Jump to main content
Jump to site search

Issue 10, 2018
Previous Article Next Article

Characteristics of the excited triplet states of thiolated guanosine derivatives and singlet oxygen generation

Author affiliations

Abstract

Thioguanine is sensitive to UVA light and generates singlet molecular oxygen (1O2*) when exposed to UVA. Three thioguanosine derivatives, 2′,3′,5′-tri-O-acetyl-6-thioguanosine (ta6TGuo), 2′,3′,5′-tri-O-acetyl-8-thioguanosine (ta8TGuo), and 2′,3′,5′-tri-O-acetyl-6,8-dithioguanosine (taDTGuo) were explored photophysically and photochemically. Nanosecond transient absorption and time-resolved near-infrared emission measurements were carried out to investigate the characteristics of their excited triplet states in acetonitrile solution. The quantum yield of intersystem crossing (ΦISC), the intrinsic decay rate constant (k0), the quenching rate constant by 3O2 (kq) and the self-quenching rate constant (kSQ) of their triplet states were all determined. From the precise analysis of the quantum yield of 1O2* generation (ΦΔ) against the concentration of dissolved molecular oxygen, the fraction of the triplet states quenched by dissolved oxygen which gives rise to 1O2* formation (SΔ) was successfully obtained with high accuracy. The ΦΔ values at low oxygen concentrations reveal that these thioguanosines, particularly taDTGuo, can still effectively generate 1O2* at low molecular oxygen concentrations like carcinomatous microenvironments. These findings indicate that taDTGuo would perform well as a potential agent for photo-induced cancer therapies.

Graphical abstract: Characteristics of the excited triplet states of thiolated guanosine derivatives and singlet oxygen generation

Back to tab navigation

Supplementary files

Publication details

The article was received on 09 Jun 2018, accepted on 16 Sep 2018 and first published on 17 Sep 2018


Article type: Paper
DOI: 10.1039/C8PP00240A
Citation: Photochem. Photobiol. Sci., 2018,17, 1469-1476
  •   Request permissions

    Characteristics of the excited triplet states of thiolated guanosine derivatives and singlet oxygen generation

    S. Miyata, S. Tanabe, T. Isozaki, Y. Xu and T. Suzuki, Photochem. Photobiol. Sci., 2018, 17, 1469
    DOI: 10.1039/C8PP00240A

Search articles by author

Spotlight

Advertisements