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Hydrophobic Salt-modified Nafion for Enzyme Immobilization and Stabilization
Published on: July 11, 2012
β-Cyclodextrin grafted polyethyleneimine hydrogel immobilizing hydrophobically modified glucose oxidase
1Polymer Chemistry, Material Chemistry Department, Uppsala University, S-751 21 Uppsala, Sweden.
International Journal of Biological Macromolecules
|February 22, 2011
Summary
Researchers developed glucose-responsive hydrogels by immobilizing glucose oxidase (GOD) into polyethyleneimine hydrogels. These smart hydrogels show controlled release of contents based on glucose levels, useful for drug delivery applications.
Area of Science:
- Biomaterials Science
- Polymer Chemistry
- Drug Delivery Systems
Background:
- Developing smart hydrogels that respond to physiological stimuli like glucose is crucial for advanced drug delivery.
- Glucose oxidase (GOD) enzyme-based systems offer a promising avenue for glucose-sensitive material design.
- Polyethyleneimine (PEI) and β-cyclodextrin (βCD) composites provide a versatile hydrogel platform.
Purpose of the Study:
- To create glucose-responsive hydrogels by immobilizing glucose oxidase (GOD) into β-cyclodextrin grafted polyethyleneimine (PEI-βCD) hydrogels.
- To investigate the effect of hydrophobic modification of GOD on its immobilization and activity within the hydrogel matrix.
- To evaluate the glucose-induced swelling and release characteristics of the developed hydrogels.
Main Methods:
- Hydrophobically modified glucose oxidase (HmGOD) was synthesized by reacting GOD with palmitic acid-N-hydroxysuccinimide ester.
- The degree of hydrophobic modification was quantified using the trinitrobenzene sulfonic acid (TNBS) assay.
- The swelling behavior and release kinetics of fluorescein isothiocyanate dextran from the HmGOD-loaded PEI-βCD hydrogels were measured at varying glucose concentrations.
Main Results:
- Hydrophobic modification attached approximately five palmitic acid molecules per GOD molecule, retaining about 76% of native enzyme activity.
- HmGOD-loaded hydrogels exhibited increased swelling ratios from 960% to 1190% within 24 hours as glucose concentration increased from 0 to 100 mg/dL.
- The release percentage of fluorescein isothiocyanate dextran over 48 hours significantly increased from 53% to 89% with rising glucose concentrations.
Conclusions:
- The PEI-βCD hydrogels successfully incorporated HmGOD, demonstrating significant glucose-responsive swelling and drug release capabilities.
- The enzymatic production of gluconic acid, leading to hydrogel protonation and swelling, is the primary mechanism for enhanced release.
- These glucose-responsive hydrogels show potential for applications requiring controlled release triggered by glucose levels, such as in diabetes management or biosensing.
