4.4 Nanomaterial modification of porphyrin photosensitizers to enhance light energy capture efficiency for PDT
Nanotechnology has evolved significantly in the last decade. The use of nanomaterial platforms for diagnostics and therapeutics has enabled precise drug delivery to target tissues and increased the effectiveness of anticancer treatments(Ariga et al. 2011; Shi et al. 2017). The enhancement of photodynamic activity of photosensitizers by metal nanoparticles through increased production of1O2 has attracted significant interest(Toftegaard et al. 2008; Zhang et al. 2007). Under light excitation, the surface electrons of metal nanoparticles exhibit collective oscillations (fixed-domain surface plasmon excitations) that can excite enhancement of a series of optical processes near the surface of metal nanoparticles, such as metal-enhanced singlet oxygen production, surface-enhanced Raman scattering (SERS), absorption, and fluorescence and phosphorescence emission intensity(Karolin and Geddes 2013; Zhang et al. 2006). Gold nanoparticles (Au NRs) are capable of enhancing ROS production in PDT applications due to their high biocompatibility, stability, and tunable plasmonic resonance bands(Ferreira et al. 2017; Jang et al. 2011; Schmitt and Juillerat-Jeanneret 2012; Zhao et al. 2012). (Fig. 8)