Electrospun polyphosphazene nanofibers for in vitro rat endothelial cells proliferation

Abstract

A large variety of natural and synthetic polymers have been explored as scaffolds for the seeding and growth of different types of cells. To fabricate a scaffold that can be used as a synthetic extracellular matrix (ECM), it is important to replicate the nanoscale dimensions of natural ECM. The electrospinning process allows to produce ultrathin fibers so that this method represents a suitable approach to scaffold fabrication for tissue engineering applications. In this work, the feasibility of obtaining flat or tubular matrices from biocompatible poly[(ethyl phenylalanato)(1.4) (ethyl glycinato)(0.6) phosphazene] by electrospinning was evaluated and the effect of process parameters on the diameter of nanofibers was examined. The adhesion and growth of rat neuromicrovascular endothelial cells cultured on sheets and tubes composed by the polymer with an average fiber diameter of 850 +/- 150 nm were also reported. Microscopic examination of the seeded tubes demonstrated that, after 16 days of incubation, endothelial cells formed a monolayer on the whole surface. These results are the first step to demonstrate that tubes of biodegradable polyphosphazenes might be a feasible model to construct human tissues such as vessels or cardiac valves.

Effect of solvent on surface wettability of electrospun polyphosphazene nanofibers

“…Therefore, polyorganophazenes could be proper polymers to investigate the effect of different solvents on the surface properties of electrospun nanofibers, but reports on electrospun biodegradable polyphosphazene nanofibers were limited. 22,23 In this article, poly[(alanino ethyl ester) 0.67 (glycino ethyl ester) 0.33 phosphazene] (PAGP) and poly(e-caprolactone) (PCL) were synthesized and electrospun by using trifluoroethanol (TFE), chloroform (TCM), dichloromethane (DCM), or tetrahydrofuran (THF) as a solvent. In comparison, PAGP and PCL solventcasting films were also prepared from the four solvents.…”

Electrospun Polyphosphazene Nanofibers for In Vitro Osteoblast Culture

“…Preparation and characterization of PPhe-GlyP has recently been described with the following procedure variations (Carampin et al, 2007). Briefly, the poly(dichlorophospazene) was obtained from thermal ring-opening polymerization of hexachlorocyclotriphosphazene.…”

“…The thickness of the scaffolds was measured by a micrometer knowing the bulk density of PPhe-GlyP (Carampin et al, 2007), PLA, and PLC: The porosity of the scaffolds was calculated using the corresponding apparent densities according to Ma et al [25].…”

“…The mass loss of the dried sample can be ascribed to the two previous degradation processes and to hydrolysis of the skeleton of the polyphosphazene chain by the deprotected carboxylic acid function of the substituent units or attack by H + ions on skeletal nitrogen atoms according to the mechanism of hydrolytic breakdown for amino acid ester polyphosphazene (Allcock and Kwon, 1988). This degradation reaction of phosphorus-nitrogen chains is slower that the two previous mechanisms and is the most important process for the weight loss of the polymer because it leads to a molecular-weight decrease (Carampin et al, 2007;Ruiz et al, 1993. ) It is interesting to observe that the disk retains its dimensions and that the weight of the wet film is always higher than the initial weight: The water uptake due to the increase in polymer hydrophilicity hides the weight loss during the 100-day test period.…”

“…Alanine ethyl ester-substituted polyphosphazene membranes was used as a temporary barrier with release of trimethoprin or succinylsulfathiazole for tissue regeneration in the treatment of periodontal diseases (Veronese et al, 1999) and as guides for peripheral nerve regeneration in an experimental animal model (Langone et al, 1995). In our previous work we have demonstrated that scaffolds composed of poly[(ethyl phenylalanato) 1.4 (ethyl glycinato) 0.6 phosphazene] (PPhe-GlyP) and prepared by an electrospinning method support in vitro adhesion and growth of endothelial cells and may be a useful tool for the construction of small blood vessels (Carampin et al, 2007). Starting from these findings, in this work we have verified whether PPhe-GlyP scaffolds obtained from either solvent casting or electrospinning methods could represent a suitable material for bone tissue engineering purposes.…”