Processing/Characterization of an Electrospun Composite Nano/Microfibrous Scaffold for Endodontic Regeneration

A proper scaffold is crucial for successful endodontic regenerative treatment of the infected immature permanent tooth. Currently, the blood clot induced into the disinfected pulp space acts as a fibrin-based scaffold aiding in the root lengthening and maturogenesis. Unfortunately, treatment outcomes may vary owing to the inherent differences of the fibrin clot such as unknown cell types and angiogenesis.

Objective: To (1) fabricate a synthetic polydioxanone (PDSII^®) electrospun fibrous composite scaffold incorporated with aluminosilicate nanotubes and (2) investigate the effects of nanotube incorporation on the mechanical properties. The rationale for electrospun composite fabrication is to allow further biologically-active molecules (i.e., growth factors/antibiotics) encapsulation inside the hollowed nanotube structure to create an environment conducive to root maturogenesis.

Method: FDA-approved PDSII^® was dissolved in HFP (Sigma). Aluminosilicate nanotubes (Applied Minerals) were incorporated at (1-10wt.%, relative to PDS w/w) in the PDS solution following a dispersion/homogenization procedure for further electrospinning. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and tensile testing were used to characterize the structure, morphology, and mechanical properties of the scaffolds (G1-control, G2-1wt.%, G3-3wt.%, G4-5wt.% and G5-10wt.%). Data were subjected to one-way ANOVA (α=0.05).

Result: SEM analysis of the scaffolds revealed an overall submicron fibrous morphology and interconnected pore network. FTIR confirmed the presence of characteristics peaks for PDS and aluminosilicate nanotubes. Mechanical properties and fiber diameter (mean±SD) are given below.

Groups	Tensile Strength(MPa)	Tensile Modulus(MPa)	Strain(%)	Diameter(nm)
G1-control	6.32±1.2A	15.27±8.93A	123±98A	1132±381A
G2-1wt.%	3.03±1.06B	4.09±1.11B,D	194±70B	1388±421B
G3-3wt.%	3.38±0.28B,C	2.45±0.63C	290±43C	1022±336A,D
G4-5wt.%	3.18±0.20C	3.51±0.84B	213±37B	1071±352A,D
G5-10wt.%	1.32±0.24D	4.07±1.02B,D	129±47A	1657±575C

^{Same letters within the column indicate non-statistically significant differences(p>0.05).}

Conclusion: An electrospun composite fibrous material holds promise as a scaffold as well as a drug-delivery device to aid in root maturogenesis. Optimization of the composite physical-mechanical properties and evaluation of cytocompatibility/proliferation issues are currently being pursued.