Femtosecond-laser-assisted spatial cell adhesion to microstructured surface geometry

Surface geometry has had an influence on the surface property, in addition to the intrinsic surface energy, of materials. Many physical surface modification methods had been proposed to control the solid surface geometry for modification of surface properties. Recently, short-pulse lasers were utilized to perform nano-texturing onto metallic and polymer substrates for the improvement of surface properties. Most of the papers reported that the hydrophilic metallic surface was modified to have a higher contact angle than 120–150°. Little studies explained the relationship between surface geometry and surface properties. In the present study, the laser micro-/nano-texturing was developed to describe this surface-geometric effect on the static contact angles for pure water. Micropatterns with multi spatial frequencies are designed and synthesized into a microtexture. This tailored microtexture was utilized to prepare for computer aided machining (CAM) data to control the femtosecond laser beams. The nano-length ripples by laser induced periodic surface structuring (LIPSS) supposed onto this microtexture to form the micro-/nano-texture on the AISI304 substrate surface. Computational geometry was employed to describe this geometric profile. The fractal dimension became nearly constant by 2.26 and insensitive to increase of static contact angle (θ) for θ > 150°. Under this defined self-similarity, the micro-/nano-textured surface state was controlled to be super-hydrophobic by increasing the ratio of the highest spatial frequency in microtextures to the lowest one. This controllability of surface property on the stainless steels was supported by tailoring the wavelength and pitch of microtextures. Exposure testing was also used to evaluate the engineering durability of this micro-/nano-textured surface. Little change of the measured fractal dimension during the testing proved that this physically modified AISI304 surface had sufficient stability for its long-term usage in air.

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Enhanced Heat Collection Element Performance Through Surface Geometry

ASME 2011 5th International Conference on Energy Sustainability, Parts A, B, and C ◽

10.1115/es2011-54454 ◽

2011 ◽

Author(s):

Rebecca N. Webb ◽

Julie A. Horvath ◽

Allen G. Boartfield

Keyword(s):

Radiative Heat ◽

Angle Of Incidence ◽

Steam Generation ◽

Concentrated Solar Power ◽

Surface Geometry ◽

Smooth Test ◽

Microstructured Surface ◽

Test Pieces ◽

Microstructured Surfaces ◽

The Impact

Concentrated solar power produces electricity by using a mirror to focus sunlight on a fluid filled tube known as a heat collection element. The fluid inside the element is then used as a heat source for steam generation in a conventional steam turbine power plant. It is possible that adding microstructures to the surface of the conventionally smooth heat collection element could improve system efficiency, motivating the need for an improved understanding of the radiation characteristics of a microstructured surface. The goal of this work was to experimentally determine the impact of different microscale geometries on net radiative heat gain when angle of incidence was varied. Five test pieces, one with a smooth surface and four with microstructured surfaces were compared experimentally for a given infrared energy input and flow rate and five different angles of incidence. Over the entire range of angles the microstructured test pieces absorbed more energy than the smooth test piece.

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Femtosecond Laser-Induced Surface Texturing and Crystallization of a-Si:H Thin Film

ASME 2010 International Manufacturing Science and Engineering Conference, Volume 2 ◽

10.1115/msec2010-34271 ◽

2010 ◽

Cited By ~ 1

Author(s):

Hongliang Wang ◽

Panjawat Kongsuwan ◽

Gen Satoh ◽

Y. Lawrence Yao

Keyword(s):

Thin Film ◽

Solar Cell ◽

Femtosecond Laser ◽

Laser Processing ◽

Light Trapping ◽

Surface Texturing ◽

Surface Geometry ◽

Femtosecond Laser Processing ◽

Stability Issues ◽

Surface Morphologies

Hydrogenated amorphous silicon (a-Si:H) thin films have been considered for use in solar cell applications because of their significantly reduced cost, however, the overall efficiency and stability are less than that of their bulk crystalline counterparts. Limited work has been performed on solving the efficiency and stability issues of a-Si:H simultaneously. In this study, both surface texturing and crystallization on a-Si:H thin film are achieved through one-step femtosecond laser processing in water. Light absorption is enhanced by light trapping based on surface geometry changes, and the formation of a mixture of hydrogenated microcrystalline silicon (μc-Si:H) and a-Si:H after crystallization suggests that the overall stability may be increased. Furthermore, the formation mechanism for the surface spikes is discussed. A comparison of absorptance spectra for various surface morphologies and crystallinities shows that the combination of surface texturing and crystallization induced by femtosecond laser processing is very promising for a-Si:H thin film solar cell applications.

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Morphological Observations of Mesenchymal Stem Cell Adhesion to a Nanoperiodic-Structured Titanium Surface Patterned Using Femtosecond Laser Processing

Japanese Journal of Applied Physics ◽

10.1143/jjap.51.125203 ◽

2012 ◽

Vol 51 ◽

pp. 125203 ◽

Cited By ~ 1

Author(s):

Kei Oya ◽

Shun Aoki ◽

Kazunori Shimomura ◽

Norihiko Sugita ◽

Kenji Suzuki ◽

...

Keyword(s):

Stem Cell ◽

Cell Adhesion ◽

Mesenchymal Stem Cell ◽

Femtosecond Laser ◽

Laser Processing ◽

Titanium Surface ◽

Femtosecond Laser Processing

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Biomimetic hierarchical micro/nano texturing of TiAlV alloys by femtosecond laser processing for the control of cell adhesion and migration

Physical Review Materials ◽

10.1103/physrevmaterials.4.056008 ◽

2020 ◽

Vol 4 (5) ◽

Author(s):

M. Martínez-Calderon ◽

R. J. Martín-Palma ◽

A. Rodríguez ◽

M. Gómez-Aranzadi ◽

J. P. García-Ruiz ◽

...

Keyword(s):

Cell Adhesion ◽

Femtosecond Laser ◽

Laser Processing ◽

Femtosecond Laser Processing ◽

Cell Adhesion And Migration ◽

And Migration

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Cell Adhesion-Dependent Biphasic Axon Outgrowth Elucidated by Femtosecond Laser Impulse

10.1101/2021.10.10.463848 ◽

2021 ◽

Author(s):

Sohei Yamada ◽

Kentaro Baba ◽

Naoyuki Inagaki ◽

Hosokawa Yoichiroh

Keyword(s):

Cell Adhesion ◽

Femtosecond Laser ◽

Adhesion Strength ◽

Growth Cone ◽

Traction Force ◽

Axonal Growth ◽

Flow Speed ◽

Axon Outgrowth ◽

Axonal Growth Cone ◽

Laminin Binding

Axon outgrowth is promoted by the mechanical coupling between the dynamic actin cytoskeleton and adhesive substrates via clutch and adhesion molecules in the axonal growth cone. In this study, we utilized a femtosecond laser-induced impulse to break the coupling between an axonal growth cone and an adhesive substrate, enabling us to evaluate the strength of the binding between proteins in the growth cone and a laminin substrate, and also determine the contribution of adhesion strength to axon outgrowth. We found that the adhesion strength of axonal L1 cell adhesion molecule (L1CAM)-laminin binding increased with the density of the laminin substrate. In addition, fluorescent speckle microscopy revealed that the retrograde flow of actin filaments in the axonal growth cone was dependent on the laminin density such that the flow speed reduced with increasing L1CAM-laminin binding. However, axon outgrowth did not increase monotonically with increased L1CAM-laminin binding but rather exhibited biphasic behavior, in which the outgrowth was suppressed by excessive L1CAM-laminin binding. Our quantitative evaluations of the adhesion strength suggest that the biphasic outgrowth is regulated by the balance between traction force and adhesion strength as a result of changes in the number of L1CAM-laminin interactions. These results imply that adhesion modulation is key to the regulation of axon guidance.

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Wetting Control in the Layered Polymer-silver Thin Film via Femtosecond Laser Microstructuring

Communications in Physics ◽

10.15625/0868-3166/29/1/13503 ◽

2019 ◽

Vol 29 (1) ◽

pp. 71

Author(s):

Sofia Filippovna Umanskaya ◽

Pavel Aleksandrovich Danilov ◽

Seigey Ivanovich Kudryashov ◽

Andrey Andreevich Rudenko ◽

Andrey Alekseevich Ionin

Keyword(s):

Thin Film ◽

Femtosecond Laser ◽

Laser Pulses ◽

Femtosecond Laser Pulses ◽

Side View ◽

Microstructured Surface ◽

Water Wetting ◽

Silver Thin Film ◽

Pulse Energies ◽

Layered Thin Film

Water wetting of a structured multi-layered thin film consisting of bottom silver and top polymer layers microstructured by femtosecond laser pulses was studied. The periodic trenches were ablatively produced on the top polymer layer of the film using 515-nm, 220-fs pulses of an ytterbium-doped fiber laser at different pulse energies and the repetition rate of 20 kHz. The topography of the structured film was observed by means of a JEOL 7001F scanning electron microscope and its water wetting angles were measured by side-view microscopic imaging. The wetting angle on the microstructured surface was 144°, comparing to 83° at the raw unstructured surface of the film.

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