Photodynamic therapy (PDT) and photodynamic antimicrobial chemotherapy (PACT) are treatment modalities that are based on the ability of photoactive compounds or photosensitizers (PS) which under illumination with visible light produce reactive oxygen species (ROS) leading to cell death. PDT is used clinically for various neoplastic and non-neoplastic conditions using licensed PSs. In photodynamic antimicrobial chemotherapy, ROS allow non-specific attack at the microbial level producing a broad spectrum antibacterial activity regardless of the conventional drug-resistance status as well as antifungal and antiviral activity. Moreover, ROS are active against the biofilm structure itself causing general oxidative breakdown alongside microbial killing. PACT is proposed as a potential, low-cost approach to the treatment of locally occurring infection.

Limitations of both anti-cancer PDT and antimicrobial PACT include mainly poor solubility and permeability of PSs, non selective accumulation at the target site and sub-optimal selectivity, which present a formulation challenge.  Such limitations could be overcome by drug delivery strategies, particularly at the nano-scale.

Scope of the project: To apply a nanotechnological approach to the enhancement of PDT and PACT. This is of great scientific and practical importance in view of the advantage of PDT as more effective and less destructive anti-cancer therapy compared to surgery, chemotherapy and radiotherapy, particularly in immunocompromised patients and the cost/effectiveness of local infections, even those caused by resistant microbial strains.

Objective: To develop nano-scale carriers for the controlled delivery of photosensitizers and/or anti-cancer or antimicrobial chemotherapeutic agents in order to enhance the effectiveness of PDT and PACT. 

Materials:  

Polymers with different physico-chemical properties will be used for the development of drug-loaded nanocarriers and nanofibres for PDT and PACT respectively. These will be assessed both in vitro and in vivo.

Expected outcomes: Application of nanotechnology to the enhancement of cost effective alternative treatment modalities to improve the potential therapeutic outcomes and quality of life of a large number of patients