Development of a bioreactor for evaluating novel nerve conduits

Area of Science:

• Biomedical Engineering
• Tissue Engineering
• Regenerative Medicine

Background:

• Peripheral nerve injuries often require nerve conduits for repair.
• Evaluating novel conduit materials and culture conditions in vitro is essential before in vivo studies.
• Existing methods may not adequately mimic physiological flow conditions for cell seeding and growth.

Purpose of the Study:

• To develop and validate an experimental closed bioreactor system for in vitro assessment of tissue-engineered peripheral nerve conduits.
• To investigate the effects of static versus continuous flow culture conditions on Schwann cell distribution and viability within various nerve conduit scaffolds.
• To evaluate the impact of scaffold surface modifications on cell adhesion and proliferation.

Main Methods:

• A closed-loop bioreactor system was designed to accommodate one to three nerve conduits (10-80 mm length) in series or parallel.
• Aligned synthetic microfiber scaffolds (viscose rayon, electrospun polystyrene) were used.
• Schwann cells were seeded and cultured under static or continuous flow (0.8 mL/h) conditions for 4 days.
• In situ viability measurements and fluorescence microscopy were employed to assess cell distribution, viability, adhesion, and alignment.

Main Results:

• Static culture resulted in limited viable cell distribution, primarily in shorter conduits or at conduit ends.
• Continuous medium flow (0.8 mL/h) increased total cell number by 2.5-fold and parallel viability by ninefold compared to static culture.
• Surface modification with type-1 collagen or acrylic acid enhanced cell numbers by 17% and 30%, respectively.
• Fluorescence microscopy confirmed cellular adhesion and alignment along the scaffold's longitudinal axis.

Conclusions:

• The developed bioreactor system provides a rigorous and controlled environment for evaluating novel peripheral nerve conduits in vitro.
• Continuous flow culture significantly promotes Schwann cell viability and proliferation within nerve conduits, outperforming static conditions.
• This system facilitates the assessment of scaffold properties and cell behavior, paving the way for improved peripheral nerve repair strategies using hydrolysable materials.