China
Africa
Explore chapters and articles related to this topic
Diagnostic Test with Targeted Therapy for Cancer: The Theranostic Nanomedicine
Published in Paula V. Messina, Luciano A. Benedini, Damián Placente, Tomorrow’s Healthcare by Nano-sized Approaches, 2020
Paula V. Messina, Luciano A. Benedini, Damián Placente
Absorption of light by molecules could lead to three types of processes: the first one can be applied to chemotherapeutic drug or another agent. In the first case, photochemical reactions of molecules themselves (photolysis of prodrugs which turned into active drugs) or absorption of light by photosensitive molecules generates physical changes into the formulation and thus, the encapsulated drug is released. For the interaction with other agents, the light can also interact with other molecules such as photosensitizers and these activated molecules can interact with oxygen to generate singlet oxygen for producing the death of the tissue (photodynamic therapy). The second process is produced by the emission of light due to radiative relaxation of molecules (fluorescence), and in the last process, light energy can be transferred to other forms due to nonradiative relaxation of molecules, heat (photothermal therapy). We will focus on photodynamic and photothermal therapies; however, some examples of the other processes are also briefly described.
The Role of Nanotechnology in the Treatment of Drug Resistance Cancer
Published in Bhaskar Mazumder, Subhabrata Ray, Paulami Pal, Yashwant Pathak, Nanotechnology, 2019
Sandipan Dasgupta, Anup Kumar Das, Paulami Pal, Subhabrata Ray, Bhaskar Mazumder
Photodynamic therapy (PDT) is a form of cancer treatment that involves the use of photosensitizers as therapeutic agents. In the presence of light, photosensitizers enter a triplet state of excitation. This triplet state of energy is readily transferred to oxygen molecules, which are subsequently converted into reactive oxygen species that are capable of causing cell damage (Konan et al., 2001; Samia et al., 2003; Tang et al., 2004). This method of treatment has high selectivity, since only the cells which are exposed to both the light and the photosensitizer are affected. Photofrin 2, which is a derivative of hematophorphyrin, is the only PDT drug that is approved for clinical use in Canada, the Netherlands, and Japan for the treatment of bladder, lung, and esophageal cancer, respectively (Konan et al., 2001).
Biophotonics
Published in Mohammad E. Khosroshahi, Applications of Biophotonics and Nanobiomaterials in Biomedical Engineering, 2017
Photodynamic therapy (PDT) is an elegant light based oncologic intervention where it uses a light sensitive drug (a photosensitizer), in combination with light of a visible wavelength, to destroy target cells (e.g., cancerous or pre-cancerous cells). PDT is generally used either as a primary treatment (usually in skin conditions) or as an adjunctive treatment alongside surgery, radiotherapy, or chemotherapy. Studies during the 1950s to 1960 revealed not only tumor ablation, but the inter-related ability of photosensitizing agents to fluoresce and demarcate tumors (Lipson and Baldes 1960). However, it was not until the 1970s when Dougherty (1975), working with porphyrin compounds (Hematoporphyrin derivative-HPD), accidentally rediscovered PDT. In contrast to previous iterations, Dougherty created a commercially suitable photosensitizing drug, reliable light sources, and appropriate clinical trials proving the value of PDT to the oncologic community. Some of commercial photosensitizers are: M-tetrahydroxophenyl chlorine (mTHPC) (Foscan), Mono-L-aspartyl chlorine e6 (NPe6), Aminolevulinic acid (ALA), Fotosens. HPD, AL A, MACE, and Foscan can activate at multiple light wavelength from blue to green to red, again allowing for more selective illumination depth based on the individual tumor's depth and location of surrounding critical structures.
Preparation of gelatin nanoparticles by two step desolvation method for application in photodynamic therapy
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Janicy Arantes Carvalho, Alexandro Silva Abreu, Vitória Tonini Porto Ferreira, Erika Peterson Gonçalves, Antonio Claudio Tedesco, Juliana Guerra Pinto, Juliana Ferreira-Strixino, Milton Beltrame Junior, Andreza Ribeiro Simioni
Photodynamic therapy (PDT) is a procedure that uses a photosensitizing drug to apply light therapy selectively target cancer and other diseases [1–3]. It relies on the use of light-susceptible photosensitizers (PS) to generate reactive oxygen species (ROS) and singlet oxygen (1O2), which lead to the death of cells [4,5]. Phthalocyanines are well-studied, highly absorbing organic dyes that are widely used for PDT applications. A common problem, however, for many phthalocyanine photosensitizers is that they are usually hydrophobic and easily form aggregates in aqueous systems, which may dramatically reduce their PDT efficacy and limiting clinical applications. Thus, improving effectiveness of phthalocyanine photosensitizers used in PDT, nanotechnology holds a future promise [6].
Organo-soluble dendritic zinc phthalocyanine: photoluminescence and fluorescence properties
Published in Inorganic and Nano-Metal Chemistry, 2022
Ebru Yabaş, Safacan Kölemen, Emre Biçer, Toghrul Almammadov, Pınar Başer, Mehmet Kul
On the other hand, photodynamic therapy (PDT), which uses photosensitizing drug and visible or near-infrared light (wavelength range of about 630-800 nm is used to achieve the deepest tissue penetration) to destroy cells by photogeneration of one or more reactive oxygen species, is a treatment method for cancer, infections, and other medical applications. Excited photosensitizing drugs can produce cytotoxic reactive oxygen species via type I and/or type II reactions. In a type II reaction, the excited state of the drug can produce singlet oxygen by transferring energy directly to ground-state molecular oxygen. Singlet oxygen, which is highly reactive, causes fatal damage to cells.[63,64]
Synthesis, photophysical and photobiological characterization of BSA nanoparticles loaded with chloroaluminium phthalocyanine by one-step desolvation technique for photodynamic therapy action
Published in Journal of Biomaterials Science, Polymer Edition, 2019
Alexandro da Silva Abreu, Janicy Arantes Carvalho, Agnes Cecheto Trindade, Milton Beltrame Junior, Andreza Ribeiro Simioni
Photodynamic Therapy (PDT) is minimally a non invasive treatment modality for a range of tumors [1–3] and it involves the combination of three key components: oxygen, visible light in specific wavelength and a photosensitizer (PS) to generate reactive oxygen species that are the main responsible for immediate cell death through necrosis or apoptosis [4–6].