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

A M Alshehri

doi:10.1063/7.0000432

Abstract

This article discusses the adhesion of C2C12 mouse myoblast cells to a microstructured polydimethylsiloxane (PDMS) surface patterned using femtosecond laser pulses. The wettability of the PDMS surface can be controlled by changing the writing-pulse energy; a hydrophilic surface is produced by low pulse energy, whereas high pulse energies lead to a superhydrophobic surface. The surface topography also varies with pulse energy. Images acquired with scanning electron microscopy show clear lines at low pulse energy, whereas at high energies, the lines are completely deformed by the presence of micro- and nano-structures. Thus, selective cell growth in the modified regions is affected by the energy of the laser pulses used for surface modification. In addition, the surface geometry (e.g., lines vs grids) of the modified regions affects the shape and alignment of C2C12 cells. Thus, we investigate the degree of cell alignment to modified lines fabricated with the same pulse energy and writing speed but with different inter-line spacings. The degree of alignment is quantified by the average value of a second-order Legendre polynomial. The results reveal that the degree of alignment of C2C12 cells to the surface lines decreases with the increase in spacing between lines.

Highlights

Preferential and spatial cell adhesion to biomedical materials entails material functionalization so that the biomedical material acts like the extracellular environment in a very controlled fashion
The surface geometry of the modified regions such as lines and grids affects the shape of C2C12 mouse myoblast cells
We show that the adhesion of C2C12 mouse myoblast cells to a microstructured PDMS surface can be spatially controlled by patterning the PDMS surface using femtosecond laser pulses

Summary

Introduction

Preferential and spatial cell adhesion to biomedical materials entails material functionalization so that the biomedical material acts like the extracellular environment in a very controlled fashion. The laser-induced periodic surface structure technique produces a smooth polystyrene film for the purpose of directed cell migration and oriented division in dental implants.[13,14] Nanopatterned surfaces have been developed with adhesive properties that allow selective immobilization of biomolecules only on the treated regions.[15] In addition, hydrophilic and superhydrophobic surfaces were produced on an ablated polydimethylsiloxane (PDMS) surface to fully control the adhesion of C2C12 cells to the PDMS surface.[16]. Laser deposition and laser-induced forward transfer techniques have been used to deposit thin films on surfaces to alter the chemistry and topography of biomedical materials.[19,20]. Both continuous-wave (CW) and short-pulse (i.e., ns) lasers can be used for surface modification, the use of ultrashort pulses has advantages over CW and ns pulsed lasers. Materials can be modified locally with very minimal collateral damage because the ablation is nonthermal (Coulomb explosion) due to the multiphoton photoionization and the ultrashort aspect of femtosecond pulses.[21,22] Surface scitation.org/journal/adv modification by femtosecond laser pulses or multiphoton lithography has been employed to investigate the cell response to different types of materials, including metals such as stainless steel,[23] titanium,[24] and gold;[25] polymers such as poly(methyl methacrylate),[26] polytetrafluoroethylene,[27] polyvinyl alcohol,[28] poly carbonates,[29] polystyrene,[30] and PDMS; bioactive glass;[31] semiconductors;[32] and ceramics.[33]

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Results

Conclusion