Impact of conduit-filling interactions on the efficacy of fiber and hydrogel fillers in nerve conduits

Flavia Millesi; Sascha Mero; Sebastian Rihl; Sophie Steinwenter; Sarah Stadlmayr; Anton Borger; Paul Supper; Maximilian Haertinger; Leon Ploszczanski; Gerhard Sinn; Aida Naghilou; Lorenz Semmler; Christine Radtke

doi:10.1016/j.isci.2025.113150

Impact of conduit-filling interactions on the efficacy of fiber and hydrogel fillers in nerve conduits

iScience. 2025 Jul 18;28(8):113150. doi: 10.1016/j.isci.2025.113150. eCollection 2025 Aug 15.

Authors

Flavia Millesi^{1

2}, Sascha Mero^{1

2

3}, Sebastian Rihl¹, Sophie Steinwenter¹, Sarah Stadlmayr^{1

2}, Anton Borger^{1

2

4}, Paul Supper^{1

2

4}, Maximilian Haertinger^{1

2}, Leon Ploszczanski⁵, Gerhard Sinn⁵, Aida Naghilou^{1

2

6}, Lorenz Semmler^{1

2

4}, Christine Radtke^{1

2

4}

Affiliations

¹ Research Laboratory of the Department for Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Spitalgasse 23, 1090 Vienna, Vienna, Austria.
² Austrian Cluster for Tissue Regeneration, Vienna, Vienna, Austria.
³ Department of Urology, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, , Vienna, Austria.
⁴ Department for Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Vienna, Austria.
⁵ Institute for Physics and Materials Science, University of Natural Resources and Life Sciences, Peter-Jordan-Straße 82, 1190 Vienna, Vienna, Austria.
⁶ Department of Physical Chemistry, University of Vienna, Währingerstraße 42, 1090 Vienna, Vienna, Austria.

Abstract

Nerve conduits offer an alternative to autologous nerve grafts, yet their clinical application remains restricted to short injuries with unsatisfactory outcomes. This study aimed to elucidate the factors responsible for these poor results. We systematically compared three commercially available conduits, assessing their impact on Schwann cells and fibroblasts in vitro alongside their material properties. Additionally, we evaluated the impact of luminal fillings -spider silk, hydrogel, and their combination- on cell behavior. All three hollow nerve conduits inhibited cell attachment, proliferation, and migration. Fillings significantly improved cellular responses, with effects varying depending on conduit type and material. Notably, spider silk and hydrogel influenced each other's efficacy. Our experiments highlight the limitations of empty nerve conduits and served as a mechanistic exploration to unravel the reasons behind the superior outcomes observed with filled nerve conduits, underscoring the imperative for advancements in conduit design.

Keywords: Biomaterials; Materials science; Neuroscience.