Gold nanocone array for regulating neuronal behavior

(Nanowerk News) Researchers from Forschungszentrum J├╝lich have reported the enhanced neurite outgrowth of rat primary cortical neurons on the periodic gold nanocone arrays created on the soft and flexible Teflon films.
Reporting their findings in Small ("Flexible Gold Nanocone Array Surfaces as a Tool for Regulating Neuronal Behavior"), the authors present the flexible gold nanocone arrays as a supporting substrate for culture of neuronal cells with excellent cell viability and possibility for regulating cell activity.
The team fabricated their nanostructures by a simple and inexpensive method based on colloidal lithography and oxygen plasma etching. In this method, the nanostructures can be created over centimeter-scale with the geometrically control including height and periodicity by the size of polystyrene (PS) beads from 0.2 up to 2 µm and the etching time.
The nanostructured surfaces are functionalized by a gold thin film enabling the easy surface chemical modification, as well as making the substrate conductive and optically active.
Schematic drawings of the fabrication process of the gold nanocone arrays based on colloidal lithography
a) Schematic drawings of the fabrication process of the gold nanocone arrays based on colloidal lithography. b) Representative SEM images of the gold nanocone arrays created with 0.2, 0.35, 0.5, 1.0, and 2.0 µm PS beads. The scale bars in the insets indicate 200 nm. c) Illustration of gold nanocone arrays. (© Wiley-VCH Verlag)
The scientists report that rat cortical neurons cultured on the gold nanocone surfaces exhibited higher survival rate and accelerated neurite outgrowth compared to that on the planar glass substrate.
Their detailed observation of the cell/nanocone interface suggests that the gold nanocone arrays provide a surface topography which is similar to the structure of filopodia and dendrite with reasonable contacting area for cell attachment, in addition to the periodicity of the structure to induce the mechanical tension to the neurite, which may be the key factors of the scaffold for the acceleration of the neurite outgrowth.
The autjors conclude that the presented nanocone array substrates may hold great potentials for the new design of the neuronal interface with 3D nanostructures by following three aspects which are important for the device applications.
First, the structures can be created by a simple and cheap fabrication process without using clean room facility, and the geometry of nanocone including the pitch and the height is easily controllable.
Secondary, the Teflon films used as the substrate are flexible and holding antifouling properties, it can be used for enhancing the adhesion of neuronal cells and formation of their networks in the selected area on the device.
Finally, the deposition of gold films allows the substrate to be conductive and to hold unique optical properties supported by surface plasmons, which are crucial for electrophysiological and optical measurements as well as inducing the electric or optical stimuli to the attached cells.
Michael Berger By – Michael is author of three books by the Royal Society of Chemistry:
Nano-Society: Pushing the Boundaries of Technology,
Nanotechnology: The Future is Tiny, and
Nanoengineering: The Skills and Tools Making Technology Invisible
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