Abstract
Based on their enhanced cellular uptake, stability, biocompatibility, and versatile surface functionalization, spherical nucleic acids (SNAs) have become a potentially useful platform in biological applications. It still remains important to expand the SNAs' "toolbox", especially given the current interest in multimodal or theranostic nanomaterials, that is, composites capable of multiple simultaneous applications such as imaging, sensing, and drug delivery. In this paper, we have engineered a nanoparticle-conjugated initiator that triggers a cascade of hybridization reactions resulting in the formation of a long DNA polymer as the nanoparticle shell. By employing different DNA fragments, self-assembled multifunctional SNAs can be constructed. Therefore, using one capped ligand, these SNAs can combine imaging fluorescent tags, target recognition element, and targeted delivery molecules together. Since these SNAs possess high drug loading capacity and high specificity by the incorporation of an aptamer, our approach might find potential applications in new drug development, existing drug improvement, and drug delivery for cancer therapy.