Conjugation of Peptides to the Passivation Shell of Gold Nanoparticles for Targeting of Cell-Surface Receptors

We report the preparation of gold nanoparticles (AuNps) functionalized with the peptide-toxin. conantokin G and their selective binding to N methyl D-aspartate (NMDA),receptors recombinantly expressed transfected HEk 293 cells The AuNPs are passivated with aimed self assembled monolayer of omega carboxy and Passivation Systems the alkyl omega amino polyethylene glycol (PEG) thiols. We compare two different passivation systems the alkyl PEG600 system is characterized by a C-11 alkyl system lacks this alkyl-chain. We show that only the alkyl PEG600 passivation system allows selective conjugation of cysteine-terminated peptides to the periphery of the passivation layer via a heterobifunctional linker strategy, In contrast, using,the PEG3000 passivation system, peptides are immobilized both on the passivation layer directly on the gold surface via concurrent place-exchange reaction. We therefore recommend the use of the alkyl PEG600 system to precisely control the number of immobilized peptides on AuNPs. In fact, we show that the number of conjugated peptides per particle can be varying with good control simply by varying the composition of the self assembled, monolayer. Finally, we demonstrate that conjugation of the conantokin G peptide to the solvent exposed interface of the passivation layers results in maximal binding interaction between the peptide functionalized AuNPs and the targeted NMDA receptors on the cell surface Conantokin G coupled AuNP may be used to spatially restrict NMDA receptor blockade on neuronal surfaces.