Layer-by-layer assembly of photonic crystal using DNA

Photonic crystal is a key component for optical communication and computing in next generation that having a periodic 3D structure in scale with optical wave length. The major difficulty in practical use of photonic crystal exists in its fabrication process. As an optical component, it must be a defect-free large crystal with waveguide patterns affecting propagation of photons. Many attempts have been made to realize such a crystal, however, low-cost and rapid fabrication of a defect-free large crystal is still a difficult problem. Here, we propose a novel fabrication method combining colloidal crystallization and DNA nanotechnology. In this method, the face-centered lattice made of 1μm polystyrene particle is assembled on a patterned template in a layer-by-layer fashion. In order to control the binding among particles, DNA-gold nanoparticle conjugates (10nm GNP modified with 52-mer DNA) is used. Specific bonding rules between particles and GNPs defined by base sequence of DNA realizes the layer-by-layer growth of the crystal. We have built two-layer crystal by the proposed method and the results show its feasibility. We also found some important factors necessary to improve the quality of the crystal.