Metal-DNA nanohybrid structures were prepared by using a combination of metallization and DNA compaction. he DNA were compacted using Pd(II) complexes and then reduced the Pd(II)-coordinated DNA strands to make a unique mosslike hybrid structure. The application of ascorbic acid as a reducing reagent promoted morphological homogeneity of the assembled Pd DNA hybrid materials. The current response, which depended on volume expansion in a cyclic atmosphere exchange, indicates the effectiveness of the DNA template for highly sensitive hydrogen sensors and switches with highly resistant break junctions. The current response of Pd-DNA clusters synthesized by using NaBH4 was also measured. The Pd-DNA clusters synthesized by using NaBH4showed a smaller current change and sensitivity for hydrogen than those by using ascorbic acids.