Synthesis and evaluation of new phosphonic acid‐functionalized acrylamides with potential biomedical applications

Abstract

Phosphorus‐containing acidic monomers are able to interact with the inorganic phase of mineralized tissues such as enamel, dentin, and bone. From this perspective, three phosphonic acid‐containing acrylamide monomers with different lengths of alkyl chains were synthesized to be used for both self‐etching dental adhesives and mineralized hydrogel scaffolds. Monomers were synthesized by the reaction of α‐aminophosphonates (diethyl aminomethylphosphonate, diethyl 2‐aminobutan‐2‐ylphosphonate, and diethyl 2‐aminooctan‐2‐ylphosphonate) with acryloyl chloride followed by the hydrolysis of phosphonate groups by using trimethylsilyl bromide. The properties such as pH in the range of mild self‐etching adhesives, hydrolytic stability, high rate of copolymerizations with 2‐hydroxyethyl methacrylate (HEMA) and HEMA/glycerol dimethacrylate, giving high‐molecular‐weight polymers on thermal polymerization, and strong decalcification ability of hydroxyapatite make these monomers good candidates for self‐etching adhesives, although no appreciable effect of the number and size of the α‐substituents was observed. Hydrogel scaffolds containing phosphonic acid groups were fabricated, characterized, and mineralized. Altogether, the results suggest that these phosphonic acid‐containing monomers have suitable properties to be used in fabrication of biomaterials for both dental and bone tissue engineering applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2755–2767

Bisphosphonic Acid-Functionalized Cross-Linkers to Tailor Hydrogel Properties for Biomedical Applications

“…Phosphorous-containing polymers have been implemented to improve and accelerate the formation of native tissue both by mimicking the native role of phosphorous groups in the body and by attachment of other bioactive molecules . The hydrogels containing phosphate and phosphonate groups mineralize faster and more completely than analogues lacking the phosphorus-containing groups and also feature better cell adhesion and growth. − In this context, Gemeinhart et al developed a copolymer hydrogel of vinyl phosphonic acid (VPA) and acrylamide and found that at 30% VPA concentration, osteoblast-like cells exhibit better proliferation, adhesion, differentiation, and ability to mineralize the polymer surface than at other concentrations of VPA; other work observed that ethylene glycol methacrylate phosphate-containing poly­(ethylene glycol) (PEG) diacrylate hydrogels promote human mesenchymal stem cells adhesion and spreading; and hydrogels based on a phosphoester–PEG polymer promoted the gene expression of bone-specific markers including type I collagen and osteonectin without the addition of growth factors or other biological agents, compared with pure PEG-based gels …”