Surface chemistry modulates osteoblasts sensitivity to low fluid shear stress

Area of Science:

• Biomaterials Science
• Cell Biology
• Tissue Engineering

Background:

• Low fluid shear stress (FSS) characterizes the mechanical environment for osteoblasts in native and implanted bone.
• Osteoblast sensitivity to low FSS is vital for promoting osteogenesis (bone formation).
• Scaffold surface chemistry may modulate osteoblast sensitivity to mechanical stimuli.

Purpose of the Study:

• To investigate how varying surface chemistries influence osteoblast sensitivity to low FSS.
• To determine the role of surface chemistry in regulating osteoblast response to mechanical stress for bone regeneration.

Main Methods:

• Fabrication of self-assembled monolayers (SAMs) with distinct surface chemistries (OH, CH3, NH2).
• Application of low FSS (5 dynes/cm²) using a parallel-plate fluid flow system.
• Assessment of osteoblast responses including S-phase fraction, alkaline phosphatase activity, fibronectin (Fn), and collagen type I (COL I) secretion.

Main Results:

• Osteoblasts on OH and CH3 SAMs exhibited significant sensitivity to low FSS.
• Osteoblasts on NH2 SAMs displayed negligible sensitivity to low FSS, attributed to enhanced cell spreading and focal adhesions.
• Despite higher sensitivity on OH and CH3 SAMs, Fn and COL I deposition was lower compared to NH2 SAMs without FSS.

Conclusions:

• Surface chemistry critically regulates osteoblast sensitivity to low FSS.
• Optimizing surface chemistry in conjunction with mechanical stimuli is essential for enhancing both sensitivity and matrix secretion.
• This approach holds promise for developing functional bone tissue in bone regeneration applications.