LED-activated methylene blue-loaded Pluronic-nanogold hybrids for in vitro photodynamic therapy.

In this work we introduce a new class of multifunctional photodynamic agents based on the coupling of photosensitizer molecules with noble metal nanoparticles, which can be efficiently activated under low light intensity. The favourable modification of the photophysical properties of methylene blue (MB) in MB-loaded Pluronic-nanogold hybrids (Au-PF127-MB) increases the probability of singlet oxygen generation, which in turn allows the use of a light emitting diode (LED) irradiation source instead of commonly used, more invasive lasers. In this regard, Au-PF127-MB treated human lung carcinoma cells (HTB 177) were irradiated at different light doses, using a 660 nm LED source, the results indicating a dose dependent therapeutic effect, decreasing the cell viability down to 13%. Owing to their effectiveness, biocompatibility and integrated imaging and therapeutic functionalities, Au-PF127-MB could represent an important development in the field of biophotonic applications.