Synthesis and characterization of a novel degradable phosphate-containing hydrogel

Biomaterials. 2003 Oct;24(22):3969-80. doi: 10.1016/s0142-9612(03)00280-1.


A phosphate-containing and photocrosslinkable polymer, poly(ethylene glycol) di-[ethyl phosphatidyl (ethylene glycol) methacrylate], "PhosPEG-dMA", was synthesized. As a water-soluble macromer, PhosPEG-dMA is suitable for in situ injection and cell-encapsulation by light-induced gelation to produce a novel biocompatible and biodegradable hydrogel for application to cartilage and bone tissue engineering. 1H-NMR, MALDI-TOF mass spectrometry, and elemental analysis were performed to characterize the macromer. Fifteen and 20% (w/v) PhosPEG gels were photopolymerized using UV light with 0.05% photoinitiator. The swelling and water content of the hydrogels was studied and the crosslinking efficiency (density) of the macromers was simulated based on the Peppas-Merrill model. Torsional mechanical analysis of the gels demonstrated a viscoelastic characteristic with high elasticity. The results indicated that, with the fixed PEG-segment size, the greater strength and water-content of the gels depend on the higher crosslinking density. Degradation experiments revealed a linear dry-weight loss of 22.88% and 16.08% from 15% and 20% PhosPEG gels after 9 weeks. The 31P-NMR detected the signals of both phosphate and phosphoric acid in the degrading systems (the gel bulks and the supernatants). Finally, human mesenchymal stem cells (hMSC) were encapsulated into PhosPEG Gel constructs and remained viable as qualitatively demonstrated by "Live/Dead" cell staining assay and MTT assay. The cell-encapsulation efficiency was determined by the characterization of DNA content in each gel construct and the semi-quantitative analysis of the cell viability was also performed by the DNA assay combined with MTT assay.

MeSH terms

  • Acrylates / chemistry*
  • Biocompatible Materials / chemical synthesis
  • Biocompatible Materials / chemistry*
  • Cell Survival
  • Coloring Agents / pharmacology
  • Cross-Linking Reagents / pharmacology
  • Humans
  • Hydrogel, Polyethylene Glycol Dimethacrylate / chemical synthesis
  • Hydrogel, Polyethylene Glycol Dimethacrylate / chemistry*
  • Light
  • Magnetic Resonance Spectroscopy
  • Methacrylates
  • Models, Chemical
  • Polyethylene Glycols / chemistry*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Stem Cells / cytology
  • Tetrazolium Salts / pharmacology
  • Thiazoles / pharmacology
  • Time Factors
  • Tissue Engineering
  • Ultraviolet Rays
  • Water / chemistry


  • Acrylates
  • Biocompatible Materials
  • Coloring Agents
  • Cross-Linking Reagents
  • Methacrylates
  • Tetrazolium Salts
  • Thiazoles
  • poly(ethylene glycol)-dimethacrylate
  • Water
  • Hydrogel, Polyethylene Glycol Dimethacrylate
  • Polyethylene Glycols
  • thiazolyl blue