Unique Diagnostic and Therapeutic Roles of Porphyrins and Phthalocyanines in Photodynamic Therapy, Imaging and Theranostics

Abstract

Porphyrinic molecules have a unique theranostic role in disease therapy; they have been used to image, detect and treat different forms of diseased tissue including age-related macular degeneration and a number of different cancer types. Current focus is on the clinical imaging of tumour tissue; targeted delivery of photosensitisers and the potential of photosensitisers in multimodal biomedical theranostic nanoplatforms. The roles of porphyrinic molecules in imaging and pdt, along with research into improving their selective uptake in diseased tissue and their utility in theranostic applications are highlighted in this Review.

Porphyrin-based cationic amphiphilic photosensitisers as potential anticancer, antimicrobial and immunosuppressive agents

“…2), both synthetic and modified natural products, have almost ideal physical and chemical properties for therapeutic purposes because they are mostly non-toxic without irradiation, but efficiently absorb light in the visible, and some of them even in the near infra-red area, and can generate singlet oxygen. In addition, they have an ability to release fluorescence, which also makes them attractive for diagnostic purposes, and with potential application in theranostics (=diagnostics + targeted therapy) and fluorescence-guided tumour dissection (Allison 2016;Vicente 2001;Josefsen and Boyle 2012).…”

“…Most PSs already have so-called passive selectivity for tumours, but their targeting in cancer therapy can be improved into Bactive targeting^by conjugation to biological macromolecules such as monoclonal antibodies (further discussed below), homing peptides and sugars; these conjugates are known as third-generation PSs (Ethirajan et al 2011;Josefsen and Boyle 2012). The latest development in PDT research is the possibility of using nanomaterials as PS carriers, and, furthermore, delivering PS together with an imaging agent via nanocarriers for selective and targeted PDT (Wang et al 2004;Josefsen and Boyle 2012).…”

“…The latest development in PDT research is the possibility of using nanomaterials as PS carriers, and, furthermore, delivering PS together with an imaging agent via nanocarriers for selective and targeted PDT (Wang et al 2004;Josefsen and Boyle 2012).…”

Removal of Nickel and Vanadium from Heavy Oils Using Supercritical Water

“…These molecules are involved in a number of biologically important roles, including oxygen transport and photosynthesis, and have applications in a number of fields, ranging from fluorescence imaging to medicine 26) . Porphyrins are classified as tetrapyrrolic molecules, with a heterocyclic macrocycle as the center of the molecule, known as porphine 8) .…”

<strong>Effect of Interaction with Micellar Media on Spectral Properties of some Amphiphilic Porphyrins</strong>

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The use of porphyrinic compounds in the field of theranostic nanomedicine, has increased substantially in the recent years due to their special features such as: long wavelength absorption and emission in the spectral region where the biological tissues absorb, a good photodynamic activity, photostability and low in vivo toxicity [1][2][3]. Despite significant advantages, due to the large  conjugate systems, porpyrins easily form aggregates, which have a significantly lower ability for localization at cellular level and consequently decrease the therapeutic effect.

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