Zwitterionic Tissue Expanders Reduce Infection and Fibrosis for Enhanced Biocompatibility

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Tissue Engineering

Background:

• Current osmotic tissue expanders face challenges like protein adsorption, bacterial colonization, and fibrotic encapsulation.
• These issues compromise device performance and patient outcomes in reconstructive surgery.

Purpose of the Study:

• To synthesize and characterize novel zwitterionic hydrogels for enhanced osmotic tissue expansion.
• To evaluate the hydrogels' resistance to biological fouling and their in vivo tissue response.

Main Methods:

• Zwitterionic hydrogels were synthesized using methyl methacrylate, n-vinyl pyrrolidone, and varying percentages of [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA).
• In vitro assays assessed swelling capacity, mechanical integrity, protein adsorption (lysozyme, fibrinogen, BSA), and bacterial (Staphylococcus aureus) attachment.
• Subcutaneous implantation in Sprague Dawley rats evaluated fibrous capsule formation over 14 days.

Main Results:

• SBMA incorporation significantly increased hydrogel swelling capacity while maintaining mechanical integrity.
• Zwitterionic hydrogels demonstrated superior resistance to protein adsorption and reduced bacterial attachment compared to controls.
• Implanted hydrogels with 5-30% SBMA formed significantly thinner fibrous capsules, with 30% SBMA yielding the most uniform matrix.

Conclusions:

• Zwitterionic hydrogels represent a significant advancement for osmotic tissue expansion technology.
• These materials effectively address key limitations of current devices by reducing biological fouling and fibrotic encapsulation.
• The developed zwitterionic hydrogels show potential for improving clinical outcomes and reducing revision surgeries in reconstructive procedures.