Surface-attached peptide nucleic acids (PNA) are shown to retain their unique and efficient hybridization properties, reported in solution studies. PNA recognition layers thus offer significant advantages for sequence-specific DNA biosensors, compared to their DNA counterparts. These advantages include significantly higher sensitivity and specificity (including greater discrimination against single-base mismatches), faster hybridization at room and elevated temperatures, minimal dependence on ionic strength, and use of shorter (10-15-mer) probes. Such unique properties and advantages are illustrated in connection with electrochemical detection of the hybridization event using the Co(phen)(3)(3+) redox indicator and a carbon paste electrode transducer. The new capabilities and opportunities afforded by the use of PNA surface probes are discussed.