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Published on: October 29, 2013
Anionic and cationic dextran hydrogels for post-loading and release of proteins.
Joris P Schillemans1, Ellen Verheyen, Arjan Barendregt
1Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands.
Summary
This study demonstrates efficient post-loading and release of proteins in dextran hydrogels using reversible electrostatic interactions. This method ensures protein integrity and offers a versatile approach for various protein types.
Area of Science:
- Biomaterials Science
- Polymer Chemistry
- Protein Chemistry
Background:
- Chemically crosslinked dextran hydrogels are promising for biomedical applications.
- Protein incorporation into hydrogels often involves complex procedures or can lead to protein modification.
- Developing methods for efficient and non-damaging protein loading is crucial.
Purpose of the Study:
- To investigate the post-loading and release of proteins in dextran hydrogels via reversible electrostatic interactions.
- To evaluate the impact of hydrogel properties and loading conditions on protein loading efficiency and distribution.
- To assess the integrity of loaded proteins after release.
Main Methods:
- Synthesis of charged dextran hydrogels (negatively charged with methacrylic acid, positively charged with dimethylaminoethyl methacrylate).
- Post-loading of proteins (cytochrome C, BSA, myoglobin) into hydrogels under varying conditions (ionic strength, pH, network charge, crosslink density).
- Protein release studies triggered by buffer exchange and analysis of released protein integrity using ESI-MS.
Main Results:
- Quantitative protein absorption was achieved, with loading efficiency dependent on network charge (optimal at 100-150 μmol/g) and crosslink density (higher loading at lower density).
- Higher ionic strength during loading resulted in more homogenous protein distribution.
- Controlled protein release was observed, with quantitative release in 1 M NaCl, indicating no irreversible immobilization or aggregation.
- Post-loading preserved protein integrity, preventing oxidation observed with in-situ loading.
Conclusions:
- Post-loading of proteins into dextran hydrogels using reversible electrostatic interactions is an effective strategy.
- This method is suitable for proteins with negative, positive, or neutral charges at physiological pH.
- The loading process does not chemically modify the proteins, preserving their native structure and function.
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