title: Multiphoton imaging of myogenic differentiation in gelatin-based hydrogels as tissue engineering scaffolds.
abstract: BACKGROUND
  Hydrogels can serve as three-dimensional (3D) scaffolds for cell culture and be readily injected into the body. Recent advances in the image technology for 3D scaffolds like hydrogels have attracted considerable attention to overcome the drawbacks of ordinary imaging technologies such as optical and fluorescence microscopy. Multiphoton microscopy (MPM) is an effective method based on the excitation of two-photons. In the present study, C2C12 myoblasts differentiated in 3D gelatin hydroxyphenylpropionic acid (GHPA) hydrogels were imaged by using a custom-built multiphoton excitation fluorescence microscopy to compare the difference in the imaging capacity between conventional microscopy and MPM.
  
  
  RESULTS
  The physicochemical properties of GHPA hydrogels were characterized by using scanning electron microscopy and Fourier-transform infrared spectroscopy. In addition, the cell viability and proliferation of C2C12 myoblasts cultured in the GHPA hydrogels were analyzed by using Live/Dead Cell and CCK-8 assays, respectively. It was found that C2C12 cells were well grown and normally proliferated in the hydrogels. Furthermore, the hydrogels were shown to be suitable to facilitate the myogenic differentiation of C2C12 cells incubated in differentiation media, which had been corroborated by MPM. It was very hard to get clear images from a fluorescence microscope.
  
  
  CONCLUSIONS
  Our findings suggest that the gelatin-based hydrogels can be beneficially utilized as 3D scaffolds for skeletal muscle engineering and that MPM can be effectively applied to imaging technology for tissue regeneration.
authors.affiliation: Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan, 46241 Korea.
authors.forename: Min Jeong
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan, 46241 Korea.
authors.forename: Yong Cheol
authors.initials: YC
authors.lastname: Shin
authors.affiliation: Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan, 46241 Korea.
authors.forename: Jong Ho
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan, 46241 Korea.
authors.forename: Seung Won
authors.initials: SW
authors.lastname: Jun
authors.affiliation: Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan, 46241 Korea.
authors.forename: Chang-Seok
authors.initials: CS
authors.lastname: Kim
authors.affiliation: Department of Molecular Science and Technology, Ajou University, Suwon, 16499 Korea.
authors.forename: Yunki
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Medical Engineering, Cellbiocontrol Laboratory, Yonsei University College of Medicine, Seoul, 03722 Korea.
authors.forename: Jong-Chul
authors.initials: JC
authors.lastname: Park
authors.affiliation: Department of Biomedical Science, CHA University, Gyeonggi-do, 11160 Korea.
authors.forename: Soo-Hong
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Molecular Science and Technology, Ajou University, Suwon, 16499 Korea.
authors.forename: Ki Dong
authors.initials: KD
authors.lastname: Park
authors.affiliation: Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan, 46241 Korea.
authors.forename: Dong-Wook
authors.identifier: 0000-0001-8314-1981
authors.initials: DW
authors.lastname: Han
keywords: 3D scaffolds; C2C12 myoblast; Hydrogel; Multiphoton microscopy; Myogenic differentiation