이번주 목요일(6월 5일)에 세미나가 개최됩니다.

많은 참석 부탁드립니다.
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제  목 : Moving Photodynamic Action into the 21st Century

연  사 : prof. Engin Umut Akkaya(Bilkent University)
 

일  시 : 2014년 6월 5일 (목) 오후 4시 30분

장  소 : 화학관 세미나실 (330226호실)

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Moving Photodynamic Action into the 21st Century

Engin U. Akkaya*

eua@fen.bilkent.edu.tr

Department of Chemistry and UNAM-National Nanotechnology Research Center, Bilkent University, 06800 Ankara, Turkey.

Our research group has contributed to the development of molecular logic gates over the years.  However in recent years, the need to move molecular logic from the realm of intellectual exercise to practicality became an urgent matter.  We, among a few others are convinced that the first unequivocal application will present itself in the nanomedicine field.  One particular field of inquiry which could benefit from such fusion of ideas is photodynamic therapy. Photodynamic therapy (PDT) is a noninvasive method of treating malignant tumors and age-related macular degeneration, and is particularly promising in the treatment of multidrug-resistant tumors. The PDT strategy is based on the preferential localization of certain photosensitizers in tumor tissues upon systemic administration. The sensitizer is then excited with red or near infrared (NIR) light, generating singlet oxygen (¹O₂) and thus irreversibly damaging tumor cells. Current practice of PDT is limited to a few functionalized porphyrins and related compounds, however these are not considered to be ideal photosensitizers for use in PDT. Among the limitations, the most prominent is the low extinction coefficient of porphyrins in the body’s therapeutic window (650–800 nm)..  As a consequence, many research groups worldwide are engaged in efforts to develop better sensitizers.  One important aspect is the tight control of the delivery of cytotoxic singlet oxygen to be produced. In an earlier design, we proposed a sensitizer which behaves as an “AND” logic gate.  Later, we proposed a demultiplexer design which can switch from therapeutic to diagnostic mode autonomously.  The other path we are following is trying to find alternative excitation protocols for photodynamic action.  The methodologies which we are currently evaluating are, chemiluminescence, persistent luminescence, and direct production of singlet oxygen.   Our recent progress in these fields of research will be presented. 

References

\'Selective Manipulation of ICT and PET Processes in Styryl-Bodipy Derivatives: Applications in Molecular Logic and Fluorescence Sensing of Metal Ions\' Ö. A. Bozdemir, et al., J. Am. Chem. Soc., 2010,132, 8029-8036.

\'From Virtual to Physical: Integration of Chemical Logic Gates\' R. Guliyev, Ş . Öztürk, Z. Köstereli, E. U. Akkaya, Angew. Chem. Int. Ed., 2011, 50, 9826-9831.

\'Designing Excited States: Theory-Guided Access to Efficient Photosensitizers for Photodynamic Action\' Y. Çakmak, et al., Angew. Chem. Int. Ed., 2011,50, 11937-11941.

\'Cascading of Molecular Logic Gates for Advanced Functions: A Self-Reporting, Activatable Photosensitizer\' Erbas-Cakmak, S.; Akkaya, E. U., Angew. Chem. Int. Ed.2013, 52, 11364.