Addressable bipartite molecular hook (ABMH): immobilized hairpin probes with sensitivity below 50 fM.

Sensitivity and specificity of nucleic acid binding probes immobilized on solid supports are essential features of microarrays. Whereas conventional biochips apply nonquenched linear probes (cDNA, oligonucleotides), hairpin structures containing a fluorophore-quencher system comprise important prerequisites required for ideal transcriptional probes. We describe here the generation of addressable bipartite molecular hook (ABMH) probes and the characterization of their performance analyzing biological and clinical samples, also in comparison to linear oligonucleotide arrays. ABMH can be immobilized subsequent to reaction with the target sequence or the reaction carried out directly with the immobilized probe; target sequences are recognized with excellent sensitivity, specificity, and a detection limit below 50 fM. Due to excellent sensitivity and specificity, ABMH represent ideal candidates for the nonamplified microarray-based detection of low abundance nucleic acids, e.g., required in diagnostic assays.