Characterization of enzymatically gellable, phenolated linear poly(ethylene glycol) with different molecular weights for encapsulating living cells

• Phenolated poly(ethylene glycol) with different molecular weights was prepared.
• Horseradish peroxidase was employed as biocatalyst for the preparation of hydrogels.
• Physicochemical properties of the hydrogels were tuned by PEG molecular weight.
• Rapid enzymatic hydrogel formation showed the potential in in situ hydrogelation.
• Mammalian cells encapsulated in the hydrogels retained high viability.

Enzymatic hydrogelation has received much attention due to the high biocompatibility and the ease of control of reaction kinetics under physiological conditions. In particular, horseradish peroxidase (HRP)-mediated phenol coupling reaction has great potential for developing in situ hydrogelation systems. Herein, we report the HRP-catalyzed preparation and characterization of hydrogels composed of a terminally bis-phenolated linear poly(ethylene glycol) (PEG-Ph-OH) with different molecular weights (Mws 3100, 8800, 11,000, 20,000 g/mol). The gelation time of polymer solution can be controlled in the range from few second to few minute, suggestion that the PEG-Ph-OH has a potential as a in situ forming hydrogel. In addition, the physicochemical properties of the hydrogels, such as swelling ratio, mesh size and mechanical property, were controlled by the molecular weight of the PEG-Ph-OH. The results could be attributed to the alteration in the cross-linking density by the variation of molecular weight of the gel precursor. Furthermore, the viability of mammalian cells encapsulated in the PEG-Ph-OH hydrogels was approximately 90%. These results indicate that PEG-Ph-OH has potential for biomedical applications including tissue engineering.