The effect of ultrasound stimulation versus bioreactors on neocartilage formation in tissue engineering scaffolds seeded with human chondrocytes in vitro

Abstract Pulsed ultrasound (1 MHz, 67 mW/cm 2 Ispta, and 10 min/day) promoted cell proliferation and matrix deposition in low-density 2D (∼6 × 10 3  cells/cm 2 ) as well as 3D (∼4 × 10 6  cells/cm 3 ) chondrocyte cultures. The beneficial effect of ultrasound on neocartilage formation only last 28 days, shorter than that of bioreactors.