Surface functionalized electrospun fibrous poly(3-hydroxybutyrate) membranes and sleeves: a novel approach for fixation in anterior cruciate ligament reconstruction

Effective osteointegration for fixation of the tendon to bone junction is the most important issue in anterior cruciate ligament (ACL) reconstruction. In this study, functionalized electrospun poly(3-hydroxybutyrate) (PHB) membranes and sleeves were prepared and evaluated for the fixation of the tendon to bone junction. The electrospun fibrous PHB membranes were modified with hydrogen peroxide, dopamine (DA), chitosan (CS), glutaraldehyde (GA), and then immobilized with growth factors (GFs) from platelet rich plasma (PRP). The water-contact angle measurement showed enhanced wettability in the membranes after the sequential surface functionalization. Successful graftings of DA, CS and GFs from PRP on the membrane surface were demonstrated using X-ray photoelectron spectroscopy (XPS). The ninhydrin assay revealed the amount of immobilized TGF-β1 and PDFG-AB. The modified membranes showed good biocompatibility in an in vitro rabbit tenocyte cultivation study, as the cells showed good attachment and proliferation activity. Significant increases in extracellular matrix and gene expression of type I collagen were observed when the membrane surface was treated with the GFs from PRP. In a rabbit model, the tendon to bone junction was filled with newly formed fibrocartilage and osteointegration behavior was observed. This suggests that the use of functionalized PHB sleeves can enhance tendon to bone healing and the tendon sleeves might provide a novel method for ACL reconstruction.