Synthesis and characterization of polycaprolactone urethane hollow fiber membranes as small diameter vascular grafts

Abstract

The design of bioresorbable synthetic small diameter (<6mm) vascular grafts (SDVGs) capable of sustaining long-term patency and endothelialization is a daunting challenge in vascular tissue engineering. Here, we synthesized a family of biocompatible and biodegradable polycaprolactone (PCL) urethane macromers to fabricate hollow fiber membranes (HFMs) as SDVG candidates, and characterized their mechanical properties, degradability, hemocompatibility, and endothelial development. The HFMs had smooth surfaces and porous internal structures. Their tensile stiffness ranged from 0.09 to 0.11N/mm and their maximum tensile force from 0.86 to 1.03N, with minimum failure strains of approximately 130%. Permeability varied from 1 to 14×10(-6)cm/s, burst pressures from 1158 to 1468mmHg, and compliance from 0.52 to 1.48%/100mmHg. The suture retention forces ranged from 0.55 to 0.81N. HFMs had slow degradation profiles, with 15 to 30% degradation after 8weeks. Human endothelial cells proliferated well on the HFMs, creating stable cell layer coverage. Hemocompatibility studies demonstrated low hemolysis (<2%), platelet activation, and protein adsorption. There were no significant differences in the hemocompatibility of HFMs in the absence and presence of endothelial layers. These encouraging results suggest great promise of our newly developed materials and biodegradable elastomeric HFMs as SDVG candidates.

Preclinical induced membrane model to evaluate synthetic implants for healing critical bone defects without autograft

“…Moreover, the ideal tissue engineered solution for critical bone loss would be employed as a single‐step procedure. With this goal, we designed a 3D printed biodegradable composite PCL/β‐TCP osteoconductive scaffold to substitute as bone graft and a synthetic PCL‐based microporous polymer film to create an artificial induced membrane inspired by the traditional Masquelet technique . The purpose of this study was: (i) to establish a novel two‐stage induced membrane rodent model utilizing a synthetic implant to replace autologous bone graft; and (ii) to introduce a single‐stage modification intended to evaluate engineered membranes in this small animal model for single step bone healing.…”

Tunable Elastomers with an Antithrombotic Component for Cardiovascular Applications

“…These results suggest that the inclusion of dipyridamole decreases the activation of platelets on the polyurethane surfaces, supporting the suitability of our polyurethane substrates for blood‐contacting interfaces in implants and devices. In our previous studies, we have characterized the in vitro platelet adhesion, protein adsorption, and hemolytic potential of related polycaprolactone‐based polyurethanes and observed statistically equivalent or improved behavior compared to commercially available vessel graft materials . We anticipate that our new family of dipyridamole‐containing elastomers has the potential for even greater hemocompatibility due to the tethering and slow release of the antiplatelet component.…”

“…Previously, we have reported the use of biodegradable polyurethanes for application in cardiovascular tissue engineering . Here we report the development of a novel family of biodegradable polyurethanes with improved mechanical strength, elasticity, biocompatibility, and thromboresistance by incorporation of an antiplatelet agent.…”

State of the Art of Small‐Diameter Vessel‐Polyurethane Substitutes

“…In addition, the steric effect is also an important factor. For example, when small molecular polyol is used as the extender, the one with side groups has a faster degradation rate than that without side groups because the side chains can disrupt the packing of polyol chains as soft segment …”

“…As the studies progressed, it was found that the general properties of PCL‐based PESU were relatively achievable referring to the vascular scaffolds except for biodegradability, which was, therefore, the topic of the following researches, although the degradation rate was still not matched with the growth of new vascular tissue for a period of time . Some researchers believed that the PCL‐based PESU scaffolds degraded too fast in the body (30% of weight loss after 8 weeks), so a family of biodegradable PESU elastomers in which PCL was partially substituted by polycarbonate diol (PCDL) with different ratios was synthesized and characterized, and only 1% of degradation after 8 weeks was obtained . In addition to polyols, the chain extender is also a main aspect for adjusting the degradation rate of PESU.…”