Highly Conductive, Adhesive and Biocompatible Hydrogel for Closed-Loop Neuromodulation in Nerve Regeneration

Area of Science:

• Biomaterials Science
• Neuroscience
• Bioelectronics

Background:

• Conductive hydrogels are crucial for bioelectronic applications like neural interfacing and neuromodulation.
• Existing hydrogels face challenges in balancing conductivity, mechanical properties, and biocompatibility, often requiring high filler concentrations.

Purpose of the Study:

• To develop a multifunctional conductive hydrogel (PAACP) with superior stretchability, bioadhesion, and conductivity.
• To address the limitations of traditional conductive hydrogels in achieving optimal performance characteristics.

Main Methods:

• Engineered a polyacrylamide-poly(acrylic acid) (PAM-PAA) matrix hydrogel.
• Incorporated polydopamine-modified carbon nanotubes (CNT-PDA) at a low concentration (0.33 wt %).
• Utilized catechol and NHS ester functional groups for enhanced tissue adhesion.

Main Results:

• Achieved high conductivity (9.52 S/m) with minimal CNT-PDA content.
• Demonstrated excellent mechanical properties: low tensile modulus (~100 kPa), high stretchability (~1000%), and high toughness (7.33 kJ m^-2).
• Exhibited strong tissue adhesive strength (107.14 kPa).
• Successfully used as a suture-free cuff electrode for sciatic nerve interfacing and in a closed-loop system for nerve repair, enhancing functional recovery.

Conclusions:

• The PAACP hydrogel offers a promising platform for advanced bioelectronic devices and neural repair.
• This material overcomes key limitations in conductive hydrogel development, enabling suture-free implantation and effective neuromodulation.
• The study presents a strategy for personalized, real-time feedback-driven nerve regeneration and functional recovery.