# Collagen-Based 3D Scaffolds from Sea Urchin Food Waste for Skeletal Muscle Tissue Engineering

## TL;DR

This paper explores using collagen from sea urchin food waste to create 3D muscle tissue models, aiming to reduce animal testing and support personalized therapies.

## Contribution

The novelty lies in using sea urchin-derived collagen from food waste to engineer 3D skeletal muscle tissue models.

## Key findings

- Collagen-based scaffolds from sea urchin waste supported C2C12 myoblast infiltration and viability.
- CollMA scaffolds showed myogenic commitment with Pax7/MyoD expression patterns.
- The models could potentially replace animal testing in skeletal muscle research.

## Abstract

Skeletal muscle comprises around 40% of total body mass in mammals. It consists of bundles of muscle fibers surrounded by an extracellular matrix providing structural support, with collagen as the principal component. Several disorders can affect skeletal muscle, many being rare genetic diseases currently lacking specific therapies. Animal models are widely used in biomedical research and the pharmaceutical industry to study disease mechanisms and develop new treatments. However, there is a growing need for alternative approaches that reduce animal use while maintaining physiological relevance. In this context, the pharmaceutical sector is increasingly adopting the One Health framework, which recognizes the interconnection between human health, animal health, and environmental sustainability. This study proposes two 3D skeletal muscle tissue models. These collagen-based models mimic the muscle extracellular matrix using sea urchin collagen, supporting muscle cell growth, infiltration, and differentiation. In the future, such tissue models may enable patient-derived muscle constructs for evaluating precision and personalized therapies, reducing animal testing. Additionally, utilizing collagen from food industry waste aligns with circular economy principles.

Preclinical investigations involving in vivo animal studies, are considered a crucial and mandatory step in pharmacological industry regulations. In recent years, as the ethical concerns associated with animal experimentation are becoming more relevant, substantial research efforts have been directed towards the development of novel in vitro methodological approaches aimed at minimizing the utilization of animals. Among those, three-dimensional (3D) cell culture systems have become one of the most promising substitutes for animal models. Skeletal muscle can be affected by genetic disorders and injuries. In this study, two types of 3D scaffolds (Coll and CollMA), prepared starting from a fibrillar collagen suspension extracted from sea urchin food waste, were used as platforms for the generation of 3D skeletal muscle tissue models. The scaffolds were cellularized with C2C12 myoblasts. As the culture period progressed, C2C12 cells gradually infiltrated and were viable throughout both scaffold types, establishing a multilayered cellular population. In the CollMA scaffold, the reciprocal Pax7/MyoD expression pattern suggests a progression of myoblasts towards myogenic commitment. Taken together, our results, although preliminary, suggest that sea urchin–derived collagen matrix represents a promising scaffold for skeletal muscle tissue engineering.