Polyelectrolyte multilayer core-shell particles in holographic optical tweezers

Assembly of molecules or micro-objects to hierarchically ordered 2D or 3D complex structures is one of the main driving forces in functional nanochemistry, as they expand the applications of individual building blocks. Advanced core-shell particles have the additional potential to be filled with functional guest molecules that can be used for sensing applications, as e.g. biomedical agents, or drug delivery nanocarriers. Among the different core-shell materials, polyelectrolyte capsules, thin hollow polymer shells made from Layer-by-Layer coating of colloidal templates [1] are attractive guest molecule carriers. They can be adapted in shell thickness and diameter. Their sizes are around one micrometer, which is easily accessible for optical control. By using holographic optical tweezers, we arrange them dynamically and reversible. We discuss structuring of capsules on a substrate, capsule fusion, trapping stiffness as well as relevant mechanical properties.