Enzyme-Free Production of Silk Hydrogels

  • Author: ChemistryViews.org
  • Published: 28 July 2019
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
  • Source / Publisher: Advanced Healthcare Materials/Wiley-VCH
thumbnail image: Enzyme-Free Production of Silk Hydrogels

Many proteins or polymers can be crosslinked to form hydrogels, which can be used, e.g., in medicine. Often, enzymes are used for the preparation of such hydrogels, for example, from hyaluronic acid, gelatin, alginate, chitosan, or silk fibroin. However, some of the enzyme remains in the hydrogel products. This can cause an immunological response in the body.

David L. Kaplan, Tufts University, Medford, MA, USA, and colleagues have developed a method for the enzyme-free synthesis of chemically crosslinked silk fibroin hydrogels for biomedical applications. Silk fibroin protein is promising for medicine due to its biocompatibility, controllable biodegradability, mechanical strength, and mild immunological response. The team used a Fenton reaction to chemically crosslink the fibroin. This reaction is based on a redox reaction between Fe2+ and H2O2 that generates a reactive hydroxyl radical (OH). These radicals initiate crosslinking reactions, in this case, the formation of dityrosine bonds in the protein through the oxidation of tyrosine residues.

The Fe3+ ions formed during the reaction can interact with silk fibroin and trigger the formation of β‐sheet structures (pictured in red). These β-sheet structures scatter light and make the hydrogel opaque. If the reaction is performed in the presence of the iron-chelating agent ethylenediaminetetraacetic acid (EDTA), fewer Fe3+ ions can interact with the protein and the hydrogel remains transparent.

This can be important for applications in ophthalmology, optical sensing, and diagnostics. According to tests on mouse cells, the hydrogels prepared by the Fenton reaction are biocompatible.


Article Views: 1002

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

Bookmark and Share

If you would like to reuse any content, in print or online, from ChemistryViews.org, please contact us first for permission. more


ChemistryViews.org on Facebook

ChemistryViews.org on Twitter ChemistryViews.org on YouTube ChemistryViews.org on LinkedIn Sign up for our free newsletter

A product of ChemPubSoc Europe (16 European Chemical Societies)published by Wiley-VCH