Engineering discoidal polymeric nanoconstructs with enhanced magneto-optical properties for tumor imaging

The in vivo performance of nanoparticles is affected by their size, shape and surface properties. Fabrication methods based on emulsification and nano-precipitation cannot control these features precisely and independently over multiple scales. Herein, discoidal polymeric nanoconstructs (DPNs) with a diameter of 1000 nm and a height of 500 am are demonstrated via a modified hydrogel-template strategy. The DPNs are obtained by mixing in one synthesis step the constituent polymers - poly(lactic acid-co-glycolic acid) (PLGA) and polyethylene glycol (PEG) climethacrylate - and the payload with magneto-optical properties -5 am ultra-small super-paramagnetic iron oxide nanoparticles (SPIOs) and Rhodamine B dye (RhB). The DPN geometrical features are characterized by multiple microscopy techniques. The release of the Rhodamine B dye is pH dependent and increases under acidic conditions by the enhanced hydrolysis of the polymeric matrix. Each DPN is loaded with similar to 100 fg of iron and can be efficiently dragged by static and external magnetic fields. Moreover, the USPIO confinement within the DPN porous structure is responsible for a significant enhancement in MRI relaxivity (r(2) similar to 500 (mMs)(-1)), up to similar to 5 times larger than commercially available systems. These nanoconstructs suggest a general strategy to engineer theranostic systems for anti-angiogenic treatment and vascular imaging. (C) 2013 Elsevier Ltd. All rights reserved.