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Probe design is a critical parameter in successful DNA and RNA target detection. In this proof-of-concept study, we evaluated the single-base mismatch recognition power of surface immobilized and self-assembled stem-loop hairpin DNA oligonucleotide probes modified to contain locked nucleic acid residues (LNA-HP). The stiffness change in conjunction with the stem opening of the interfacial molecules before and after hybridization led to clear variations of the overall film thickness or miniaturized nanospot height, which could be directly measured using an atomic force microscopy (AFM) nanolithography technique. Particularly, LNA-HP achieved highly differentiable readouts between perfectly complementary and singly mismatched targets (discrimination ratio as high as 2 to 3), outperforming the selectivity of its linear and hairpin counterparts with no LNA modification. 10.1021/ac902665c

Propargyl bromide (Br-C[H.sub.2]C=CH) was used as a precursor to generate [C.sub.3][H.sub.3] fragments on Ag(111) surface under ultrahigh vacuum conditions to understand the bonding and reactivity of [C.sub.3] species which include propargyl (M-C[H.sub.2]C=CH), allenyl (M-CH=C-C[H.sub.2]), and acetylide (M-C=CC[H.sub.3]) forms. The results showed that [1,3]-hydrogen shifts and [1,3]-sigmatropic rearrangement play mechanistically significant role in [C.sub.3][H.sub.3] heterogeneous model system.

Reactive acetylide intermediates are brought forth and identified on a clean Ag(111) surface. Results reveal that the acetylide moieties self-couple at approximately 200 K above room temperature, reflecting a much slower reaction rate against vinyl-vinyl or alkyl-alkyl coupling on the same surface.