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Related Experiment Video

Updated: May 20, 2026

Air Filter Devices Including Nonwoven Meshes of Electrospun Recombinant Spider Silk Proteins

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Published on: May 8, 2013

Ion Electrodiffusion Governs Silk Electrogelation.

Nikola Kojic¹, Matthew J Panzer, Gary G Leisk

¹Department of Biomedical Engineering, Tufts University, Medford MA, 02155.

|July 24, 2012

Summary

Silk electrogelation uses electric current to form a gel (E-gel) by altering pH. Ion electrodiffusion governs this process, enabling predictable control over E-gel formation for various applications.

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Electrospinning Fundamentals: Optimizing Solution and Apparatus Parameters

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Published on: January 21, 2011

Area of Science:

Biomaterials Science
Electrochemistry
Polymer Chemistry

Background:

Silk fibroin solutions can transition to a gel state (E-gel) under an electric current.
This electrogelation is driven by local pH changes from water electrolysis at electrodes.
Silk fibroin gels form when the local pH drops below its isoelectric point (pI=4.2).

Purpose of the Study:

To investigate the mechanism of silk electrogelation.
To develop a model explaining the pH distribution and E-gel growth during electrogelation.
To validate the predictive capability of the model for controlling E-gel formation.

Main Methods:

Constructed an experimental system to measure E-gel growth and pH distribution.
Developed a finite-element ion electrodiffusion model.
Solved ion electrodiffusion equations using experimental E-gel and voltage data.
Validated model predictions experimentally.

Main Results:

Observed a distinct rectangular pH profile (pH~4 within gel, pH~10 in solution).
The ion electrodiffusion model accurately replicated the experimental pH profile.
Model successfully predicted currents required for specific E-gel growth rates, which were experimentally confirmed.

Conclusions:

Ion electrodiffusion is the primary mechanism controlling local pH changes and E-gel growth.
The developed model provides a predictable framework for understanding and controlling silk electrogelation.
This work offers insights for fundamental research and practical applications of silk-based E-gels.