Immuno-Informed 3D Silk Biomaterials for Tailoring Biological Responses

Area of Science:

• Biomaterials Science
• Immunology
• Tissue Engineering

Background:

• Macrophages are crucial for immunoregulation, tissue repair, and vascularization.
• Immuno-informed biomaterials are vital for regulating the microenvironment of biomedical implants.
• Silk-based hydrogels offer a promising platform for controlling immune cell behavior.

Purpose of the Study:

• To investigate the use of silk-based 3D hydrogels for regulating cytokine delivery and macrophage polarization.
• To evaluate different silk hydrogel variants (SP, SH, SS) for controlled release of polarizing cytokines.
• To assess the potential of these hydrogels as immuno-informed biomaterials.

Main Methods:

• Fabrication of three silk-based hydrogel variants (SP, SH, SS).
• Loading hydrogels with M1 (interferon-γ) and M2 (interleukin-4) polarizing cytokines.
• Investigating macrophage polarization using gene expression analysis (CCR7, IL-1β, CD206, CD209) under various cytokine exposure and macrophage encapsulation conditions.

Main Results:

• Silk hydrogels successfully released cytokines, inducing macrophage polarization from M0 to M1/M2 phenotypes.
• Demonstrated plasticity of macrophages, allowing switching between M1 and M2 phenotypes.
• Macrophage encapsulation within hydrogels, with or without cytokines, effectively induced M1 or M2 polarization.

Conclusions:

• Silk hydrogels serve as a novel system for the focal delivery of cytokines and macrophages.
• These silk-based biomaterials can be considered "immuno-informed" for controlling immune responses.
• The study highlights the potential of silk hydrogels in regenerative medicine and tissue engineering applications.