Hybrid gold nanoparticle-quantum dot self-assembled nanostructures driven by complementary artificial proteins

International audienceHybrid nanostructures are constructed by the direct coupling of fluorescent quantum dots and plasmonic gold nanoparticles.The self-assembly is directed by the strong affinity between two artificial α-Repeat proteins that are introduced in thecapping layers of the nanoparticles at a controlled surface density. The proteins have been engineered to exhibit a highmutual affinity, corresponding to a dissociation constant in the nanomolar range, which is conferred to the proteinfunctionalizedquantum dots and gold nanoparticles. Protein-mediated self-assembly is evidenced by Surface PlasmonResonance and gel electrophoresis. The size and the structure of colloidal superstructures of complementary nanoparticlesis analyzed by transmission electronic microscopy and small angle X-ray scattering. The size of the superstructures isdetermined by the number of proteins per nanoparticle. The well-defined geometry of the rigid protein complex sets a highlyuniform interparticle distance of 8 nm that affects the emission properties of the quantum dots in the hybrid ensembles.Our results open the route to the design of hybrid emitter-plasmon colloidal assemblies with controlled near-field couplingand better optical response