ROS scavenging nanoengineered bioactive glass interfaces reprogram macrophage immunity for tendon-bone regeneration

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Immunology

Background:

• Rotator cuff repair often fails due to poor tendon-bone interface (TBI) regeneration, driven by inflammation and reactive oxygen species (ROS).
• Current biomaterials lack effective immunomodulatory and antioxidant properties for optimal TBI healing.

Purpose of the Study:

• To engineer an immunoregulatory suture interface using cerium-doped mesoporous bioactive glass nanoparticles (Ce-MBGNs).
• To evaluate the capacity of Ce-MBGN-functionalized sutures to promote TBI regeneration by modulating inflammation and ROS.

Main Methods:

• Developed a gelatin/tannic acid (Gel/TA) coating incorporating Ce-MBGNs onto polyethylene terephthalate sutures.
• Assessed coating properties, ROS scavenging, and effects on bone marrow mesenchymal stem cells (BMSCs) and macrophages *in vitro*.
• Evaluated suture performance in a rat rotator cuff repair model, analyzing TBI regeneration, bone mineral density, and immune cell infiltration *in vivo*.

Main Results:

• The Gel/TA/Ce-MBGN coating exhibited uniform morphology, strong adhesion, and superior ROS scavenging.
• *In vitro* studies showed enhanced osteogenic/chondrogenic differentiation of BMSCs and M2 macrophage polarization with reduced intracellular ROS.
• *In vivo* results demonstrated improved fibrocartilaginous enthesis regeneration, increased bone mineral density, and elevated M2 macrophage infiltration at the TBI.

Conclusions:

• Ce-MBGN-functionalized sutures effectively scavenge ROS and modulate the immune response, fostering a pro-regenerative microenvironment.
• This strategy promotes multi-lineage tissue regeneration at the TBI, offering a promising approach for improving rotator cuff repair.
• The developed sutures represent a clinically translatable method for immunomodulatory suture design.