Synthesis and characterization of novel poly[(organo)phosphazenes] with cell-adhesive side groups.
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.
Heyde
Mieke
M
Polymer Chemistry and Biomaterials Research Group, Ghent University, 9000 Ghent, Belgium.
Moens
Monique
M
Van Vaeck
Luc
L
Shakesheff
Kevin M
KM
Davies
Martyn C
MC
Schacht
Etienne H
EH
D002448:Cell Adhesion; D005690:Galactose / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D013057:Spectrum Analysis; D013499:Surface Properties; D023822:Tissue Engineering
D009943:Organophosphorus Compounds; D011108:Polymers; C108974:poly(phosphazene); D011092:Polyethylene Glycols; D005690:Galactose