Acta Chim. Sinica ›› 2015, Vol. 73 ›› Issue (7): 723-728.DOI: 10.6023/A15030197 Previous Articles     Next Articles



龙飒然, 宛岩, 夏安东   

  1. 中国科学院化学研究所 光化学重点实验室 北京 100190
  • 投稿日期:2015-03-22 发布日期:2015-05-13
  • 通讯作者: 夏安东
  • 基金资助:

    项目受国家自然科学基金(Nos. 21333012, 21373232)及中国科学院先导专项(No. XDB12020200)资助.

Spectral Properties of Water-Soluble Conjugated Polymer PFP/DNA/Porphyrin Complex

Long Saran, Wan Yan, Xia Andong   

  1. Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190
  • Received:2015-03-22 Published:2015-05-13
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21333012, 21373232) and the Chinese Academy of Sciences (No. XDB12020200).

Photodynamic therapy (PDT) is a particular treatment of tumors, which localizes the biological responses by the way that light is applied. In this paper, we have designed a water-soluble system potentially for PDT, which could selectively generate singlet oxygen efficiently under both of one- and two-photon excitation. This complex consists of a cationic water-soluble conjugated polymer PFP, anionic DNA and a cationic porphyrin. The cationic conjugated polymer PFP and porphyrin are connected by anionic DNA through electrostatic interactions. Energy transfer from conjugated polymer PFP (donor) to porphyrin (acceptor) is available since the considerable overlapping between the emission of donor and the absorption of acceptor (S0→S2). Steady-state spectra and fluorescence lifetime measurements have been performed on the complex with different DNA sequences in order to achieve the energy transfer efficiency. The results of steady-state fluorescence spectra show that there is a remarkable change of fluorescence intensity of the complex with G-quadruplex DNA, which indicates significant energy transfer from the donor to the acceptor. Furthermore, the greatest change of fluorescence lifetime measured by means of time-correlated single photon counting (TCSPC) also proves the highest energy transfer efficiency of the system with G-quadruplex DNA. Singlet oxygen quantum yield can be obtained by the detection of singlet oxygen emission spectra. Porphyrin bound to G-quadruplex DNA has the highest singlet oxygen quantum yield, which suggests this system a possible application in PDT since singlet oxygen could kill tumor cells. Two-photon absorption cross section has also been measured, which reflects the light-harvesting efficiency of the conjugated polymer PFP. The result shows that the conjugated polymer PFP owns large two-photon absorption cross section in the region of 720~850 nm where the transmission in tissue is higher compared to the visible light. The energy transfer efficiency and singlet oxygen quantum yield are both selective for different DNA sequences. G-quadruplex DNA that is very rich in tumor cells has the highest selectivity, which makes this system a potential application in PDT.

Key words: G-Quadruplex DNA, porphyrin, two-photon absorption, singlet oxygen, energy transfer