title: Influence of cell printing on biological characters of chondrocytes.
abstract: OBJECTIVE
  To establish a two-dimensional biological printing technique of chondrocytes and compare the difference of related biological characters between printed chondrocytes and unprinted cells so as to control the cell transfer process and keep cell viability after printing.
  
  
  METHODS
  Primary chondrocytes were obtained from human mature and fetal cartilage tissues and then were regularly sub-cultured to harvest cells at passage 2 (P2), which were adjusted to the single cell suspension at a density of 1×10(6)/mL. The experiment was divided into 2 groups: experimental group P2 chondrocytes were transferred by rapid prototype biological printer (driving voltage value 50 V, interval in x-axis 300 μm, interval in y-axis 1500 μm). Afterwards Live/Dead viability Kit and flow cytometry were respectively adopted to detect cell viability; CCK-8 Kit was adopted to detect cell proliferation viability; immunocytochemistry, immunofluorescence and RT-PCR was employed to identify related markers of chondrocytes; control group steps were the same as the printing group except that cell suspension received no printing.
  
  
  RESULTS
  Fluorescence microscopy and flow cytometry analyses showed that there was no significant difference between experimental group and control group in terms of cell viability. After 7-day in vitro culture, control group exhibited higher O.D values than experimental group from 2nd day to 7th day but there was no distinct difference between these two groups (P>0.05). Inverted microscope observation demonstrated that the morphology of these two groups had no significant difference either. Similarly, Immunocytochemistry, immunofluorescence and RT-PCR assays also showed that there was no significant difference in the protein and gene expression of type II collagen and aggrecan between these two groups (P>0.05). Conclusion Cell printing has no distinctly negative effect on cell vitality, proliferation and phenotype of chondrocytes. Biological printing technique may provide a novel approach for realizing the oriented, quantificational and regular distribution of chondrocytes in a two-dimensional plane and lay the foundation for the construction of three-dimensional cell printing or even organ printing system.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai Tissue Engineering Key Laboratory, Shanghai Research Institute of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Rapid Prototyping Center of Shanghai University China.
authors.forename: Miao
authors.initials: M
authors.lastname: Qu
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai Tissue Engineering Key Laboratory, Shanghai Research Institute of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Rapid Prototyping Center of Shanghai University China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Gao
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai Tissue Engineering Key Laboratory, Shanghai Research Institute of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Rapid Prototyping Center of Shanghai University China.
authors.forename: Yikang
authors.initials: Y
authors.lastname: Hou
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai Tissue Engineering Key Laboratory, Shanghai Research Institute of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Rapid Prototyping Center of Shanghai University China.
authors.forename: Congcong
authors.initials: C
authors.lastname: Shen
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai Tissue Engineering Key Laboratory, Shanghai Research Institute of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Rapid Prototyping Center of Shanghai University China.
authors.forename: Yourong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai Tissue Engineering Key Laboratory, Shanghai Research Institute of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Rapid Prototyping Center of Shanghai University China.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhu
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai Tissue Engineering Key Laboratory, Shanghai Research Institute of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Rapid Prototyping Center of Shanghai University China.
authors.forename: Hengjian
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai Tissue Engineering Key Laboratory, Shanghai Research Institute of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Rapid Prototyping Center of Shanghai University China.
authors.forename: Haisong
authors.initials: H
authors.lastname: Xu
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai Tissue Engineering Key Laboratory, Shanghai Research Institute of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Rapid Prototyping Center of Shanghai University China.
authors.forename: Gang
authors.initials: G
authors.lastname: Chai
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai Tissue Engineering Key Laboratory, Shanghai Research Institute of Plastic and Reconstructive Surgery, Shanghai 9th People's Hospital, Rapid Prototyping Center of Shanghai University China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
keywords: Chondrocytes; cell printing; proliferation; tissue engineering; viability