The objective of this work is to develop multifunctional biocompatible nanoparticulate system that can be used both for imaging and therapy. Although several combinations of visualization and therapeutic strategies can be envisioned, the nanoparticles developed in our lab encapsulate near infrared dye and magnetic nanoparticles. Either or both encapsulates can be used for imaging as well as for therapy.

Indocyanine green loaded multilayer magnetic nanoparticles were prepared by thermal decomposition method followed by spontaneous emulsification solvent diffusion. The prepared magnetic nanoparticles were characterized for particle size, size distribution, zeta potential and morphology. The successful coatings of poly lactic-co-glycolic acid and poly (ε) caprolactone polymers on the magnetic nanoparticles were confirmed by atomic force microscopy and fourier transform infrared spectroscopy. The magnetic property of nanoparticles was measured by magnetic susceptibility tester, and the entrapment of indocyanine green the magnetic nanoparticles was calculated. The prepared magnetic nanoparticles were observed to be spherical in shape, 160 � 9 nm in size, with a narrow particle size distribution. The zeta potential was observed to be -12.54 mV. Fourier transform infrared spectroscopy showed peaks at 1760 cm-1 and 1726 cm-1 confirming the successful coating of poly lactic-co-glycolic acid and poly (ε) caprolactone respectively on the magnetic nanoparticles. The effective magnetic movement was found to be 4.98 showing the ferromagnetic nature of the particles. The entrapment efficiency of indocyanine green was found to be 75 % and prepared particles provided aqueous stability to ICG.