Freeze-dried heart valve scaffolds.
In this study, structure and biomechanical properties of freeze-dried decellularized porcine pulmonary heart valves were investigated. Heart valves were dissected from porcine hearts. The tissues were decellularized and separated in three groups: (1) without lyoprotectant, (2) with 5% sucrose, and (3) with a mixture of 2.5% sucrose and 2.5% hydroxyl ethylene starch (HES), and then underwent freeze-drying. Freeze-drying in the absence of lyoprotectants caused an overall more disintegrated appearance of the histological architecture of the porcine valves, especially between the fibrosa and the ventricularis layers. Freeze-dried tissues with lyoprotectants have a looser network of collagen and elastic fibers with bigger pore sizes. Tissue freeze-dried in the absence of lyoprotecants had the largest pore sizes, whereas the tissue freeze-dried in the presence of protectants showed pores of intermediate sizes between the decellularized tissue and the unprotected freeze-dried samples. Tissue freeze-dried with sucrose alone displayed less porosity than tissue freeze-dried with the sucrose/HES mixture, whereas no significant differences in biomechanical properties were observed. Decellularization decreased the elastic modulus of artery tissue. The elastic modulus of freeze-dried tissue without protectants resembled that of decellularized tissue. The elastic modulus values of freeze-dried tissue stabilized by lyoprotectants were greater than those of decellularized tissue, but similar to those of native tissue.
Institute of Multiphase Processes, Leibniz Universität Hannover, Hannover, Germany.
Shangping
S
Wang
Tobias
T
Goecke
Carsten
C
Meixner
Axel
A
Haverich
Andres
A
Hilfiker
Willem F
WF
Wolkers
D000818:Animals; D001696:Biomechanical Phenomena; D055119:Elastic Modulus; D005612:Freeze Drying / Q000379:methods*; D006351:Heart Valves / Q000166:cytology* / Q000502:physiology*; D016062:Porosity; D011664:Pulmonary Valve / Q000166:cytology* / Q000502:physiology*; D013552:Swine; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds