Photodynamic Therapy (PDT)
with photoactivatable Iridium(III) Complexes
Reactive oxygen species (ROS, 1O2, O2·, OH·, and H2O2) has known as one of the very important factors for biomedical applications, such as phototherapeutics for non-invasive therapy (photodynamic therapy; PDT) and wound healing hemostasis for fast cell recovery from serious injury or surgery. The controlling and understanding of ROS give insight into the clue of cell death mechanism or cell recovery by ROS, which will be helpful to overcome the chronical or pathogenic diseases like cancer or Alzheimer as well as aging. Until now, Ir(III) complexes have known as a potential for PDT application because of their (i) high photostability, (ii) efficient triplet state utilization followed by (iii) high 1O2 quantum yield in aqueous media, and (iv) preference of hypoxia condition.1-2 However, there is no detailed molecular design strategy for ROS generation and cell death mechanism. For this aim, our group have investigated on the Ir(III) complex based photosensitizers or biocompatible polymer for PDT, their drug delivery system (DDS) based on reduction-triggered self-cross-linked polymer nanogel, organelle probes for the understanding of the interaction between proteins during the cell death, and carbohydrate-based polymers for efficient wound healing hemostasis.
In this presentation, Ir(III) complexes based molecular design strategy will be presented for efficient ROS generation and their cell death mechanism. For in vivo application of Ir(III) complexes, systematic improvement based on hyperbranched polyglycerol nanogel is also presented as a DDS. Furthermore, side chain functionalized alginate and chitosan are developed for hemostatic bio-medical application or drug delivery system. Functionalized alginate and chitosan successfully showed hemostasis properties not only in vitro model but also in vivo model.
Keywords: reactive oxygen species, Ir(III) complexes, photodynamic therapy, hemostasis, nanogel
1) J. S. Nam et al. J. Am. Chem. Soc. 138, 10968 (2016)
2) Kang et al. J. Eur. Chem. 23, 1645 (2017)