Hydrolytically degradable polyrotaxane hydrogels for drug and cell delivery applications

Pradal, Clementine, Grondahl, Lisbeth and Cooper-White, Justin J. (2015) Hydrolytically degradable polyrotaxane hydrogels for drug and cell delivery applications. Biomacromolecules, 16 1: 389-403. doi:10.1021/bm501615p

Author Pradal, Clementine
Grondahl, Lisbeth
Cooper-White, Justin J.
Title Hydrolytically degradable polyrotaxane hydrogels for drug and cell delivery applications
Journal name Biomacromolecules   Check publisher's open access policy
ISSN 1526-4602
Publication date 2015-01-12
Sub-type Article (original research)
DOI 10.1021/bm501615p
Open Access Status
Volume 16
Issue 1
Start page 389
End page 403
Total pages 15
Place of publication Washington, DC, United States
Publisher American Chemical Society
Collection year 2016
Language eng
Abstract Self-assembled pseudopolyrotaxane (PPR) hydrogels formed from Pluronic polymers and α-cyclodextrin (α-CD) have been shown to display a wide range of tailorable physical and chemical properties that may see them exploited in a multitude of future biomedical applications. Upon the mixing of both components, these self-assembling hydrogels reach a metastable thermodynamic state that is defined by the concentrations of both components in solution and the temperature. However, at present, their potential is severely limited by the very nature by which they form and hence also disassemble. Even if the temperature is kept constant, PPR hydrogels will dissociate and collapse within a few hours when immersed in a liquid (such as cell culture media) that contains a lower concentrations of, or no, Pluronic or α-CD due to differences in chemical potential driving dissolution. In this article, an enzymatically mediated covalent cross-linking function and branched eight-arm poly(ethylene glycol) (PEG) were thus introduced into the PPR hydrogels to improve their robustness to such environmental changes. The eight-arm PEG also acted as an end-capping group to prevent the dethreading of the α-CD molecules. The covalent cross-linking successfully extended the lifetime of the hydrogels when placed in cell culture media from a few hours to up to 1 week, with the ability to control the degradation rate (now initiated by hydrolysis of the introduced ester bonds and not by dissolution) by changing the amount of eight-arm PEG present in the hydrogels. Highly tunable hydrogels were obtained with an elastic modulus between 20 and 410 kPa and a viscous modulus between 150 Pa and 22 kPa by varying the concentrations of α-CD and eight-arm PEG. Sustained release of a model drug from the hydrogels was achieved, and viability of mouse fibroblasts encapsulated in these hydrogels was assessed. These self-assembling, hydrolytically degradable, and highly tunable hydrogels are seen to have potential applications in tissue engineering relying on controlled drug or cell delivery to sites targeted for repair.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

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