Nanodrug applications in photodynamic therapy

Abstract

SummaryPhotodynamic therapy (PDT) has developed over last century and is now becoming a more widely used medical tool having gained regulatory approval for the treatment of various diseases such as cancer and macular degeneration. It is a two-step technique in which delivery of a photosensitizing drug is followed by irradiation of light. Activated photosensitizers transfer energy to molecular oxygen which results in generation of reactive oxygen species which in turn cause cells apoptosis or necrosis. Although this modality has significantly improved quality of life and survival time for many cancer patients it still offers significant potential for further improvement. In addition to the development of new PDT drugs, the use of nanosized carriers for photosensitizers is a promising approach which might improve the efficiency of photodynamic activity and which can overcome many side effects associated with classic photodynamic therapy. This review aims at highlighting the different types of nanomedical approaches currently used in PDT and outlines future trends and limitations of nanodelivery of photosensitizers. PDT -photodynamic therapy; PGA -poly(glycolic acid); PGLA -poly(D,L-lactide-coglycolide); PLA -poly(lactic acid); PS -photosensitizer; PEG -polyethylene glycol; ALA  aminolevulinic acid; m-THPC  5,10,15,20-tetra-(m-hydroxyphenyl)chlorine; m-THPP  meso-tetra(p-hydroxyphenyl); PpIX  protoporphyrin; Hp  hematoporphyrin; Pc4  silicon phthalocyanine; Ig  immunoglobulin; Tf  transferrin; TfR  transferrin receptor; VEGF  vascular endothelial growth factor; EPR  enhanced permeability and retention effect; FRET  fluorescence resonance energy transfer; MRI  magnetic resonance imaging; RES  reticuloendothelial system; ROS  reactive oxygen species; NP  nanoparticle; ND -nanodiamonds; SNP  silica nanoparticle; AMD  age-related macular degeneration; CNV  choroidal neovascularization; PTT  photothermal therapy;

Alterations in dysadherin expression and F-actin reorganization: a possible mechanism of hypericin-mediated photodynamic therapy in colon adenocarcinoma cells

“…Several PS including HYP, are in advanced stages of clinical trials or in the approval phase for the treatment of several malignant and nonmalignant diseases. PDT has been approved in several countries for treatment of bladder, head and neck, lung, breast, esophageal, cervical and pancreatic cancers, but there are still loose ends in its clinical use and treatment of other cancer types, including colon cancer (Paszkoa et al 2011;Yoo and Ha 2012).…”

“…HYP has advantages of minimal dark toxicity, high clearance from the body and high singlet oxygen production. Nevertheless, there are still question marks limiting its clinical use (Paszkoa et al 2011). Depending on the HYP concentration, light dose, incubation time and cell origin, the type of cell death induced by PDT can be altered (Mikeš et al 2007).…”

Lead structures for applications in photodynamic therapy. 5. Synthesis and biological evaluation of water soluble phosphorus(V) 5,10,15,20-tetraalkylporphyrins for PDT

“…Thus, current research targets new photosensitizers with optimized photophysical and pharmacological properties [7]. This often requires significant chemical manipulation [6] (more synthetic steps) or complex formulation strategies [9,10] (liposomes, nanomaterials) whereby the biocompatibility is somewhat unclear. Current bioconjugate research developments [11,12,13,14] (antibodies, sugars, steroids, etc.)…”

Stirring the porphyrin alphabet soup—functionalization reactions for porphyrins

“…In turn, the 610 synthesis of a basic chromophore type must be combined with methods to optimize the delivery and targeting of the active photosensitizer. This can be achieved through nanomedicinal strategies, 68 bioconjugation and dual modality systems.…”