Flexure Based Device for Cyclic Strain Mediated Osteogenic Differentiation

Abstract

Application of lowmagnitude strains to cells on smallthickness scaffolds, such as those for rodent calvarial defect models, is problematic, because general translation systems have limitations in terms of generating lowmagnitude smooth signals. To overcome this limitation, we developed a cyclic strain generator using a customized, flexurebased, translational nanoactuator that enabled generation of lowmagnitude smooth strains at the subnanoto micrometer scale to cells on smallthickness scaffolds. The cyclic strain generator we developed showed predictable operational characteristics by generating a sinusoidal signal of a few micrometers (4.5 خ¼m) without any distortion. Threedimensional scaffolds fitting the criticalsize rat calvarial defect model were fabricated using poly(caprolactone), poly(lacticcoglycolic acid), and tricalcium phosphate. Stimulation of human adipose–derived stem cells (ASCs) on these fabricated scaffolds using the cyclic strain generator we developed resulted in upregulated osteogenic marker expression compared to the nonstimulated group. These preliminary in vitro results suggest that the cyclic strain generator successfully provided mechanical stimulation to cells on smallthickness scaffolds, which influenced the osteogenic differentiation of ASCs.