Fabrication of elastomeric scaffolds with curvilinear fibrous structures for heart valve leaflet engineering

Abstract

Native semi-lunar heart valves are composed of a dense fibrous network that generally follows a curvilinear path along the width of the leaflet. Recent models of engineered valve leaflets have predicted that such curvilinear fiber orientations would homogenize the strain field and reduce stress concentrations at the commissure. In the present work, a method was developed to reproduce this curvilinear fiber alignment in electrospun scaffolds by varying the geometry of the collecting mandrel. Elastomeric poly(ester urethane)urea was electrospun onto rotating conical mandrels of varying angles to produce fibrous scaffolds where the angle of fiber alignment varied linearly over scaffold length. By matching the radius of the conical mandrel to the radius of curvature for the native pulmonary valve, the electrospun constructs exhibited a curvilinear fiber structure similar to the native leaflet. Moreover, the constructs had local mechanical properties comparable to conventional scaffolds and native heart valves. In agreement with prior modeling results, it was found under quasi-static loading that curvilinear fiber microstructures reduced strain concentrations compared to scaffolds generated on a conventional cylindrical mandrels. Thus, this simple technique offers an attractive means for fabricating scaffolds where key microstructural features of the native leaflet are imitated for heart valve tissue engineering.

Mechanical and microstructural analysis of a radially expandable vascular conduit for neonatal and pediatric cardiovascular surgery

“…Each year, over 35,000 children are born in America with congenital heart defects. 1,2 In pediatric cardiovascular surgery, no currently available vascular conduit provides the potential for growth. As newborns triple their birth weight in the first year, infants outgrow devices quickly.…”

Effect of Fluid Viscosity on Noise of Bileaflet Prosthetic Heart Valve

“…In the United States, over 80,000 heart valve transplant operations are performed annually and over 300,000 heart surgery operations worldwide [1,2]. Many of the mechanisms that form the basis of the pathophysiology and progress of heart disease have not yet been fully explored, creating difficulties in the medical therapy development [3,4]. In connection with this, the most effective treatment for the pathology of the affected valves is surgical intervention.…”

JetValve: Rapid manufacturing of biohybrid scaffolds for biomimetic heart valve replacement

“…The mechanical properties of the valvular leaflets determines the stress and strain fields within the tissue during the cardiac cycle, ultimately enabling their functionality [34, 36]. Accordingly, elastic, fibrous scaffolds such as JetValves should be designed to mimic these mechanical properties to ensure optimal functionality in flow [37]. We therefore designed the stretch-dependent, biaxial stiffness of our scaffolds to recapitulate that of the native leaflet ECM.…”