Effect of hydrophilicity and agmatine modification on degradation of poly(propylene fumarate-co-ethylene glycol) hydrogels.
We synthesized positively charged biodegradable hydrogels with different poly(propylene fumarate-co-ethylene glycol) [P(PF-co-EG)] block copolymers and agmatine-modified poly(ethylene glycol)-tethered fumarate [Agm-PEGF] by radical crosslinking and investigated the effect of copolymer composition and agmatine modification on their degradation. Hydrogels were incubated in phosphate-buffered saline (PBS) at 37 degrees C with periodic PBS changes. All hydrogels experienced a slight mass loss over 4 weeks, ranging from 10-20%. Hydrogels with a molar ratio of ethylene glycol repeating units to propylene fumarate repeating units (EG/PF) of 9.3 degraded faster than hydrogels with an EG/PF ratio of 0.6. Agmatine-modified hydrogels degraded faster than unmodified hydrogels. The weight swelling ratio of the hydrogels at pH 7 increased over 4 weeks while increases in the EG/PF ratio and agmatine modification showed greater swelling. After 2 weeks, degraded hydrogels swollen at pH 3 demonstrated significantly lower weight swelling ratios than at pH 5, 7, and 9. Our results suggest that the hydrophilicity of the P(PF-co-EG) copolymer and agmatine modification have a small effect on the degradation of P(PF-co-EG) hydrogels.
Tanahashi
Kazuhiro
K
Department of Bioengineering, Rice University, MS-142, P.O. Box 1892, Houston, Texas 77251-1892, USA.
Mikos
Antonios G
AG
D000376:Agmatine / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000378:metabolism*; D011126:Polypropylenes / Q000737:chemistry* / Q000378:metabolism*; D014867:Water / Q000737:chemistry*
D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D020100:Hydrogels; D011126:Polypropylenes; C115157:poly(propylene fumarate-co-ethylene glycol); D014867:Water; D011092:Polyethylene Glycols; D000376:Agmatine