Instructive electroactive electrospun silk fibroin-based biomaterials for peripheral nerve tissue engineering.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Neuroscience

Background:

• Aligned sub-micron fibers are ideal for orienting and promoting neurite outgrowth, making them attractive for peripheral nerve tissue scaffolds.
• Current peripheral nerve tissue scaffold development incorporates electroactive materials and electrical stimulation for enhanced functional regeneration.

Purpose of the Study:

• To develop novel electroactive fibers composed of silk fibroin (SF) and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) for peripheral nerve tissue scaffolds.
• To investigate the influence of PEDOT:PSS incorporation on the mechanical, electrical, and biocompatibility properties of SF scaffolds for nerve regeneration.

Main Methods:

• Fabrication of SF mats with sub-micron fiber diameters using double layer electrospinning, followed by modification with interpenetrating polymer networks (IPN) of PEDOT:PSS.
• Characterization of mechanical properties (wet state tensile), electrical properties (cyclic voltammetry, electrochemical impedance spectroscopy), and polymerization (HAXPES).
• Assessment of cytotoxicity and biocompatibility using mouse neuroblastoma x rat glioma hybrid cells (NG108-15), measuring cell growth and neurite extension.

Main Results:

• Optimal IPNs (α = 2.3 and 3.3) demonstrated good biocompatibility and supported cell growth.
• The longest neurite outgrowth (300 μm) was observed on laminin-coated SF and IPN (α = 2.3) mats, parallel to fiber alignment.
• The most effective material (IPN, α = 2.3) exhibited the lowest electron transfer resistance (ca. 330 Ω).

Conclusions:

• Electrically conductive composite fibers with aligned sub-micron structures show significant promise for axon guidance in peripheral nerve regeneration.
• These novel scaffolds have the potential to be combined with electrical stimulation for advanced nerve repair strategies.