Elastase-sensitive elastomeric scaffolds with variable anisotropy for soft tissue engineering.
OBJECTIVE
To develop elastase-sensitive polyurethane scaffolds that would be applicable to the engineering of mechanically active soft tissues.


METHODS
A polyurethane containing an elastase-sensitive peptide sequence was processed into scaffolds by thermally induced phase separation. Processing conditions were manipulated to alter scaffold properties and anisotropy. The scaffold's mechanical properties, degradation, and cytocompatibility using muscle-derived stem cells were characterized. Scaffold in vivo degradation was evaluated by subcutaneous implantation.


RESULTS
When heat transfer was multidirectional, scaffolds had randomly oriented pores. Imposition of a heat transfer gradient resulted in oriented pores. Both scaffolds were flexible and relatively strong with mechanical properties dependent upon fabrication conditions such as solvent type, polymer concentration and quenching temperature. Oriented scaffolds exhibited anisotropic mechanical properties with greater tensile strength in the orientation direction. These scaffolds also supported muscle-derived stem cell growth more effectively than random scaffolds. The scaffolds expressed over 40% weight loss after 56 days in elastase containing buffer. Elastase-sensitive scaffolds were complete degraded after 8 weeks subcutaneous implantation in rats, markedly faster than similar polyurethanes that did not contain the peptide sequence.


CONCLUSIONS
The elastase-sensitive polyurethane scaffolds showed promise for application in soft tissue engineering where controlling scaffold mechanical properties and pore architecture are desirable.
McGowan Institute for Regenerative Medicine, 100 Technology Drive, Pittsburgh, Pennsylvania 15219, USA.
Jianjun
J
Guan
Kazuro L
KL
Fujimoto
William R
WR
Wagner
D020341:Absorbable Implants; D000818:Animals; D016880:Anisotropy; D049109:Cell Proliferation; D002478:Cells, Cultured; D020724:Elastomers / Q000008:administration & dosage / Q000138:chemical synthesis / Q000378:metabolism*; D005260:Female; D006868:Hydrolysis; D007279:Injections, Subcutaneous; D051379:Mice; D032342:Muscle Cells / Q000378:metabolism; D010196:Pancreatic Elastase / Q000378:metabolism*; D018583:Pliability; D011140:Polyurethanes / Q000008:administration & dosage / Q000138:chemical synthesis / Q000378:metabolism*; D016062:Porosity; D051381:Rats; D011917:Rats, Inbred Lew; D013234:Stem Cells / Q000378:metabolism; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D023822:Tissue Engineering; D054457:Tissue Scaffolds
D020724:Elastomers; D011140:Polyurethanes; D010196:Pancreatic Elastase