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)