# Carbon Nanotube Hydrogels Reveal Threshold‐Dependent Regulation of Neuroblastoma Cell Growth and Maturation by Mechanical and Chemical Factors

## TL;DR

This study shows how mechanical and chemical properties of carbon nanotube hydrogels can control the growth and maturation of neuroblastoma cells for nerve regeneration.

## Contribution

The paper introduces PVA/CNT hydrogels with 75% CNT loading and identifies threshold-dependent factors for cell coverage and maturation.

## Key findings

- CNT concentration above 60% or coatings enhance cell coverage by improving CNT–cell interactions.
- Young's modulus dominates cell growth below a specific threshold, achieving up to 50% coverage.
- Pore sizes of 100–250 μm increased cell coverage to >70% and upregulated the TUBB3 maturity marker.

## Abstract

Carbon nanotube (CNT)‐based hydrogels have the potential to serve as 3D platforms for nerve regeneration. However, the interplay between different cues governing the formation of a complex tissue‐like cellular structure is still ambiguous. Herein, two approaches are adopted to develop PVA/CNT hydrogels using phase inversion method and low kinetic gelation, enabling unprecedented CNT loading capacity (75% w/w) without compromising their elasticity. By controlling key factors affecting cell coverage and maturation, including Young's modulus (YM), CNT concentration, and pore size, distinct thresholds are identified where these factors dominate cell coverage. Results demonstrated that when CNT exceeds 60% w/w or a coating is applied to enhance CNT–cell interaction, CNT effect dominates, increasing cell coverage with increasing CNT concentration. However, below a specific YM threshold, YM dominates cell growth, covering up to 50% of the scaffold surface regardless of CNT concentration or exposure. Lastly, controlling the pore size to 100–250 μm further increased cell coverage to >70%, breaking through previous plateau and upregulating TUBB3 maturity marker. Additionally, certain key factors are seen to synergistically codominate in determining cell growth.

Poly(vinyl alcohol)/carbon nanotube (PVA/CNT) hydrogels with unprecedented CNT loading (75% w/w) were engineered as 3D scaffolds for nerve regeneration. By tuning Young's modulus (YM), CNT concentration, and pore size, distinct thresholds controlling cell coverage were identified. Optimized scaffolds achieved > 70% coverage and upregulated β‐3‐tubulin (TUBB3), highlighting synergistic cues driving neuronal maturation.© 2025 WILEY‐VCH GmbH