A plasmon-enhanced fluorescent gold coated novel lipo-polymeric hybrid nanosystem: synthesis, characterization and application for imaging and photothermal therapy of breast cancer.

This study reports a hybrid lipo-polymeric nanosystem (PDPC NPs) synthesized by a modified hydrogel-isolation technique. The ability of the nanosystem to encapsulate hydrophilic and hydrophobic molecules has been demonstrated, and their enhanced cellular uptake has been observed in vitro . The PDPC NPs, surface coated with gold by in situ reduction of chloroauric acid (PDPC-Au NPs), showed a photothermal transduction efficacy of ∼65%. The PDPC-Au NPs demonstrated an increase in intracellular ROS, triggered DNA damage and resulted in apoptotic cell death when tested against breast cancer cells (MCF-7). The disintegration of PDPC-Au NPs into smaller nanoparticles with near-infrared (NIR) laser irradiation was understood using transmission electron microscopy imaging. The lipo-polymeric hybrid nanosystem exhibited plasmon-enhanced fluorescence when loaded with IR780 (a NIR dye), followed by surface coating with gold (PDPC-IR-Au NPs). This paper is one of the first reports on the plasmon-enhanced fluorescence within a nanosystem by simple surface coating of Au, to the best of our knowledge. This plasmon-enhanced fluorescence was unique to the lipo-polymeric hybrid system, as the same was not observed with a liposomal nanosystem. The plasmon-enhanced fluorescence of PDPC-IR-Au NPs, when applied for imaging cancer cells and zebrafish embryos, showed a strong fluorescence signal at minimal concentrations of the dye. The PDPC-IR-Au NPs were also applied for photothermal therapy of breast cancer in vitro and in vivo , and the results depicted significant therapeutic benefits.