Cost effective optimised synthetic surface modification strategies for enhanced control of neuronal cell differentiation and supporting neuronal and Schwann cell viability.

Caroline S Taylor,John A Hunt,Judith M Curran,Rui Chen,Raechelle D' Sa,John W Haycock

doi:10.1002/jbm.b.34829

Abstract

Enriching a biomaterial surface with specific chemical groups has previously been considered for producing surfaces that influence cell response. Silane layer deposition has previously been shown to control mesenchymal stem cell adhesion and differentiation. However, it has not been used to investigate neuronal or Schwann cell responses in vitro to date. We report on the deposition of aminosilane groups for peripheral neurons and Schwann cells studying two chain lengths: (a) 3-aminopropyl triethoxysilane (short chain-SC) and (b) 11-aminoundecyltriethoxysilane (long chain-LC) by coating glass substrates. Surfaces were characterised by water contact angle, AFM and XPS. LC-NH2 was produced reproducibly as a homogenous surface with controlled nanotopography. Primary neuron and NG108-15 neuronal cell differentiation and primary Schwann cell responses were investigated in vitro by S100β, p75, and GFAP antigen expression. Both amine silane surface supported neuronal and Schwann cell growth; however, neuronal differentiation was greater on LC aminosilanes versus SC. Thus, we report that silane surfaces with an optimal chain length may have potential in peripheral nerve repair for the modification and improvement of nerve guidance devices.

Highlights

Peripheral nerve injuries affect 7 million people globally every year, and most commonly arise from trauma incidents.[1]
Previous studies have demonstrated that changing the chain length of silane changes the surface topography of a substrate, via deposition of amine groups, controlling initial cell adhesion and influencing cellular differentiation.[9]
Silane chain length has been previously shown to control osteo-induced differentiation of mesenchymal stem cells, and a similar effect was hypothesized for neuronal cell differentiation.[10]

Summary

| INTRODUCTION

Peripheral nerve injuries affect 7 million people globally every year, and most commonly arise from trauma incidents.[1]. Synthetic coatings can control the type, level and conformation of serum proteins that adsorb.[1] Alteration of the surface chemistry can influence protein surface conformation, and influence initial adhesion, proliferation and cell differentiation.[5] Techniques such as plasma polymerization have been used to alter biomaterial surface chemistry, without altering bulk material properties.[1] Plasma deposition studies report on acrylic acid and allyamine surface modification improving SH-SY5Y neuronal cell adhesion and differentiation[6] and air plasma techniques increasing primary Schwann cell adhesion onto modified surfaces, increasing nerve regenerative properties of conduits when grafted with peptide or growth factors.[7] plasma polymerization requires a high vacuum, limiting scale-up,[8] supporting a need for simpler surface modification. The aim of the present study was to investigate the influence of two different silane chain lengths, with known surface chemistry and topography, characterised from our previous study,[10] on neuronal and Schwann cell differentiation and phenotype

| MATERIALS AND METHODS

| RESULTS

| DISCUSSION