DNA-gold triangular nanoprism conjugates

Triangular Au nanoprisms were synthesized and purified by adding 3'-alkylthiolated single-stranded DNA (HS-ssDNA) to a solution of nanoprisms. The melting of Au nanoprisms was monitored at 1250 nm, which correspond to the dipole surface plasmon resonance (SPR) of the Au nanoprisms. Transmission electron microscopy (TEM) images of nanoprisms show that the nanoprisms morphology is unaffected by functionalization or melting procedures. The results indicate that at early functionalization time points, the probes bind only to the nanoprism side crystal facets. The experiments with assymetric NP probes also show that selectively functionalized prisms can be isolated at different time points. It is found that Au nanoprisms capped by CTAB can be fully functionalized with an alkylthiolated-DNA moiety, and the ligand-nanoprism conjugate is stable throughout DNA-based melting transitions.