DNA Surface Functionalization and Core Crosslinking of Diblock Copolymer Core-Shell Nanoparticles

We describe the synthesis, preparation and characterization of functional diblock copolymer nanoparticles (NPs). Stable, water-soluble, 100 nm-diameter poly(ethylene glycol)-block-poly(styrene) (PEO-PS) NPs encapsulating hydrophobic polystyrene homopolymers were prepared using the flash nanoprecipitation process in a multi-inlet vortex mixer (Johnson and Prud'homme, 2003). We have successfully modified the terminal functional group of the hydrophilic chain and have introduced single-stranded DNA molecules onto the corona of the nanoparticles via azide-alkyne cycloaddition (click chemistry). These “triblock” nanoparticles were characterized using dynamic light scattering (DLS) and UV spectrophotometry indicating that a dense coating of DNA was added to the particles. By varying the length of the DNA and placing these particles in a porous matrix in an electric field, we are currently attempting to estimate the forces that hold the nanoparticle core together. In separate work, we are investigating the ability of a novel set of photoactivatable crosslinkers to stabilize the cores of PEO-PS nanoparticles for enhanced thermal and solvent stability. We have synthesized a series of aryl azide cross-linkers of different sizes and functionality and encapsulated them into the core of nanoparticles via flash nanoprecipitation in order to study their cross-linking efficiency.