Non-invasive assessment of elastic modulus of arterial constructs during cell culture using ultrasound elasticity imaging.
Mechanical strength is a key design factor in tissue engineering of arteries. Most existing techniques assess the mechanical property of arterial constructs destructively, leading to sacrifice of a large number of animals. We propose an ultrasound-based non-invasive technique for the assessment of the mechanical strength of engineered arterial constructs. Tubular scaffolds made from a biodegradable elastomer and seeded with vascular fibroblasts and smooth muscle cells were cultured in a pulsatile-flow bioreactor. Scaffold distension was computed from ultrasound radiofrequency signals of the pulsating scaffold via 2-D phase-sensitive speckle tracking. Young's modulus was then calculated by solving the inverse problem from the distension and the recorded pulse pressure. The stiffness thus computed from ultrasound correlated well with direct mechanical testing results. As the scaffolds matured in culture, ultrasound measurements indicated an increase in Young's modulus, and histology confirmed the growth of cells and collagen fibrils in the constructs. The results indicate that ultrasound elastography can be used to assess and monitor non-invasively the mechanical properties of arterial constructs.
Center for Ultrasound Molecular Imaging and Therapeutics, Department of Medicine and Heart and Vascular Institute, University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
Debaditya
D
Dutta
Kee-Won
KW
Lee
Robert A
RA
Allen
Yadong
Y
Wang
John C
JC
Brigham
Kang
K
Kim
D000818:Animals; D001158:Arteries / Q000166:cytology / Q000000981:diagnostic imaging* / Q000254:growth & development*; D002478:Cells, Cultured; D019245:Compressive Strength / Q000502:physiology; D055119:Elastic Modulus / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005347:Fibroblasts / Q000166:cytology / Q000000981:diagnostic imaging* / Q000502:physiology*; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000000981:diagnostic imaging* / Q000502:physiology*; D010215:Papio; D013718:Tensile Strength / Q000502:physiology; D023822:Tissue Engineering / Q000295:instrumentation / Q000379:methods; D054457:Tissue Scaffolds
Arterial construct; Inverse problem; Non-invasive assessment; Tissue engineering; Ultrasound elasticity imaging; Young's modulus