Chemically Functionalized Silk for Human Bone Marrow-Derived Mesenchymal Stem Cells Proliferation and Differentiation

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Materials Chemistry

Background:

• Silk fibroin (SF) is a promising biomaterial for tissue engineering.
• Enhancing SF's mechanical properties and biocompatibility is crucial for bone regeneration applications.
• Introducing functional groups can improve SF's interaction with cells and mineralization.

Purpose of the Study:

• To develop mechanically robust and biocompatible silk-based materials for bone tissue engineering.
• To functionalize silk fibroin with carboxyl groups using chemical oxidation.
• To evaluate the impact of oxidation on the structural, mechanical, and cellular properties of silk scaffolds.

Main Methods:

• Chemical oxidation of silk fibroin using sodium hypochlorite (NaClO) to introduce carboxyl groups.
• Characterization of oxidized silk (OxSF) using infrared (IR) spectroscopy and circular dichroism (CD) spectroscopy.
• Fabrication and mechanical testing (compressive modulus) of SF, OxSF, and mineralized OxSF (M-OxSF) scaffolds.
• In vitro culture of human bone marrow-derived mesenchymal stem cells (hMSCs) on scaffolds to assess proliferation and osteogenic differentiation.

Main Results:

• Oxidation introduced carboxyl groups onto SF, achieving a content of 1.09 mM/g.
• Oxidized silk (OxSF) self-assembled into β-sheet structures, enhancing mechanical properties.
• OxSF scaffolds showed a 10-fold increase in compressive modulus (211 ± 75 KPa) compared to SF scaffolds.
• Mineralized OxSF (M-OxSF) scaffolds exhibited further increased modulus (758 ± 189 KPa).
• OxSF scaffolds supported hMSC proliferation and osteogenic differentiation in vitro.

Conclusions:

• Chemical oxidation is an effective method to produce biocompatible and mechanically robust silk fibroin materials.
• The resulting OxSF scaffolds possess enhanced structural integrity and mechanical strength suitable for bone tissue engineering.
• OxSF scaffolds promote the proliferation and differentiation of human mesenchymal stem cells, indicating potential for bone regeneration therapies.