Towards Nanomaterials for Cancer Theranostics: A System of DNA-Modified Magnetic Nanoparticles for Detection and Suppression of RNA Marker in Cancer Cells

Theranostics of cancer using smart biocompatible materials can enable early cancer diagnostics and treatment. Here, we report on a DNA-nanoparticle functional material, which can simultaneously report the presence of an mRNA cancer biomarker and trigger its degradation in cultured cells. The nanodevice consists of two species of magnetic beads, each of which is conjugated with different components of a multicomponent deoxyribozyme (DZ) sensor. The system is activated only under two conditions: (i) in the presence of a specific target mRNA and (ii) when a magnetic field is applied. We demonstrate that delivery of such a system is markedly enhanced by the application of a magnetic field. The system not only fluorescently detects target mRNA in cultured MCF-7 cancer cells, but also induces its downregulation. Thus, the two-component magnetic nanoparticle system has characteristics of a material that can be used for cancer theranostics.