Synthesis and Characterization of Novel Poly[(organo)phosphazenes] with Cell-Adhesive Side Groups

Abstract

There is a need to develop new scaffold materials with controlled surface properties for tissue engineering applications. For that purpose novel biodegradable poly[(organo)phosphazenes] were synthesized. A cell-binding molecule, galactose, was introduced via a spacer, either 6-aminohexanol (AH) or poly(ethylene glycol) (PEG; M(w) = 3400). Some polymers were substituted with an additional PEG chain of different molecular weights (M(w) = 750 or 5000). The polyphosphazene derivatives were characterized by 1H NMR. T(g) and T(m) were determined using differential scanning calorimetry. A detailed surface analysis of the polymers using X-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS), and dynamic contact angle (DCA) measurements was performed. Typical backbone and side chain fragments were detected by SIMS and confirmed the polymer composition. Compared to that of the reference polymer (having only amino acid ester side groups), an increased value of the specific ether carbon groups from PEG confirmed the enrichment of PEG at the surface of PEG-Gal polymers. However, the values were lower than expected. DCA studies showed that the galactose moieties were present at the surface after exposure to an aqueous environment. XPS results confirmed the similarity between experimental and theoretical values for the AH-Gal polymers. This indicated the presence of galactose moieties at the surface, which was confirmed by the DCA data because the contact angles were low compared to those of the other polymers.

Phosphorus-nitrogen compounds: Part 15. Synthesis, anisochronism and the relationship between crystallographic and spectral data of monotopic spiro-crypta phosphazenes

“…The reactions of hexachlorocyclotriphosphazatriene, N 3 P 3 Cl 6 , which is known as the standard compound in the field of phosphazene and polyorganophosphazene chemistry, [1][2][3][4][5] with bulky bifunctional reagents lead to the formation of spiro-, ansa-, spiro-ansa-, binoarchitectures and cyclolinear or cyclomatrix polymers. [6][7][8][9] The different substituents that are bonded to phosphorus atoms are very effective for the determination of the physical and chemical properties of new phosphazene derivatives and polyorganophosphazenes.…”

Biodegradable Polyphosphazene Scaffolds for Tissue Engineering

“…914-918). Furthermore, side-group modification with cell adhesive groups such as galactose using various spacers has resulted in a new class of polymers with increased protein interaction and biocompatibility (Heyde et al, 2007(Heyde et al, , 2008. This ability to create a large group of polymers with the required properties renders polyphosphazenes more versatile than some of the polymer systems available for tissue engineering applications.…”

“Click Chemistry” as a Facile Approach to the Synthesis of Polyphosphazene Glycopolymers

“…[7][8][9][10][11][12][13][14][15] Polyphosphazene derivatives with carbohydrates as side groups are of particular interest for probes or effectors in biological processes involving carbohydrate/protein interactions. [16][17][18][19][20][21][22][23] For example, Heyde et al introduced galactose to polyphosphazene using either 6-aminohexanol or poly(ethylene glycol) as a spacer, and demonstrated that the galactose pendants were able to selectively bind lectin. A large proportion of galactose was favorable for multivalent carbohydrate/protein interactions.…”

“…A large proportion of galactose was favorable for multivalent carbohydrate/protein interactions. [19,20] Yang et al synthesized galactosylated polyphosphazene with a 4.9% degree of substitution from poly{[2-(2-aminoethoxy)ethoxy]phosphazene} and lactobionic acid. [23] They found that the galactose pendants could be used as targeting ligands and showed specific affinity to the asialoglycoprotein receptor.…”