3D Bioprinted Cellulose/Collagen-Based Drug-Eluting Fillers for the Treatment of Deep Tunneling Wounds

Academic Background

Deep tunneling wounds are complex injuries that form beneath the skin surface, varying in shape and size, and may have twists and turns, making treatment extremely challenging. Current wound care solutions primarily target superficial wounds, while untreated tunneling wounds can lead to severe health issues. Therefore, developing a material that can effectively fill and promote the healing of deep tunneling wounds is of great significance. This study aims to address this challenge by fabricating tunnel wound fillers (TWFs) using natural polymers such as cellulose and collagen to mimic the dermal extracellular matrix.

Source of the Paper

The research was conducted by Mano Govindharaj, Noura Al Hashimi, Soja S. Soman, Jiarui Zhou, Safeeya Alawadhi, and Sanjairaj Vijayavenkataraman. The research team is affiliated with the Vijay Lab at New York University Abu Dhabi and the Department of Mechanical and Aerospace Engineering at the Tandon School of Engineering, New York University. The paper was published online on October 22, 2024, in the journal Bio-design and Manufacturing.

Research Process

1. Extraction of Cellulose Microfibers (CMFs) and Collagen Coating

The study first extracted cellulose microfibers (CMFs) from banana stems and purified them through chemical and mechanical methods. Subsequently, CMFs were coated with fish skin-derived collagen to enhance their bioactivity. This step was validated using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy, confirming the successful coating of collagen on CMFs.

2. Bio-Ink Preparation and 3D Printing

The research team prepared three bio-inks with varying CMF contents (25, 50, and 75 mg) and tested their rheological properties. The results showed that the 50 mg CMF bio-ink exhibited the best 3D printing performance. The TWFs were then fabricated using a RegenHU 3D Discovery bioprinter, and the printed constructs were stabilized through ionic crosslinking (using CaCl₂).

3. Drug Release and Cell Loading

The TWFs were loaded with the antibiotic drug Baneocin, and their drug release behavior was tested under different pH conditions in vitro. The results showed that the drug release rate was significantly higher in an acidic environment (pH 5) compared to a neutral environment (pH 7). Additionally, the TWFs were loaded with human mesenchymal stem cells (hMSCs), and cell survival and proliferation were verified through Alamar Blue assays and live/dead staining.

4. In Vitro Wound Healing Assay

The study used mouse embryonic fibroblasts (MEFs) in a scratch assay to evaluate the wound-healing potential of the TWFs. The results showed that the CMF/collagen/alginate combination of TWFs almost completely covered the scratched area within 48 hours, demonstrating the best wound-healing effect.

5. Chicken Tissue Model Validation

Finally, the research team created a deep tunneling wound model on chicken breast tissue and inserted the 3D-printed TWFs into the wounds. The results showed that the TWFs exhibited excellent structural stability and flexibility, adapting well to the complex shapes of the wounds and providing a moist environment conducive to healing.

Key Findings

1. Extraction of CMFs and Collagen Coating: SEM, FTIR, and Raman spectroscopy confirmed the successful coating of collagen on CMFs, enhancing their bioactivity.
2. Rheological Properties of Bio-Ink: The 50 mg CMF bio-ink exhibited the best 3D printing performance, making it suitable for fabricating TWFs.
3. Drug Release Behavior: The TWFs showed a higher drug release rate in an acidic environment, making them suitable for use in infected wounds.
4. Cell Survival and Proliferation: The hMSC-loaded TWFs demonstrated significant cell proliferation over seven days, indicating excellent biocompatibility.
5. In Vitro Wound Healing: The CMF/collagen/alginate combination of TWFs almost completely covered the scratched area within 48 hours, showing the best wound-healing effect.
6. Chicken Tissue Model Validation: The TWFs adapted well to the complex shapes of deep tunneling wounds and provided a moist environment conducive to healing.

Conclusion

This study successfully developed a tri-layered drug-eluting filler (TWF) based on cellulose and collagen for the treatment of deep tunneling wounds. The filler exhibited excellent biocompatibility, drug release capability, and wound-healing promotion. Through 3D printing technology, TWFs can be customized according to the shape and size of the wound, demonstrating broad application prospects.

Research Highlights

1. Innovative Materials: The use of cellulose microfibers extracted from banana stems and fish skin-derived collagen is environmentally friendly and sustainable.
2. 3D Printing Technology: The TWFs fabricated through 3D printing can be customized according to the shape and size of the wound, offering high flexibility.
3. Drug Release and Cell Loading: The TWFs can be loaded with antibiotic drugs and stem cells, showing potential for promoting wound healing and regeneration.
4. In Vitro and In Vivo Validation: The effectiveness and applicability of TWFs were validated through in vitro experiments and a chicken tissue model.

Research Value

This study provides an innovative solution for the treatment of deep tunneling wounds, with significant scientific and practical value. Through 3D printing technology, TWFs can be personalized to meet the needs of different patients. Additionally, this research offers new insights and methods for the fields of biomaterials and tissue engineering.