shell NPs
• charaterisation of their surface chemistry of the NPs and their interaction with ODN molecules by physicochemical methods (TEM, DLS, XRD, NMR, zeta potential measurements, FT-IR)
• evaluation of the biological properties of the NP-ODN preparations including
• stability in biological fluids
• in vitro immune response in dendritic cells and macrophages
• toxicology on hepacytes. 

These findings will provide an increased understanding of the structural features of DNA immunestimulators and their interactions with inorganic NP carriers and thus will enable rational design of drug delivery platforms. Collaboration: Prof. Stefaan De Smedt, Ghent Research Group for Nanomedicine, Pharmaceutical Faculty, Ghent University, Belgium

In addition to the conception of the project, my specific interest is the exploration of the interactions and surface properties of the resulting vaccine nanoplatform at the molecular level using solution state NMR spectroscopy and molecular modelling.
The methodology used in the project involves techniques for 1) structure determination of DNA, 2) characterisation of NP surfaces by NMR spectroscopy and 3) modelling of DNA-NP systems.

1. Structure calculation of DNA using NMR spectroscopy and molecular modelling relies on the collection of geometric descriptors that can be either used directly as restraints in a structure determination protocol or used to validate Molecular Dynamics (MD) simulations. Collaboration: Prof. Frauke Gräter, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
2. The NMR spectroscopy  proved very effective in characterizing the surface chemistry of various nanoscale particles. These methods primarily include quantitative NMR, diffusion NMR (Diffusion Ordered Spectroscopy, DOSY) and Nuclear Overhauser Effect (NOE) spectroscopy, which can be used to characterise ligand shell composition, ligand density, the size and the structure of the complex and the relative binding strengths of the ligands. Collaboration: Prof. José C. Martins, Department of Organic and Macromolecular Chemistry, Ghent University, Belgium
3. Development of zirconia-biomolecular force field for MD simulations. Collaboration: Prof. Hendrik Heinz, Colorado University, Boulder, USA