Electrospining Machine: Preparation of antimicrobial and osteogenic bifunctional micro- and nanocomposite scaffolds by melt electrolysis and solution electrostatic spinning for bone tissue engineering

Background

Repair and treatment of bone defects remains challenging. Traditional methods of bone tissue repair include autologous bone grafting, allogeneic bone grafting, and bone cement filling, but each method has its shortcomings. Currently, with the development of tissue engineering technology, tissue-engineered scaffolds with good biocompatibility, low cytotoxicity, and high osteoinductive ability are increasingly used in bone repair research.

The main point of this paper

MEW Technology Advantage:

Melt Electro-Writing (MEW) is an emerging 3D printing technology capable of accurately depositing fibers with pre-determined patterns to produce highly ordered micron-scale scaffolds

Similarities between MEW and extracellular matrix:

Scaffolds made by MEW have smaller fiber diameters, greater porosity, and are closer to the size of the extracellular matrix (ECM), which is beneficial for cell growth and tissue engineering

Mechanical properties of MEW scaffolds:

MEW scaffolds exhibit better mechanical properties compared to traditional extrusion 3D printing technology, providing stronger mechanical support for bone defect areas

Application of MEW scaffolds in bone tissue engineering:

MEW scaffolds have been widely used to fabricate tissue engineering scaffolds, especially in the simulation of bone-ligament interfaces, showing excellent osteoinductive ability

Development of micro-nanocomposite scaffolds:

MEW microfiber scaffolds were combined with solution electrospinning (SES) nanofibers in the study to provide mechanical support and a microenvironment conducive to cell growth, overcoming the limitations of single materials

Hydroxyapatite (HAP) applications:

Hydroxyapatite (HAP), the main inorganic component of human bone, is widely used for bone repair due to its bioactivity, degradability and osteoconductivity

Application of antibiotics in bone tissue engineering:

Roxithromycin (ROX), a macrolide antibiotic, is used in the prevention and treatment of bone infections, especially in bone infections caused by Staphylococcus aureus.

Micro- and nanocomposite scaffolds: fusion of MEW and SES technologies for bioactive bone repair materials

Combination of techniques:

This study presents a new method combining melt electrophoresis (MEW) and solution electrospinning (SES) techniques for the fabrication of composite scaffolds containing hydroxyapatite (HAP) and rotenone (ROX).

Scaffold structure and composition validation:

The hierarchical structure of nanofiber-microgrids within the scaffolds and the successful loading of HAP and ROX were confirmed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR).

Role of HAP:

The incorporation of HAP enhanced the water absorption capacity of the composite scaffold and promoted cell adhesion, proliferation, and osteogenic differentiation.

Antimicrobial effect of ROX:

ROX showed effective antimicrobial ability and no significant cytotoxicity.

In vivo model application:

Applying the scaffolds to the rat fibula defect model, the 20% HAP group showed better new bone formation and did not cause adverse effects.

Summarize

In this study, a micro-nano composite antibiotic-osteogenic bone tissue engineering scaffold composed of ROX-coated MEW microfiber mesh and HAP-loaded SES nanofibers was successfully prepared. The microfiber mesh loaded with rox has mechanical strength and antibacterial activity, while the nanofiber loaded with hap can simulate ECM and promote the adhesion, proliferation and osteogenic differentiation of osteoblasts. The water absorption test showed that HAP increased the hydrophilicity of the composite scaffold. ROX in the composite scaffold exhibits initial explosive release and subsequent prolonged release behavior. In addition, the composite scaffolds showed obvious antibacterial activity in antibacterial experiments, especially against Gram-positive bacteria. The composite scaffold has also been shown to have good cytocompatibility, and the addition of HAP can further promote the adhesion and proliferation of osteoblasts. ALP activity, ARS staining and RT-qPCR showed that the composite scaffold significantly promoted bone formation, and 20% HAP was the best. Finally, in vivo bone repair experiment showed that 20% HAP group significantly improved the level of skull defect repair without adverse reactions. Therefore, the dual-function micro-nano composite scaffolds prepared by MEW and SES have considerable potential for bone tissue engineering applications.