Pluronic-Nanogold hybrids: synthesis and tagging with photosensitizing molecules

The design of polymeric-metal hybrid nanocomposites with multiple functionalities, i.e. from enabling detection and imaging to assisting diagnosis and therapy, is becoming an important research topic in nanomedicine. In this work, Pluronic-Nanogold hybrid nanoparticles (Au-PF127) were successfully prepared in aqueous solution in a single step reaction using Pluronic F127 block copolymer as both reducing and stabilizing agent. The ability of polymer to control the nanoparticle formation and stabilization was systematically investigated by several characterization techniques: UV-Vis absorption, transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential measurements. It was found that polymer concentrations higher than critical micelle concentration (CMC) provide stable nanoparticles even in high molarity NaCl solution. In view of biomedical applications, as prepared Au-PF127 nanoparticles were modified with Methylene Blue (MB) phenothiazinium based photosensitizing drug. Combined surface enhanced Raman scattering (SERS) and fluorescence detection of MB embedded within the polymer shell has revealed the dual functionality of MB-encoded Pluronic-Nanogold hybrids (Au-PF127-MB) to operate under biological conditions as both effective drug carriers and sensitive optical probes.