title: In Vivo Biophysical-stimulation Platform Applied to Rodent Calvarial Bone-defect Models.
abstract: Biophysical strain has been applied widely for bone regeneration. However, application of low-magnitude strains to cells on small-thickness scaffolds is problematic, especially in rodent calvarial defect models, because general translation systems have limitations in terms of generating low-magnitude smooth signals. To overcome these limitations, we developed an in vitro biophysical-stimulation platform for stimulation of cells on small-thickness scaffolds for rodent calvarial bone defects. The customized flexure-based translational nanoactuator enables generation of low-magnitude smooth signals at the subnano- to micrometer-scale. This nanoactuator, which is equipped with a piezoelectric actuator, is suitable for biological applications because it can generate friction-free motion with a high resolution. Moreover, its operation without wear or deterioration eliminates contamination factors in cell culture environments. The developed in vitro biophysical-stimulation platform using these nanoactuators showed predictable operational characteristics. Also, a few-micrometer sinusoidal signal was generated successfully without any distortion. Three-dimensional scaffolds fitting the critical-size rat calvarial defect model were fabricated using poly(caprolactone), poly(lactic-co-glycolic acid), and tricalcium phosphate. Runt-related transcription factor 2 expression was increased upon stimulation of human adipose-derived stem cells (ASCs) on these scaffolds were stimulated in the in vitro biophysical-stimulation platform. Additionally, the use of this platform resulted in up-regulation of alkaline phosphate, osteopontin, and osterix expression compared to the non-stimulated group. These preliminary in vitro results suggest that the biophysical environment provided by the in vitro biophysical-stimulation platform influences the osteogenic differentiation of ASCs.
authors.forename: Dong-Woo
authors.initials: DW
authors.lastname: Cho
authors.forename: Kyung Shin
authors.initials: KS
authors.lastname: Kang
authors.forename: Young Hun
authors.initials: YH
authors.lastname: Jeong
authors.forename: Jung Min
authors.initials: JM
authors.lastname: Hong
authors.forename: Woon-Jae
authors.initials: WJ
authors.lastname: Yong
authors.forename: Jong-Won
authors.initials: JW
authors.lastname: Rhie