Monocyte inflammatory and matrix remodeling response modulated by grafted ECM-derived ligand concentration

Area of Science:

• Biomaterials Science
• Immunology
• Tissue Engineering

Background:

• Biomaterial surface modification with ligands is crucial for controlling host responses.
• Extracellular matrix (ECM)-derived peptides are commonly used to enhance biomaterial integration.
• Understanding how peptide concentration affects immune cell interactions is vital for biomaterial design.

Purpose of the Study:

• To investigate the impact of varying extracellular matrix (ECM)-derived peptide concentrations on biomaterial surfaces.
• To examine the effects of these modified surfaces on monocyte adhesion, protein expression, and gene regulation.
• To elucidate the relationship between surface ligand density and immune cell behavior in a semi-interpenetrating network (sIPN) system.

Main Methods:

• Fabrication of gelatin and polyethylene glycol diacrylate (PEGdA) based semi-interpenetrating networks (sIPNs).
• Controlled surface peptide (RGD-PEG) concentration by adjusting the ratio of peptide-PEG grafted gelatin to PEGdA.
• Assessed monocyte adhesion, and quantified protein and mRNA expression of matrix metalloprotease-2 (MMP-2), matrix metalloprotease-9 (MMP-9), and interleukin-1beta (IL-1beta).

Main Results:

• Increased RGD peptide concentration on sIPN surfaces led to higher monocyte adhesion.
• Protein levels of MMP-2 and IL-1beta showed an initial increase at higher ligand concentrations.
• IL-1beta protein and mRNA expression decreased over time, while MMP-2 mRNA was undetectable despite detectable protein levels.

Conclusions:

• Surface ligand concentration significantly modulates monocyte adhesion to biomaterials.
• Ligand density influences the release of key inflammatory and matrix-degrading proteins.
• Biomaterial surface chemistry, specifically ligand identity and concentration, is critical for controlling immune cell responses.