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Introduction

The focus of this study is on the advancement of three-dimensional (3D) scaffolds for tissue engineering, specifically using a polymethyl methacrylate (PMMA) scaffold processed through a CO2 laser drilling technique. Scaffolds are critical in tissue engineering as they replicate the extracellular matrix (ECM) and facilitate cell attachment, proliferation, and tissue formation. Compared to traditional methods such as autografts and allografts, which are limited by volume and potential complications, 3D scaffolds can be engineered to possess desired characteristics, including interconnected pore networks essential for biological functions.

Key Features of Ideal Scaffolds

For effective tissue regeneration, scaffolds must exhibit:

  • Interconnected Pores: This enables cell migration, differentiation, and attachment throughout the scaffold.

  • Nutrient Channels: Channels facilitating oxygen and nutrient supply while removing waste products are essential.

  • Biocompatibility and Bioactivity: Scaffolds should attract cells and support proliferation.

  • Mechanical Compatibility: Strength properties should align with surrounding bone characteristics.

  • Controlled Design: The ability to control porosity and pore geometry is vital for functionality.

Methods of Scaffold Fabrication

There are various methods for scaffold fabrication including solvent casting, fiber bonding, and gas-induced foaming. However, these methods often yield random architectures. Solid Freeform Fabrication (SFF) techniques, such as selective laser melting, allow for anatomically shaped scaffolds but come with limitations regarding material properties and production speed.

Laser Drilling Technique

The study employs CO2 laser drilling to create PMMA scaffolds with high porosity and precise interconnectivity.

  • Laser Parameters

    • Power: 100 W, controlling the amount of energy applied to the PMMA.

    • Focus and Movement: The laser focus and CNC table movement ensure precise drilling patterns, allowing for customization of the scaffold’s internal architecture.

Materials Used

PMMA

PMMA is a polymer with significant biocompatibility, making it suitable for use in bone repair. However, it is non-degradable, which necessitates the enhancement of its bioactivity through coatings.

Chitosan/B-TCP Composite Coating

To improve PMMA's properties, a chitosan/B-TCP (Beta-tricalcium phosphate) composite is used, known for its biocompatibility and support in bone regeneration. This composite coating enhances cell proliferation, providing a biologically favorable environment for osteoblasts.

Experimental Setup

  • Preparation of Composite: Chitosan is dissolved in acetic acid, followed by the addition of B-TCP particles. This mixture is combined to form a homogeneous coating solution.

  • Coating Process: Prepared PMMA scaffolds are dipped into the composite solution, ensuring uniform cover on both surfaces and enhancing interaction with osteoblast-like cells.

Results and Discussion

Porosity and Compressive Strength

Three scaffold designs were created, each varying in porosity levels. A clear relationship exists between the porosity of the scaffolds and their compressive strength:

  • Higher porosity correlates with lower compressive strength, indicating a trade-off between structural integrity and the scaffold's ability to support cellular activity.

Cell Proliferation Study

The proliferation of SaOS-2 osteoblast-like cells was assessed on various scaffold types, demonstrating that scaffolds with the chitosan/B-TCP composite coating exhibited superior cell attachment and growth compared to bulk and porous PMMA scaffolds.

Conclusion

The laser drilling technique presented in this study successfully creates PMMA scaffolds with effective properties for bone regeneration applications. The incorporation of chitosan/B-TCP coating significantly enhances the bioactivity and suitability of the PMMA scaffolds for use in tissue engineering, supporting our hypothesis of their potential in clinical settings.