Preparation of DNA capsules cross-linked through NeutrAvidin–biotin interaction

We developed a templating method based on NeutrAvidin–biotin interaction, for the preparation of hollow microcapsules composed of DNA. In this method, porous calcium carbonate microparticles were employed as a sacrificial template and an adsorbent for DNA, and NeutrAvidin was chosen as a cross-linker for biotin-labeled DNA. By using biotin-labeled DNA with a degree of biotinylation high enough to retain a hollow spherical structure, hollow DNA microcapsules were obtained with the same size as the templates after the dissolution of the templates with chelating agents. In addition, the combination biotin-labeled DNA and NeutrAvidin could be applied to layer-by-layer assembled multilayers. Layer-by-layer assembled capsules exhibited the size-dependent permeability of macromolecular solutes. This study suggests that our method would be facile and widely applicable to prepare various polymer capsules.