Automated Seamless Poly(ε-Caprolactone) Electrospun Tubes for Critically-Sized Bone Defect Repair

Abstract

In this study, we demonstrate an automated approach to efficiently and reproducibly manufacture perforated poly(ε-caprolactone) (PCL) solution electrospun tubular meshes designed for critically-sized bone defect repair. The workflow improves reproducibility and reduces fabrication time by 67% (8.7 vs. 2.7 h per 10 meshes). By directly electrospinning PCL onto a rotating cylindrical mandrel, seam-related discontinuities are eliminated, and subsequent use of an automated soldering iron system enables precise 1 mm perforations that promote vascular ingrowth during bone healing. Despite the decrease in mass of the new design compared with the original design (18.24 ± 1.5 mg for old vs. 11.48 ± 1.2 mg for new design), mechanical testing revealed similar resistance to lateral compression compared with semimanually assembled meshes. This is important to prevent collapse during surgical placement and injection of osteoinductive treatments. Further, eliminating surgical glue improves the manufacturing simplicity and scaffold reproducibility. Following implantation with bone morphogenic protein-2 loaded alginate, the new design performed similarly to the original: in vivo microcomputed tomography confirmed bone formation that significantly increased (p ≤ 0.05) over 8-weeks in an established rat femoral defect model. This study provides a novel production method of tubular scaffolds with variable dimensions and flexible perforation patterns and demonstrates improvements in fabrication efficiencies and reproducibility.

Impact Statement

Gap defects in femurs can be researched with mesh–hydrogel constructs to guide bone regeneration. We present an automated soldering-iron method that precisely perforates electrospun PCL tubular scaffolds. The process shortens fabrication time, reduces material usage and waste, and maintains compressive resistance comparable to conventional meshes, improving surgical handling and fixation reliability. Beyond this, the approach generalizes to low-cost perforation of polycaprolactone scaffolds and tubular implants, enabling rapid prototyping, standardized training, and adoption in resource-limited settings. Together, these advances support more predictable healing, lower costs, and accelerated translation of mesh-assisted therapies for segmental long-bone injuries clinically worldwide.