Electroconductive hydrogels for spinal cord regeneration

Introduction
Spinal cord injury (SCI) is a severe condition that compromises the central nervous system, leading to disability and medical complications [1]. Current treatments fail to fully address SCI due to limited neural regeneration and the complex pathophysiology of the disease. Neural stem cell (NSC) transplantation offers therapeutic potential by promoting tissue repair [1–2]; however, direct injection often results in poor survival and integration [2]. To overcome these limitations, hydrogels can be used as scaffolds that mimic the physical and biochemical properties of neural tissue [2–3]. Incorporating electroconductive polymers may further enhance neuronal differentiation, improving therapeutic outcomes [3]. This work presents the development of electroconductive hydrogels for NSC delivery in SCI treatment. Agarose and gelatin were selected as the biocompatible matrix, while polypyrrole (PPy) and polyaniline (PAni) were introduced for their conductive and antioxidant properties [3–4].

Methods
Agarose-gelatin (AgaGel) hydrogels were prepared by mixing both polymers at 60 °C and cooling to room temperature. Conductive versions were obtained by adding aniline or pyrrole to the hot blend, followed by oxidative polymerization at 4 °C. Residual monomers were removed by washing. Hydrogels were characterized using rheology, swelling tests, conductivity measures, FT-IR, and SEM.

Results
Different AgaGel formulations were created by varying polymer concentrations. Agarose increased mechanical strength, while gelatin improved elasticity but reduced stability at high levels. An optimal ratio was defined to achieve a storage modulus between 100 and 1000 Pa, ideal for NSC support. Conductivity and porosity were enhanced by incorporating PPy or PAni without compromising structural integrity.

Conclusions
The proposed strategy enabled the creation of electroconductive hydrogel scaffolds suitable for NSC-based spinal cord regeneration. The combined bioactivity and conductivity provide a promising platform for enhancing SCI therapies.