Development and assessment of a biodegradable solvent cast polyester fabric small‐diameter vascular graft

Abstract

Adjusting the mechanical properties of polyester-based vascular grafts is crucial to achieving long-term success in vivo. While previous studies using a fabric-based approach have achieved some success, a central issue with pure poly(lactic acid) (PLA) or poly(glycolic acid) (PGA) grafts sealed with poly(DL-caprolactone-co-lactic acid) (P(CL/LA)) has been stenosis. Intimal hyperplasia, a leading cause of stenosis, can be caused by the mechanical incompatibility of synthetic vascular grafts. Investigating the performance of poly(glycolic-co-lactic acid) grafts (PGLA) could lead to insight into whether graft stenosis stems from mechanical issues such as non-compliance and unfavorable degradation times. This could be achieved by examining grafts with tunable mechanical properties between the ranges of such properties in pure PGA and PLA based grafts. In this study, we examined PGLA-based grafts sealed with different P(CL/LA) solutions to determine the PGLA-P(CL/LA) grafts' mechanical properties and tissue functionality. Cell attachment and proliferation on graft surfaces were also observed. For in vivo assessment, grafts were implanted in a mouse model. Mechanical properties and degradation times appeared adequate compared to recorded values of vessels used in autograft procedures. Initial neotissue formation was observed in the grafts and patency maintained during the pilot study. This study presents a ~1mm diameter degradable graft demonstrating suitable mechanical properties and in vivo pilot study success, enabling further investigation into the tuning of mechanical properties to reduce complications in degradable polyester fabric-based vascular grafts.

Preclinical study of patient-specific cell-free nanofiber tissue-engineered vascular grafts using 3-dimensional printing in a sheep model

“…Previous studies also have examined TEVG fabrication using solvent-cast molding processes with synthetic biodegradable polymers, but 3D-printing TEVG scaffolds would best streamline the process of creating a patient-specific conduit. 20,21 …”

In Vitro Endothelialization of Biodegradable Vascular Grafts Via Endothelial Progenitor Cell Seeding and Maturation in a Tubular Perfusion System Bioreactor

“…Similar attachment rates have been observed on these materials in other studies. 27,32 The physical method of seeding may be altered to enhance cell retention on grafts. Alternatively, techniques to improve cell adhesion to biomaterials have been employed to improve EPC attachment to vascular graft materials.…”

“…27,32 Rectangular sections of 6.00 · 4.00 mm were cut from a PGA polymer BIOFELT (Biomedical Structures). These sections were then inserted into a polypropylene tube with an inner lumen diameter of 1.4 mm.…”

“…For the scaffold portion of this work, we used a solvent-cast, poly(glycolic acid) (PGA)-based felt graft with a poly(DLcaprolactone-co-lactic acid) (PCLLA) solution characterized in a previous study. 27 The graft is mechanically compatible with vascular tissues, porous, biodegradable, and demonstrated good cell adhesion and infiltration when implanted in a mouse model. This scaffold platform was chosen for its ease of production and modification.…”

Fabrication Techniques for Vascular and Vascularized Tissue Engineering

“…For example, a knitted macroporous mesh produced by melt‐spun poly( l,d ‐lactic acid) (P(L/D)LA) fibers was used to increase the burst pressure of a fibrin‐based MVG78b and a Dacron mesh was placed between a SMC‐encapsulated collagen inner layer and a FB‐encapsulated collagen outer layer in a molded MVG to prevent delamination or tearing 75a. Similarly, PGA, PLLA and PLGA nonwoven meshes have been used as the framework for MVGs made fabricated with a copolymer of lactic acid and ε‐caprolactone to generate porous grafts with enhanced mechanical properties …”