A versatile method for the preparation of poly-acrylamide derivative functionalized thermo-responsive gold nanoparticles

Abstract: Herein we report the synthesis of a resilient nanosystem based on silica-coated magnetic MnFe2O3 nanoparticles conjugated to fluorescein and PEGylated gold nanorods embedded in polymeric micelles (MnFe2O4@SiO2@GNRs@PMs), for magnetic-photoacoustic-optical triple-modality imaging. The magnetic relaxivity of the nanosystem has been evaluated, revealing high r2/r1 ratios that suggests the effectiveness of the nanosystem as T2-contrast agent. In addition, contrast-based fluorescence imaging has been tested both in vitro and ex vivo, showing that the nanosystem owned the suitable optical properties of fluorescein, with contrast intensities comparable with previously reported results. Finally, photoacoustic, due to gold nanorods, performances of the nanosystem have been evaluated, revealing good linearity between concentration and photoacoustic response in the 25 – 250 nM concentration with irradiation at 690 nm. The results showed a contrast-to-noise ratio (CNR) as high as 60 in a mouse leg subcutaneously injected with the nanosystem. Biocompatibility studies revealed no hemolytic effect induced by the nanoconstruct, revealing the applicability of the studied diagnostic tool for medical studies.