Cuttlebone inspired "S"-grooved topological structures facilitate osteogenic differentiation through the Rap1-ERK...

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Cell Biology

Background:

• Biomaterial surface topology influences bone regeneration, but mechanisms driven by morphology alone are unclear.
• Understanding topology-driven osteogenesis is crucial for designing effective bone regeneration scaffolds.
• Cuttlebone's natural structure offers inspiration for biomimetic material design.

Purpose of the Study:

• To investigate the osteogenic potential of a biomimetic "S"-grooved topology.
• To elucidate the cellular and molecular mechanisms underlying topology-driven osteogenesis.
• To fabricate and characterize polycaprolactone (PCL) membranes with cuttlebone-like "S"-grooves.

Main Methods:

• Fabrication of biomimetic PCL membranes using liquid silicone mold replication and PCL recasting.
• Characterization of surface morphology using Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM).
• In vitro assessment of rat bone marrow mesenchymal stem cell (rBMSC) adhesion, proliferation, and osteogenic differentiation of mouse pre-osteoblasts (MC3T3-E1), including ALP activity and mineralization assays.
• Mechanistic studies involving RT-qPCR, Western blot, and quantitative proteomics to analyze the Rap1-ERK signaling pathway.

Main Results:

• Successfully fabricated PCL membranes with precise replication of cuttlebone "S"-grooved topology.
• Demonstrated contact guidance of rBMSCs, promoting directional adhesion and proliferation.
• Significantly enhanced osteogenic differentiation of MC3T3-E1 cells, evidenced by increased ALP activity and mineralized nodule formation.
• Identified upregulation of Rap1 and enhanced ERK phosphorylation in rBMSCs cultured on "S"-grooved surfaces, leading to increased osteogenic marker expression.

Conclusions:

• Biomimetic "S"-grooved topology alone, without biochemical cues, significantly promotes osteogenic differentiation.
• The Rap1-ERK signaling pathway is a key mediator of topology-driven osteogenesis via contact guidance.
• Topologically optimized biomaterials hold promise for enhanced bone regeneration applications.