Mechanical evaluation of gradient electrospun scaffolds with 3D printed ring reinforcements for tracheal defect repair

Abstract

Tracheal stenosis can become a fatal condition, and current treatments include augmentation of the airway with autologous tissue. A tissue-engineered approach would not require a donor source, while providing an implant that meets both surgeons' and patients' needs. A fibrous, polymeric scaffold organized in gradient bilayers of polycaprolactone (PCL) and poly-lactic-co-glycolic acid (PLGA) with 3D printed structural ring supports, inspired by the native trachea rings, could meet this need. The purpose of the current study was to characterize the tracheal scaffolds with mechanical testing models to determine the design most suitable for maintaining a patent airway. Degradation over 12 weeks revealed that scaffolds with the 3D printed rings had superior properties in tensile and radial compression, with at least a three fold improvement and 8.5-fold improvement, respectively, relative to the other scaffold groups. The ringed scaffolds produced tensile moduli, radial compressive forces, and burst pressures similar to or exceeding physiological forces and native tissue data. Scaffolds with a thicker PCL component had better suture retention and tube flattening recovery properties, with the monolayer of PCL (PCL-only group) exhibiting a 2.3-fold increase in suture retention strength (SRS). Tracheal scaffolds with ring reinforcements have improved mechanical properties, while the fibrous component increased porosity and cell infiltration potential. These scaffolds may be used to treat various trachea defects (patch or circumferential) and have the potential to be employed in other tissue engineering applications.

Nanofibrillar Decellularized Wharton's Jelly Matrix for Segmental Tracheal Repair

“…Next, we investigated how a 2D nanofibrous membrane could be used to construct homogeneous 3D tubular tracheal cartilage with satisfactory mechanical properties in order to apply these findings toward tracheal reconstruction 16. However, a nanofibrous membrane cannot be used alone to construct a tubular structure with sound radial rigidity.…”

“…Furthermore, the construction of a 3D tubular scaffold with controllable lumen diameter and wall thickness from 2D nanofibrous membranes is a technological problem that should be addressed before its further application in trachea tissue engineering 15. At present, limited progress has been achieved in addressing this problem 16. More importantly, no study to date has achieved segmental tracheal defect repair using a 2D DWJM/PCL nanofibrous membrane.…”

3D printing for the design and fabrication of polymer-based gradient scaffolds

“…With this in mind, comparisons using specific gravity tests may not be informative if total porosity is not the varied factor. The existence of such a gradient can be indirectly quantified through functional mechanical testing [75, 78, 80, 81, 83]. To evaluate porosity from sodium chloride leaching, Sherwood et al .…”

Designing a tissue-engineered tracheal scaffold for preclinical evaluation

“…1). Incorporation of additive manufacturing technologies to biosynthetic scaffolds to mimic the cartilaginous rings of the native trachea has been employed in recent TETG designs [18–20], and a primary evaluation metric is a biomimetic mechanical profile. In the current work, we compared the mechanical behavior of our scaffold and ring designs to that of native ovine trachea, to which an optimized TETG scaffold will be applied in future experiments.…”