Neuroprosthetic technologies for therapeutic neuromodulation have seen major advances in recent years but these advances have been impeded due to electrode failure or a temporal deterioration in the device recording or electrical stimulation potential. This deterioration is attributed to an intrinsic host tissue response, namely glial scarring or gliosis, which prevents the injured neurons from sprouting, drives neurite processes away from the neuroelectrode and increases signal impedance by increasing the distance between the electrode and its target neurons. To address this problem, there is a clinical need to reduce tissue encapsulation of the electrodes in situ and improve long-term neuroelectrode function. Nanotopographical modification has emerged as a potent methodology for the disruption of protein adsorption and cellular adhesion in vitro. This study investigates the use of block copolymer self-assembly technique for the generation of sub-20 nm nanowire features on silicon substrates. Critically, these nanostructures were observed to significantly reduce electrical impedance and increase conductivity. Human neuroblastoma SH-SY5Y cells cultured on nanowire substrates for up to 14 days were associated with enhanced focal adhesion reinforcement and a reduction in proliferation. We conclude that nanowire surface modulation may offer significant potential as an electrode functionalization strategy.
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The authors would like to acknowledge (AMBER) Advanced Materials and BioEngineering Research and (SFI) Science Foundation Ireland for funding through SFI-AMBER (Grant No. SFI 12/RC/2278 AMBER). We acknowledge the joint funding received from Irish Research Council through IRC New Foundation Scheme/Nano Surface project. Also the authors thank Advance Microscopy Laboratory (AML)/CRANN for their collaboration and facilities. Bell Labs Ireland thanks the Industrial Development Agency (IDA) Ireland for their financial support. M. J. Biggs is a Science Foundation Ireland, Starting Investigator SIRG COFUND fellow, Grant No. 11/SIRG/B2135.
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Mokarian-Tabari, P., Vallejo-Giraldo, C., Fernandez-Yague, M. et al. Nanoscale neuroelectrode modification via sub-20 nm silicon nanowires through self-assembly of block copolymers. J Mater Sci: Mater Med 26, 120 (2015). https://doi.org/10.1007/s10856-015-5426-2
- Block Copolymer
- Iron Nitride
- Spin Cast
- Solvent Vapor Annealing