The internal structure of the aggregates was further analyzed, based on the position of the Bragg reflections in the SAXS curves. The peaks were indexed with their corresponding hkl Miller indices corresponding to a 3-dimensional hexagonal-closed packed (hcp) structure. The lattice constants, calculated with (Eq. 6 and (Eq. 7, are a= 28.5 nm and c= 40.9 nm. The a-lattice constant in the hcp structure depicts the distance between the occupied positions in a layer and should correspond to the diameter of the AP205 VLP. The diameters from the SAXS and DLS reported above are in reasonable agreement with the a-lattice constant given the physical difference in the methods and the complexity of defining reflection planes in the core-shell particle assembly with adsorbed pMETAC.