title: Photosensitiser delivery for photodynamic therapy. Part 2: systemic carrier platforms.
abstract: BACKGROUND
  The treatment of solid tumours and angiogenic ocular diseases by photodynamic therapy (PDT) requires the injection of a photosensitiser (PS) to destroy target cells through a combination of visible light irradiation and molecular oxygen. There is currently great interest in the development of efficient and specific carrier delivery platforms for systemic PDT.
  
  
  OBJECTIVE
  This article aims to review recent developments in systemic carrier delivery platforms for PDT, with an emphasis on target specificity.
  
  
  METHODS
  Recent publications, spanning the last five years, concerning delivery carrier platforms for systemic PDT were reviewed, including PS conjugates, dendrimers, micelles, liposomes and nanoparticles.
  
  
  CONCLUSIONS
  PS conjugates and supramolecular delivery platforms can improve PDT selectivity by exploiting cellular and physiological specificities of the targeted tissue. Overexpression of receptors in cancer and angiogenic endothelial cells allows their targeting by affinity-based moieties for the selective uptake of PS conjugates and encapsulating delivery carriers, while the abnormal tumour neovascularisation induces a specific accumulation of heavy weighted PS carriers by enhanced permeability and retention (EPR) effect. In addition, polymeric prodrug delivery platforms triggered by the acidic nature of the tumour environment or the expression of proteases can be designed. Promising results obtained with recent systemic carrier platforms will, in due course, be translated into the clinic for highly efficient and selective PDT protocols.
authors.affiliation: Queens University Belfast, Medical Biology Centre, School of Pharmacy, 97 Lisburn Road, Belfast BT9 7BL, UK.
authors.forename: Stéphane A
authors.initials: SA
authors.lastname: Sibani
authors.forename: Paul A
authors.initials: PA
authors.lastname: McCarron
authors.forename: A David
authors.initials: AD
authors.lastname: Woolfson
authors.forename: Ryan F
authors.initials: RF
authors.lastname: Donnelly
mesh_terms: D000818:Animals; D050091:Dendrimers; D004337:Drug Carriers; D016503:Drug Delivery Systems; D006801:Humans; D008081:Liposomes; D008823:Micelles; D053758:Nanoparticles; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D050091:Dendrimers; D004337:Drug Carriers; D008081:Liposomes; D008823:Micelles; D017319:Photosensitizing Agents