Peptide nucleic acid oligonucleotide syntheses were carried out using a 2-mmol cycle on an Expedite 8900 synthesizer (Applied Biosystems, Foster City, CA). For the preparation of peptide-PNA conjugates, the FMOCprotected peptide TNT sequence was synthesized and left on the resin by PepSyn Ltd with the N-terminal FMOC left intact. The resin was extracted from the peptide synthesizer column and was then loaded into the Expedite synthesizer column (2 mmol per column). PNA synthesis was carried out as normal on the preloaded resin. The yield of each purified conjugate was in the range 4.3-32 OD 260 , which corresponds to a 1.5-21% yield based on the 2-mmol synthesis scale. The sequences and yields of the TNT-PNA probes are shown in Table 2 .