In-situ guidance of individual neuronal processes by wet femtosecond-laser processing of self-assembled monolayers

Abstract

guidance of neuronal processes (neurites) is demonstrated by applying wet femtosecond-laser processing to an organosilane self-assembled monolayer (SAM) template. By scanning focused laser beam between cell adhesion sites, on which primary neurons adhered and extended their neurites, we succeeded in guiding the neurites along the laser-scanning line. This guidance was accomplished by multiphoton laser ablation of cytophobic SAM layer and subsequent adsorption of cell adhesion molecule, laminin, onto the ablated region. This technique allows us to arbitrarily design neuronal networks .

Surface Modification of Cell Scaffold in Aqueous Solution Using TiO₂Photocatalysis and Linker Protein L2 for Patterning Primary Neurons<i></i>

“…The laser ablation method, however, suffered from the low success rate of neurite guidance, which was primarily due to the mechanical damage to the neurons induced cavitation bubbles generated at the focal point of the laser and to the unstable adsorption of the scaffolding protein, Ln, to the laser irradiated region [26]. To overcome the first issue, we very recently developed a novel surface modification method that takes advantage of titanium dioxide (TiO 2 ) photocatalysis to decompose non-permissive compounds upon irradiation of ultraviolet (UV) light [27].…”

“…Such "in-situ"or "dynamic" patterning has been realized, for example, by using photoresponsive polymers [23,24] or laser ablation [25,26], just to name a few. We previously reported on the application of laser ablation phenomena to create growth pathways of neuronal processes (neurites) at sub-cellular resolution in situ [26].…”

“…Such "in-situ"or "dynamic" patterning has been realized, for example, by using photoresponsive polymers [23,24] or laser ablation [25,26], just to name a few. We previously reported on the application of laser ablation phenomena to create growth pathways of neuronal processes (neurites) at sub-cellular resolution in situ [26]. Briefly, the working principle of the method is as follows: (1) Primary neurons are first grown on a micropatterned surface, (2) after supplementing the growth medium with Ln, focused femtosecond laser is scanned across the non-permissive area to ablate non-permissive compounds, (3) Ln adsorbs on the laserscanned pathway, and finally (4) neurites elongate on the pathway.…”

Dynamic photopatterning of cellsin situby Q-switched neodymium-doped yttrium ortho-vanadate laser

“…26 Previously our group developed a femto-second laser induced in-situ micro-fabrication method to array cells on a platform with micrometer-scale cell-adhering domains on a cytophobic surface under culture conditions. 27,28 The method was based on photochemical ablation. 28 In terms of promoting the use of in-situ lithography in biological research, frequent tuning requirements and high costs of the femto-second laser are prohibitive.…”

“…27,28 The method was based on photochemical ablation. 28 In terms of promoting the use of in-situ lithography in biological research, frequent tuning requirements and high costs of the femto-second laser are prohibitive. Additionally, the engraving speed of Ti: sapphire is only around 20 μm∕s with a pulse frequency of 1 kHz, 27 which is too slow to make a pattern in a platform of 3 to 4 cm 2 .…”