Abstract
I. To develop efficient and biosafe techniques for intracellular labeling with ultrasmall superparamagnetic iron oxide (USPIO) particles for cellular magnetic resonance imaging (MRI) is crucial for the development of successful stem-cell therapy. In this study we develop a novel system composed of RBC-derived vesicles (RDVs) for efficient delivering of USPIO particles into human bone marrow mesenchymal stem cells (MSCs) for cellular MRI in vitro and in vivo. The RDVs are highly biosafe to their autologous MSCs as manifested by cell viability, differentiation, and gene microarray assays. The data demonstrate the potential of RDVs as intracellular deliverers for biomedical applications. II. In the last decade, a series of reports have shown that DNA can be used to fabricate not only two-dimensional (2D) nanopatterns, but also three-dimensional (3D) polyhedra. A variety of applications of 3D DNA assemblies have been proposed; according to tensegrity principle that triangular faces will lead to rigid structures, DNA icosahedra would be expected to be rigid and resistant to deformations, hence could potentially serve as nanocages. Up to now, drug encapsulation and intracellular delivery using DNA nanoparticles remain a challenge. Here, we create a distinct five-point-star motif and aptamer-conjugated six-point-star motif using well-used primer sequences to intermolecularly construct DNA icosahedra as a nanocarrier for doxorubicin. Aptamer-conjugated doxorubicin-encapsulated DNA icosahedra (Doxo@Apt-DNA-icosa) show an efficient and specific internalization for killing epithelial cancer cells.