Nanoparticle Systems for Cancer Phototherapy: An Overview

Abstract

Photodynamic therapy (PDT) and photothermal therapy (PTT) are photo-mediated treatments with different mechanisms of action that can be addressed for cancer treatment. Both phototherapies are highly successful and barely or non-invasive types of treatment that have gained attention in the past few years. The death of cancer cells because of the application of these therapies is caused by the formation of reactive oxygen species, that leads to oxidative stress for the case of photodynamic therapy and the generation of heat for the case of photothermal therapies. The advancement of nanotechnology allowed significant benefit to these therapies using nanoparticles, allowing both tuning of the process and an increase of effectiveness. The encapsulation of drugs, development of the most different organic and inorganic nanoparticles as well as the possibility of surfaces’ functionalization are some strategies used to combine phototherapy and nanotechnology, with the aim of an effective treatment with minimal side effects. This article presents an overview on the use of nanostructures in association with phototherapy, in the view of cancer treatment.

Research Progress of Photothermal Nanomaterials in Multimodal Tumor Therapy

“…The photothermal conversion phenomenon in gold nanoparticles (GNPs) is based on the collective oscillation of free electrons on the surface of GNPs under electromagnetic radiation. The local area around GNPs is heated by electronic excitation and relaxation, which leads to the destruction of tumor tissue ( 72 ). At present, several gold nanomaterials with unique size and morphology have been developed, including nanorods, nanospheres, nanostars, nanocages, and nanoshells, among others.…”

“…Zinc oxide nanomaterials can appear in one-dimensional ( 121 ), two-dimensional ( 122 ), and three-dimensional ( 123 ) structures, providing one of the greatest assortments of particle structures among all known materials ( 124 ). Thus, zinc oxide is a potential alternative for PTT ( 72 ). Deng et al ( 37 ) prepared multifunctional nanoparticles (Z@CD/P) using ZnO@CuS as the carrier, as well as β-cyclodextrin (β-CD) modified by 2,3-dimethyl maleic anhydride (DMA) (β-CD-DMA), and mPEG-NH 2 modified by DMA (PEG-DMA) to increase stability.…”

“…Manganese oxide nanomaterials have great potential as PTAs and signal contrast agents for traditional PTT because of their excellent T1-weighted contrast signals, low cytotoxicity, and high PCE ( 72 , 125 ). Liu et al ( 126 ) proposed for the first time that ultra-thin manganese dioxide nanosheets have pH and redox responses as well as T1-weighted magnetic resonance imaging capabilities.…”

“…It has been found that MCNs have a unique structure that can load a large number of hydrophobic drugs as well as excellent biocompatibility, which makes them an effective drug carrier ( 147 , 148 ). In addition, MCNs have high efficiency in converting NIR laser energy into thermal energy and can be used in tumor PTT ( 72 , 149 ). Xu et al ( 45 ) designed polyethylene glycol-graft-polyethylenimine (HPP)-modified HCNs as NIR-II responsive PTAs.…”

Special Issue: Application of Nanomaterials in Biomedical Imaging and Cancer Therapy

“…Pivetta et al reviewed the nanoparticle systems for photodynamic and photothermal therapy [ 5 ]. They highlighted the technical developments of drug encapsulation and surfaces’ functionalization of organic- and inorganic-based nanoparticles to improve the effectiveness of phototherapy.…”