Electrospun PHEA-PLA/PCL Scaffold for Vascular Regeneration: A Preliminary in Vivo Evaluation

Abstract

Background. There is increasing interest in the development of vessel substitutes, and many studies are currently focusing on the development of biodegradable scaffolds capable of fostering vascular regeneration. We tested a new biocompatible and biodegradable material with mechanical properties similar to those of blood vessels.Methods. The material used comprises a mixture of a,b-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) and polylactic acid (PLA), combined with polycaprolactone (PCL) by means of electrospinning technique. Low-molecular-weight heparin was also linked to the copolymer. A tubular PHEA-PLA/PCL sample was used to create an arteriovenous fistula in a pig model with the use of the external iliac vessels. The flow was assessed by means of Doppler ultrasound examination weekly, and 1 month after the implantation we removed the scaffold for histopathologic evaluation. Results. The implants showed a perfect leak-proof seal and adequate elastic tension to blood pressure. About w3 weeks after the implantation, Doppler examination revealed thrombosis of the graft, so we proceeded to its removal. Histologic examination showed chronic inflammation, with the presence of foreign body cells and marked neovascularization. The material had been largely absorbed, leaving some isolated spot residues. Conclusions. The biocompatibility of PHEA-PLA/PCL and its physical properties make it suitable for the replacement of vessels. In the future, the possibility of functionalizing the material with a variety of molecules, to modulate the inflammatory and coagulative responses, will allow obtaining devices suitable for the replacement of native vessels.

Tubular electrospun scaffolds tested in vivo for tissue engineering

“…During the threading, the polymeric solution is electrospun by coaxial stretch by an electrical potential differential produced by a high voltage source, generally between 5-35Kv, which generates the electric field necessary to overcome the surface tension of the solution and thread the microfilaments towards a collector that can be flat or tubular. 5 This technique allows the production of tridimensional scaffolds made by micro-nanometric polymeric fibers, with similar properties from the ones that confirm the extracellular matrix , permitting cellular growth due to the microporous structure obtained. [6][7] To begin the electrospinning process a biocompatible and biodegradable polymer is needed, such as polycaprolactone (PCL) or polylactic acid (PLA) dissolved in a solvent to produce a viscoelastic solution.…”

Synthesis, Optimal Fabrication, and Physico‐Mechanical Property Evaluation of PCL‐b‐PLLA Diblock Copolymer‐Based Nanoscale Roughness Textured Electrospun Mats

“…Thus, PLA and PCL blended EMs are now being prepared to enhance the mechanical properties and in vivo degradation stability of EMs for various tissue engineering and biomedical applications. [ 38–45 ] The morphology, thermal, microstructural, mechanical, and viscoelastic properties of different PLA/PCL blend‐based EMs have been reported in our previous studies. [ 33,46 ] However, the chemical interaction between the polymer chains in block copolymer of PLA and PCL, reportedly, tends to enhance the miscibility and stability of both the polymers compared to blends.…”

“…[1][2][3][4][5][6][7][8][9][10] The versatility of solution electrospinning lies in its ability to produce electrospun fibers with different orientation and morphology by varying process parameters (applied voltage, receiving distance, collector type, collector speed, orifice diameter tissue engineering and biomedical applications. [38][39][40][41][42][43][44][45] The morphology, thermal, microstructural, mechanical, and viscoelastic properties of different PLA/PCL blend-based EMs have been reported in our previous studies. [33,46] However, the chemical interaction between the polymer chains in block copolymer of PLA and PCL, reportedly, tends to enhance the miscibility and stability of both the polymers compared to blends.…”

Influence of Polyvinyl Alcohol (PVA) on PVA-Poly-N-hydroxyethyl-aspartamide (PVA-PHEA) Microcrystalline Solid Dispersion Films

“…PVA was combined with novel polymer PHEA (25)(26)(27) that has many attractive properties, such as water solubility and absence of toxicity (28). Additionally, it is biodegradable and was used previously in drug delivery systems (29). PHEA is also very hydrophilic and has a high degree of mucoadhesion when formulated at 2.5% w/v in combination with PVA at 5% w/v (30).…”