Cyclic peptide nucleic acid (PNA) can be formed from linear alternating D- and L- peptides linked cyclically. Self-assembling tubular structures formed by hydrogen bonding of the cyclic PNA backbone have been reported. These tubular structures were described to have controlled diameters by alternating the number of peptides in the linear chain. Lengths of the tubular structures could not be controlled due to spontaneous hydrogen bonding between the backbones. We propose a synthesis for a monomer and cyclic PNA that can hydrogen bond the side chains by Watson-Crick base pairing to form nanotubes whose lengths may be controlled by varying the ratio of cyclic PNAs in solution. Synthesis schemes for a monomer capable of Watson-Crick base pairing from both top and bottom of the ring is proposed using standard organic syntheses. This monomer will be used to synthesize cyclic PNA with eight of the monomers by solid phase synthesis. Formation of nanotubes made from the cyclic PNA can be monitored by atomic force microscopy. Nanotubes with a controlled length have practical uses when applied to biological systems. A nanotube can act as a transmembrane ion channel and potentially may be used for drug delivery to specific cells.