title: Identification and ultrastructural imaging of photodynamic therapy-induced microfilaments by atomic force microscopy.
abstract: Atomic force microscopy (AFM) is an emerging technique for imaging biological samples at subnanometer resolution; however, the method is not widely used for cell imaging because it is limited to analysis of surface topology. In this study, we demonstrate identification and ultrastructural imaging of microfilaments using new approaches based on AFM. Photodynamic therapy (PDT) with a new chlorin-based photosensitizer DH-II-24 induced cell shrinkage, membrane blebbing, and reorganization of cytoskeletons in bladder cancer J82 cells. We investigated cytoskeletal changes using confocal microscopy and atomic force microscopy. Extracellular filaments formed by PDT were analyzed with a tandem imaging approach based on confocal microscopy and atomic force microscopy. Ultrathin filaments that were not visible by confocal microscopy were identified as microfilaments by on-stage labeling/imaging using atomic force microscopy. Furthermore, ultrastructural imaging revealed that these microfilaments had a stranded helical structure. Thus, these new approaches were useful for ultrastructural imaging of microfilaments at the molecular level, and, moreover, they may help to overcome the current limitations of fluorescence-based microscopy and atomic force microscopy in cell imaging.
authors: Department of Molecular and Cellular Biochemistry and Vascular System Research Center, Kangwon National University School of Medicine, Chuncheon, Kangwon-Do 200-701, Korea.
authors: Se-Hui
authors: SH
authors: Jung
authors: Jin-Young
authors: JY
authors: Park
authors: Je-Ok
authors: JO
authors: Yoo
authors: Incheol
authors: I
authors: Shin
authors: Young-Myeong
authors: YM
authors: Kim
authors: Kwon-Soo
authors: KS
authors: Ha
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects / Q000528:radiation effects / Q000648:ultrastructure*; D000588:Amines / Q000737:chemistry; D001710:Biotin / Q000031:analogs & derivatives / Q000737:chemistry; D045744:Cell Line, Tumor; D006801:Humans; D008027:Light; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D009369:Neoplasms / Q000188:drug therapy / Q000648:ultrastructure*; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011166:Porphyrins / Q000627:therapeutic use
chemical_list: D000588:Amines; C547071:DH-II-24 compound; D017319:Photosensitizing Agents; D011166:Porphyrins; C076022:5-(biotinamido)pentylamine; D001710:Biotin