Photodynamic therapy: Innovative approaches for antibacterial and anticancer treatments

Abstract

Photodynamic therapy is an alternative treatment mainly for cancer but also for bacterial infections. This treatment dates back to 1900 when a German medical school graduate Oscar Raab found a photodynamic effect while doing research for his doctoral dissertation with Professor Hermann von Tappeiner. Unexpectedly, Raab revealed that the toxicity of acridine on paramecium depends on the intensity of light in his laboratory. Photodynamic therapy is therefore based on the administration of a photosensitizer with subsequent light irradiation within the absorption maxima of this substance followed by reactive oxygen species formation and finally cell death. Although this treatment is not a novelty, there is an endeavor for various modifications to the therapy. For example, selectivity and efficiency of the photosensitizer, as well as irradiation with various types of light sources are still being modified to improve final results of the photodynamic therapy. The main aim of this review is to summarize anticancer and antibacterial modifications, namely various compounds, approaches, and techniques, to enhance the effectiveness of photodynamic therapy.

Multifunctional protein-based self-assembled nanoplatform: overcoming hypoxic tumor microenvironment for enhanced imaging-guided photodynamic therapy

“…26 To address these challenges and boost the selectivity and efficiency of PDT, there is an urgent need for the development of innovative PSs and strategies. 27 The emergence of supramolecular self-assembly nanotechnology has provided an opportunity to propel the further development of efficient PDT. [28][29][30] Through the orderly arrangement of various components, it can not only achieve multifunctional integration in one platform with increased stability but also allows for enhanced control over the physicochemical properties of the assembled nanostructures, thus improving therapeutic efficacy.…”

“…26 To address these challenges and boost the selectivity and efficiency of PDT, there is an urgent need for the development of innovative PSs and strategies. 27…”

Dithiocarbazate–Zn(ii) complexes for photodynamic therapy and chemotherapy against lung cancer

“…15 In photodynamic therapy, photosensitizers are accumulated in tumors and generate reactive oxygen species (ROS) upon irradiation with light, thereby inducing tumor regression. 16 After photodynamic therapy, a series of therapeutic effects occur, such as damage or permeabilization of the tumor vasculature, tumor cell apoptosis, tumor cell necrosis, and immune system response activation to induce tumor regression. 17 Moreover, photodynamic therapy can be repeated on the same site without a decrease in efficacy.…”

Silver Nanoparticle-Loaded Titanium-Based Metal–Organic Framework for Promoting Antibacterial Performance by Synergistic Chemical–Photodynamic Therapy

“…The key to this strategy is to search for a photosensitizer (PS) for the effective production of ROS under suitable light irradiation. Although various organic photosensitizers (e.g., porphyrin and phthalocyanine) and nanophotosensitizers (e.g., metal oxide nanoparticles, quantum dots, carbon dots, and semiconductors) , have been extensively exploited as antimicrobial agents via aPDT, the ROS generation efficiency is still not satisfactory, largely hampering the board applicability of aPDT in clinical treatments . Another useful antibacterial therapy is chemotherapy by silver nanoparticles (Ag NPs), which have been proved to be effective antimicrobial agents with broad-spectrum antimicrobial activity and are not likely to develop drug-resistance. , However, the easy self-aggregation and the hard recovery of Ag NPs severely limit their biomedical applications .…”