title: The molecular mechanism of photochemical internalization of cell penetrating peptide-cargo-photosensitizer conjugates.
abstract: In many drug delivery strategies, an inefficient transfer of macromolecules such as proteins and nucleic acids to the cytosol often occurs because of their endosomal entrapment. One of the methods to overcome this problem is photochemical internalization, which is achieved using a photosensitizer and light to facilitate the endosomal escape of the macromolecule. In this study, we examined the molecular mechanism of photochemical internalization of cell penetrating peptide-cargo (macromolecule)-photosensitizer conjugates. We measured the photophysical properties of eight dyes (photosensitizer candidates) and determined the respective endosomal escape efficiencies using these dyes. Correlation plots between these factors indicated that the photogenerated (1)O2 molecules from photosensitizers were highly related to the endosomal escape efficiencies. The contribution of (1)O2 was confirmed using (1)O2 quenchers. In addition, time-lapse fluorescence imaging showed that the photoinduced endosomal escape occurred at a few seconds to a few minutes after irradiation (much longer than (1)O2 lifetime), and that the pH increased in the endosome prior to the endosomal escape of the macromolecule.
authors.affiliation: Department of Medical Bioengineering, Okayama University, 3-1-1 Tsushimanaka, Okayama 700-8530, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohtsuki
authors.affiliation: Department of Medical Bioengineering, Okayama University, 3-1-1 Tsushimanaka, Okayama 700-8530, Japan.
authors.forename: Shunya
authors.initials: S
authors.lastname: Miki
authors.affiliation: Advanced ICT Research Institute Kobe, NICT, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan.
authors.forename: Shouhei
authors.initials: S
authors.lastname: Kobayashi
authors.affiliation: Advanced ICT Research Institute Kobe, NICT, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan.
authors.forename: Tokuko
authors.initials: T
authors.lastname: Haraguchi
authors.affiliation: Institute of Advanced Energy, Kyoto University, Gokasho,Uji, Kyoto 611-0011, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Nakata
authors.affiliation: Department of Applied Chemistry and Biochemical Engineering, Graduate School of Engineering, Shizuoka University, Johoku 3-5-1, Naka-ku, Hamamatsu 432-8561, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Hirakawa
authors.affiliation: Department of Medical Bioengineering, Okayama University, 3-1-1 Tsushimanaka, Okayama 700-8530, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Sumita
authors.affiliation: Department of Medical Bioengineering, Okayama University, 3-1-1 Tsushimanaka, Okayama 700-8530, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Department of Medical Spectroscopy, Hamamatsu University School of Medicine, 1-20-1 Handayayama, Higashi-ku, Hamamatsu, 431-3192, Japan.
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Okazaki
mesh_terms: D000818:Animals; D016466:CHO Cells; D057846:Cell-Penetrating Peptides / Q000008:administration & dosage* / Q000378:metabolism; D003412:Cricetulus; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D016503:Drug Delivery Systems; D011992:Endosomes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D008027:Light; D046911:Macromolecular Substances / Q000378:metabolism; D017319:Photosensitizing Agents / Q000008:administration & dosage* / Q000378:metabolism
chemical_list: D057846:Cell-Penetrating Peptides; D046911:Macromolecular Substances; D017319:Photosensitizing Agents