Flexible bipolar nanofibrous membranes for improving gradient microstructure in tendon-to-bone healing

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Orthopedic Surgery

Background:

• Enthesis, the tendon-bone interface, has a complex gradient structure.
• Current strategies struggle to regenerate this specialized tissue due to its complexity.
• Rotator cuff tears often involve damage to the enthesis, impairing healing.

Purpose of the Study:

• To develop a biomimetic dual-layer fibrous membrane for enthesis regeneration.
• To mimic the non-mineralized and mineralized fibrocartilage layers of the enthesis.
• To enhance tendon-to-bone integration and healing in rotator cuff repair.

Main Methods:

• Fabrication of a flexible bipolar fibrous membrane (BFM) using electrospinning.
• Sequential electrospinning of poly-l-lactic acid (PLLA) and nano hydroxyapatite-poly-l-lactic acid (nHA-PLLA) layers.
• In situ induction of apatite nanoparticle layer on the nHA-PLLA layer.

Main Results:

• BFM successfully mimicked non-mineralized and mineralized fibrocartilage.
• In vivo studies showed increased glycosaminoglycan, improved collagen organization, and enhanced bone formation.
• Biomechanical testing revealed greater ultimate load-to-failure and stiffness in the BFM group compared to controls.

Conclusions:

• The developed flexible bipolar nanofibrous membrane significantly improves enthesis healing and regeneration.
• BFM provides a promising strategy for rotator cuff repair by enhancing tendon-bone integration.
• This biomimetic approach offers a gradient microstructure for effective enthesis regeneration.