Search for Electrospun Nanofiber Materials Matching The Mechanical Properties of Native Aortic Valve

Abstract—Porous electrospun nanofiber materials are very promising as matrixes for heart valve tissue engineering. The perfect material for this purpose has to be both mechanically strong and deformable at the same time. Materials from gelatin, polyurethane (PUR), polylactic acid (PLA) and polycaprolactone (PCL) made in several density variants were analyzed using uniaxial tensile tests and compared to mechanical properties of porcine aortic valve (AV) leaflets in radial and circumferential directions. In circumferential direction modulus of elasticity (E) of AV is 9.7±1.3MPa and - 1.0±0.2MPa in radial. Ultimate strain and stress is 44.8±5.9% and 2.3±0.6MPa in circumferential and 95.6±31.4% and 0.5±0.2MPa in radial direction for AV. Closest of the materials to native AV in circumferential direction was PUR with area density 6.2 g/m2 showing E of 3.9±0.5 MPa, ultimate stress and strain - 5.3±1.68MPa and 141.8±43.9% respectively. Closest to radial direction was gelatin with area density 5.7 g/m2 showing E of 0.64±0.14 MPa, ultimate stress and strain - 0.38±0.05MPa and 82.53±10.20% respectively. Native AV leaflets have a non-linear and anisotropic response to stress in uniaxial tensile tests. To model their mechanical properties we suggest using a combined material made of gelatin and PUR with their fibbers predominantly orientated in perpendicular directions.

Index Terms—Heart valve, mechanical properties, nanofiber materials, tissue engineering.

M. K. and P. S. were with Augusts Kirhensteins Institute of Microbiology and Virology, Ratsupites str. 5, Riga, Latvia and still are with Department of Cardiac Surgery, Pauls Stradins Clinical University Hospital, Pilsonu str. 13, Riga, Latvia (e-mail: martins.kalejs@stradini.lv, peteris.stradins@stradini.lv).
R. L. is with Department of Cardiac Surgery, Pauls Stradins Clinical University Hospital, Pilsonu str. 13, Riga, Latvia (e-mail: valentina@stradini.lv).
I. O. and V. K. are with Laboratory of biomechanics, Riga Stradins university, Dzirciema str. 16, Riga, Latvia (e-mail: iveta.ozolanta@RSU.lv, V. K. e-mail: Kasyanov@latnet.lv).
M. M. is with Augusts Kirhensteins Institute of Microbiology and Virology, Ratsupites str. 5, Riga, Latvia (e-mail: modra.murovska@rsu.lv).