In this work, we designed and synthesized a new kind of nanobeacon, built with cubic-shaped iron oxide nanoparticle (IONC), generation 4 poly(amidoamine) dendrimer (G4 PAMAM), triblock copolymer Pluronic P123 (P123) and HSP90α mRNA-specific molecular beacon (HSP90-MB), to implement HSP90α mRNA quantitative detection and efficient downregulation in living cells and to enhance T2-weighted MR imaging in a tumor model (Figure 1). Here, HSP90AA1 is linked to neoplasm.