Radiopaque polycaprolactone/barium sulfate nanofibers for applications in soft tissue repair

Purpose: Monitoring performance of material inside the human body is still an open problem. X-ray imaging is an easy and noninvasive method of visualization, however, many biomaterials, such as polymers are radiolucent. Potential solution of this problem is to combine selected polymer with a compound which can act as a marker. Thus, this study aimed to obtain radiopaque polymeric fibers of polycaprolactone (PCL) by electrospinning.

Methods: As radiopaque marker barium sulfate (BaSO₄) powder was used. The obtained composite nonwovens were subjected to physicochemical properties (wettability, surface free energy), mechanical (uniaxial tensile test), stability in acidic environment and biocompatibility tests.

Results: Barium sulfate (diameter of 0.03–1.3 μm for non-grinded, 0.8–90 μm for grinded) was encapsulated inside the PCL fibers (average diameter 0.91 μm), proved by scanning electron microscopy observations and energy-dispersive X-ray spectroscopy. Addition of barium sulfate to the fibers in caused them to become thicker and changed diameter distribution from bimodal to unimodal. All materials were hydrophobic, with contact angle for water over 120° with no statistically significant difference and their surface free energy consisted mainly of disperse component (around 1:10 P/D ratio). Mechanical properties such as the maximum tensile force and tensile strength decreased by 50–60% after addition of barium sulfate. After three and seven days of cell culture with BJ fibroblasts, obtained materials proved to be biocompatible.

Conclusions: The results presented in this work allow to state that fibrous composite material composed of PCL and barium sulfate has potential as biomaterial that can be visualized and monitored after implantation using RTG imaging.