Progress of Nanomaterials in Photodynamic Therapy Against Tumor

Abstract

Photodynamic therapy (PDT) is an advanced therapeutic strategy with light-triggered, minimally invasive, high spatiotemporal selective and low systemic toxicity properties, which has been widely used in the clinical treatment of many solid tumors in recent years. Any strategies that improve the three elements of PDT (light, oxygen, and photosensitizers) can improve the efficacy of PDT. However, traditional PDT is confronted some challenges of poor solubility of photosensitizers and tumor suppressive microenvironment. To overcome the related obstacles of PDT, various strategies have been investigated in terms of improving photosensitizers (PSs) delivery, penetration of excitation light sources, and hypoxic tumor microenvironment. In addition, compared with a single treatment mode, the synergistic treatment of multiple treatment modalities such as photothermal therapy, chemotherapy, and radiation therapy can improve the efficacy of PDT. This review summarizes recent advances in nanomaterials, including metal nanoparticles, liposomes, hydrogels and polymers, to enhance the efficiency of PDT against malignant tumor.

Targeted and Oxygen‐Enriched Nanoplatform for Enhanced Photodynamic Therapy: In Vitro 2D Cell and 3D Spheroid Model Evaluation

“…In this study, a folate-targeted and oxygen-enriched micellar delivery vehicle (M60@PFC-Ce6) was designed to not only transport extra oxygen into cancer cells for improving PDT efficiency, especially in a hypoxic environment, but also provide the specific cancer cell targeting capability to enhance the intracellular accumulation of drugs and penetration depth within the tumor, as illustrated in Scheme 1. This micellar delivery vehicle consists of a fluorinated diblock copolymer, poly(ethyl glycol)b-poly (2,3,4,5,6-pentafluorostyrene) (PEG-b-PFS), Pluronic F127 and folate-conjugated Pluronic F127 (FA-F127) with different formulations to encapsulate both perfluorocarbons (PFD and PFTBA) and photosensitizer chlorin e6 (Ce6). The fluorine moiety in the amphiphilic polymer PEG-b-PFS plays dual roles, including providing the oxygen loading capacity to deliver oxygen molecules and using it as a hydrophobic reservoir to accommodate Ce6 and stabilize the liquid PFCs emulsion.…”

“…Combining them with drug delivery systems can improve their water solubility, prevent their aggregation that leads to loss of photodynamic activity, and accurately accumulate at the target site. [4][5][6] To date, diverse delivery systems with modulated physicochemical properties or sizes have been developed for improving tumor penetration and their photoactivity. However, it is still desirable to develop biocompatible and efficient nanocarriers for enhancing drug penetration and distribution within solid tumors.…”

Hyperbranched Polymers: Recent Advances in Photodynamic Therapy against Cancer

“…In addition, free PSs have the tendency to aggregate in aqueous environments, leading to a decrease in the singlet-oxygen generation efficiency. HB polymers with good biocompatibility and high loading capacities have emerged as promising nanocarriers, protecting PSs from aggregation and degradation, extending their half-life, and improving their tumor accumulation ability [ 33 , 35 ]. Several physical and chemical conjugation strategies have been employed to construct PS–HB polymer nanohybrids for improved PDT efficacy ( Table 2 ).…”

“…These nanocarriers can be either inorganic or organic, including carbon [ 25 ], silica [ 26 , 27 ], gold [ 28 ], metal oxide nanodots [ 29 ], polymeric micelles [ 30 ], nanospheres [ 31 ], liposomes [ 19 ], nanogels [ 32 ], dendrimers [ 33 ], and hyperbranched (HB) polymers [ 34 ]. Many of these nanomaterials have been well developed, and their applications in PDT have been extensively reviewed elsewhere [ 29 , 35 , 36 ]. However, HB-polymer-based nanomaterials possessing many distinct advantages are less discussed compared to other nanosystems [ 37 , 38 , 39 , 40 ].…”

Recent Advances in Photosensitizer Materials for Light‐Mediated Tumor Therapy

“…[3,4,5,6] In recent years, photodynamic therapy (PDT) with controllable body damage, precise targeting ability, favorable biocompatibility and non-invasive feature, has gained more and more attention in the cancer treatment field. [6,7,8] In clinical applications, the procedure of PDT typically involves the prior administration and accumulation of photosensitizers in the targeted lesion, followed by irradiation of the affected region. When irradiated, photosensitizers absorb the light energy and undergo a photochemical reaction in biological environment to generate cytotoxic reactive oxygen species (ROS) to kill cancer cells.…”