Red blood cell membrane camouflaged magnetic nanoclusters for imaging-guided photothermal therapy

Along with intrinsic magnetic resonance imaging (MRI) advantages, iron oxide nanomaterials capable of photothermal conversion have been reported very recently and have again raised great interest in their designs among biomedical researchers. However, like other inorganic nanomaterials, high macrophage uptake, short blood retention time and unfavorable biodistributions have strongly hampered their applications in vivo. To solve these problems, a rational design of red blood cell (RBC) membrane camouflaged iron oxide magnetic clusters (MNC@RBCs) is presented in this paper. Our data show that by simply introducing an "ultra-stealth" biomimetic coating to iron oxide magnetic nanoclusters (MNCs), MNC@RBCs maintain the imaging and photothermal functionalities inherited from MNCs cores while achieving much lower nonspecific macrophage uptake and dramatically altered fate in vivo. MNC@RBCs with superior prolonged blood retention time, preferred high tumor accumulation and relatively lowered liver biodistribution are demonstrated when injected intravenously in mice, leading to greatly enhanced photothermal therapeutic efficacy by a single treatment without further magnetic force manipulation. Our study illustrates a well prepared integration of MNCs and RBCs, exploiting advantages of both functionalities within a single unit and suggests a promising future for iron-based nanomaterials application in vivo.