Immobilized nerve growth factor and microtopography have distinct effects on polarization versus axon elongation in hippocampal cells in culture

Micropatterned Polypyrrole: A Combination of Electrical and Topographical Characteristics for the Stimulation of Cells

“…[18] Here, we corroborated and confirmed these results by fabricating similar topographical features on a conducting polymer. As observed in Figure 7, hippocampal neurons cultured on PPy microchannels polarized faster, meaning that more cells had defined axons compared to controls on unmodified PPy.…”

“…Figure 8B shows that PPy microtopography did not result in a significant increase in axon length from hippocampal cells compared to cells cultured on unmodified PPy (P = 0.13 for 2 µm microchannels; P = 0.92 for 1 µm microchannels). We previously found this same trend on PDMS microchannels, [18] as illustrated in Figure 8B. These results suggest that surface topographical features have a more dramatic effect on axon-initiation mechanisms (i.e., polarization), but these effects become negligible once the axon is established and undergoes elongation.…”

“…In contrast, we previously reported that ligands such as NGF have a stronger effect on axon elongation than topography. [18] This trend suggests that physical guidance provided by PPy microchannels could be combined with chemical cues such as immobilized NGF to further optimize axon outgrowth.…”

“…In a different study, poly(dimethyl siloxane) (PDMS) microchannels modified with immobilized NGF effectively increased neuronal polarization (i.e., axon formation) and the axon length of neurons. [18] Combination of physical cues (i.e., microchannels) and chemical guidance (i.e., immobilized protein) was essential for favorable neuronal responses. Based on these results, we hypothesize that a conducting polymer with both physical-and chemical-guidance cues could further improve axon formation and growth.…”

Nanotechnology in regenerative medicine: the materials side

“…Microtopography influences cell adhesion, proliferation and differentiation [1,2] and, more recently, it has become clear that nanotopography also guides cell behaviour greatly [3,4]. In some applications, in which guiding the cell orientation is essential to achieve a functional tissue, such as for tendons, nerves, corneal stroma and intervertebral-disc regeneration, contact guidance of cells by micro-and nano-topographical patterns is a promising perspective [5,6]. Chemical cues in the form of various different biomolecules (nanometre scale), such as adhesive protein or growth factors, also influence cell behaviour crucially.…”