Gold Nanoparticle-Mediated PhotodynamicTherapy: Emerging Strategies for TargetedCancer Treatment

Abstract

Photodynamic therapy (PDT) is a comparatively gentle form of cancer treatment that uses a photo-sensitizer, light,
and molecular oxygen to reactive oxygen species, inducing targeted destruction for the tumor cells. The combination
of nanotechnology, especially gold nanoparticle (AuNPs), has much higher accuracy and treatment effect of PDT. The
focus of this review is to extend the state-of-art of wearable AuNPs-based PDT, focusing on their physico-chemical
benefits and potential for enhanced cancer treatment. A systematic review of the literature was conducted toward
assessing the relevance to PDT of AuNPs with an emphasis on their surface plasmon resonance, biocompatibility,
and functionalization capabilities. These included AuNPs-based systems, including PEGylated spheres, gold nanorods,
and prostate-specific membrane antigen (PSMA)-targeted conjugates that were investigated as potential vehicles
to effectively carry photosensitizers (PS) and mediators. The review also discusses the stimulated combination of
photothermal therapy (PTT) and PDT. Preclinical in vitro and in vivo studies have shown that AuNPs-coupled PDT can
improve tumor-specific accumulation, enable a selective cytotoxicity while simultaneously reducing non-specific side
effects. The modification of AuNPs enabled effective PSs delivery and accumulation in tumors. Combining PTT and
PDT also improves the therapeutic effect, implying the potential of overcoming some common defects in traditional
PDT. In spite of promising preclinical results, clinical translation is still impeded by limitations related to LPP, suboptimal
biodistribution, and nanoparticle clearance. Overcoming these challenges with sophisticated nanoparticle engineering
and clear regulatory pathways might render AuNPs-mediated PDT a potent, targeted, personalized cancer therapy.