Visualizing Low-Level Point Mutations: Enzyme-like Selectivity Offered by Nanoparticle Probes

Highly selective DNA probes prepared by functionalizing gold nanoparticles with nonionic morpholino oligos are described. The nanoparticle probes offer enzyme-like selectivity based simply on hybridization reactions, allowing visual detection of a perfectly matched target within a large excess (>1000-fold) of single-base-mismatched DNA.