Surface-Functionalized Electrospun Polycaprolactone/Fibrinogen Scaffold for Delivering Platelet-derived Growth Factor

Objectives: Traditional wound dressings act as a physical barrier to prevent infection and help control hemostasis. However, most dressings do not enhance the healing process. Platelet-derived growth factor (PDGF) plays an integral role in all aspects of the wound healing process. Previously, we have shown that exogenous PDGF administration augments cell infiltration, migration, and proliferation. The objective of the current work is to expand the effectiveness of the PDGF delivering polycaprolactone (PCL)/fibrinogen (Fb) scaffold for maxillofacial soft tissue regeneration after trauma by covalently attaching PDGF through heparin groups and post-fabrication crosslinking. The main objective is that the inclusion of functionalized PCL with Fb should significantly increase the mechanical stability of the scaffold, stabilize PDGF for long-term storage, and improve PDGF release kinetics.
Methods: Polycaprolactone/Fb scaffolds were electrospun, and subsequent stabilization of PDGF to PCL was performed using 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (sulfo-NHS). Resulting scaffolds were characterized chemically and physically using fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and helium pycnometry to study internal composition, topography, and porosity, respectively. Additionally, the extent of functionalization was assessed through fluorescent microscopy, a toluidine blue (TB) heparin binding assay, and confocal microscopy.
Results: Preliminary TB assay demonstrated increases in heparin activity on the surface of the scaffolds, after reactive groups were introduced, indicating control over the functionalization process. This observation was supported by FTIR, which shows both amide I bands and hydroxyl stretching peaks in modified scaffolds that are not expressed in unmodified controls. Furthermore, results did not suggest any residual solvent or negative effects from the electrospinning process.
Conclusions: The study herein demonstrates the viability of heparinization as a means of improving PDGF stability. Future studies will investigate cellular function over 7 days, as well PDGF bioactivity after 90 days of storage.