Covalent Modification of Synthetic Hydrogels with Bioactive Proteins via Sortase-Mediated Ligation

Biomacromolecules. 2015 Aug 10;16(8):2316-26. doi: 10.1021/acs.biomac.5b00549. Epub 2015 Jul 10.


Synthetic extracellular matrices are widely used in regenerative medicine and as tools in building in vitro physiological culture models. Synthetic hydrogels display advantageous physical properties, but are challenging to modify with large peptides or proteins. Here, a facile, mild enzymatic postgrafting approach is presented. Sortase-mediated ligation was used to conjugate human epidermal growth factor fused to a GGG ligation motif (GGG-EGF) to poly(ethylene glycol) (PEG) hydrogels containing the sortase LPRTG substrate. The reversibility of the sortase reaction was then exploited to cleave tethered EGF from the hydrogels for analysis. Analyses of the reaction supernatant and the postligation hydrogels showed that the amount of tethered EGF increases with increasing LPRTG in the hydrogel or GGG-EGF in the supernatant. Sortase-tethered EGF was biologically active, as demonstrated by stimulation of DNA synthesis in primary human hepatocytes and endometrial epithelial cells. The simplicity, specificity, and reversibility of sortase-mediated ligation and cleavage reactions make it an attractive approach for modification of hydrogels.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Cysteine Endopeptidases / chemistry
  • DNA / biosynthesis*
  • DNA / drug effects
  • Endometrium / cytology
  • Endometrium / drug effects
  • Epidermal Growth Factor / administration & dosage
  • Epidermal Growth Factor / chemistry*
  • Epithelial Cells / drug effects
  • Female
  • Hepatocytes / drug effects
  • Humans
  • Hydrogels / administration & dosage
  • Hydrogels / chemical synthesis
  • Hydrogels / chemistry*


  • Hydrogels
  • Epidermal Growth Factor
  • DNA
  • Cysteine Endopeptidases