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Gelation studies of a cellulose-based biohydrogel: The influence of pH, temperature and sterilization

Paper ID Volume ID Publish Year Pages File Format Full-Text
1870 93 2009 10 PDF Available
Title
Gelation studies of a cellulose-based biohydrogel: The influence of pH, temperature and sterilization
Abstract

The present paper investigates the rheological properties of silated hydroxypropylmethylcellulose (Si-HPMC) biohydrogel used for biomaterials and tissue engineering applications. The general property of this modified cellulose ether is the occurrence of self-hardening due to silanol condensation subsequent to a decrease in pH (from 12.4 to nearly 7.4). The behavior of unsterilized and sterilized Si-HPMC solutions in diluted and concentrated domains is first described and compared. In addition, the influence of physiological parameters such as pH and temperature on the rate of the gelation process is studied. In dilute solution, the intrinsic viscosity ([η]) of different pre-steam sterilization Si-HPMC solutions indicates that macromolecular chains occupy a larger hydrodynamic volume than the post-steam sterilization Si-HPMC solutions. Although the unsterilized Si-HPMC solutions demonstrate no detectable influence of pH upon the rheological behavior, a decrease in the limiting viscosities (η0) of solutions with increasing pH is observed following steam sterilization. This effect can be explained by the formation of intra- and intermolecular associations during the sterilization stage originating from the temperature-induced phase separation. The formation of Si-HPMC hydrogels from injectable aqueous solution is studied after neutralization by different acid buffers leading to various final pHs. Gelation time (tgel) decreases when pH increases (tgel varies from 872 to 11 s at pH 7.4 and 11.8, respectively). The same effect is observed by increasing the temperature from 20 to 45 °C. This is a consequence of the synergistic effect of the increased reaction rate and acid buffer diffusion. pH and temperature are important parameters in the gelation process and their influence is a key factor in controlling gelation time. By adapting the gel parameters one could propose hydrogels with cross-linking properties adapted to clinical applications by controlling the amount of pH of neutralization and temperature.

Keywords
Self-cross-linkable hydrogels; In situ gelling; Hydroxypropylmethylcellulose; Silanization; Rheology
First Page Preview
Gelation studies of a cellulose-based biohydrogel: The influence of pH, temperature and sterilization
Publisher
Database: Elsevier - ScienceDirect
Journal: Acta Biomaterialia - Volume 5, Issue 9, November 2009, Pages 3423–3432
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering