Creating superhydrophobic and antibacterial surfaces on gold by femtosecond laser pulses

Sohail A Jalil; Mahreen Akram; Javeed A Bhat; Jeffrey J Hayes; Subhash C Singh; Mohamed ElKabbash; Chunlei Guo

doi:10.1016/j.apsusc.2019.144952

Creating superhydrophobic and antibacterial surfaces on gold by femtosecond laser pulses

Appl Surf Sci. 2020 Mar 15:506:144952. doi: 10.1016/j.apsusc.2019.144952.

Authors

Sohail A Jalil^{1

2

3}, Mahreen Akram⁴, Javeed A Bhat⁵, Jeffrey J Hayes⁵, Subhash C Singh^{1

2}, Mohamed ElKabbash¹, Chunlei Guo^{1

2}

Affiliations

¹ The Institute of Optics, University of Rochester, Rochester, NY 14627, USA.
² GPL State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
³ University of Chinese Academy of Sciences, Beijing 100049, China.
⁴ Centre for Advanced Studies in Physics, Government College University, Lahore 54000, Pakistan.
⁵ Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY 14642, USA.

Abstract

Femtosecond laser-induced surface structuring is a promising technique for the large-scale formation of nano- and microscale structures that can effectively modify materials' optical, electrical, mechanical, and tribological properties. Here we perform a systematic study on femtosecond laser-induced surface structuring on gold (Au) surface and their effect on both hydrophobicity and bacterial-adhesion properties. We created various structures including subwavelength femtosecond laser-induced periodic surface structures (fs-LIPSSs), fs-LIPSSs covered with nano/microstructures, conic and 1D-rod-like structures ( $\leq$ 6 μm), and spherical nanostructures with a diameter $\geq$ 10 nm, by raster scanning the laser beam, at different laser fluences. We show that femtosecond laser processing turns originally hydrophilic Au to a superhydrophobic surface. We determine the optimal conditions for the creation of the different surface structures and explain the mechanism behind the formed structures and show that the laser fluence is the main controlling parameter. We demonstrate the ability of all the formed surface structures to reduce the adhesion of Escherichia coli (E. coli) bacteria and show that fs-LIPSSs enjoys superior antibacterial adhesion properties due to its large-scale surface coverage. Approximately 99.03% of the fs-LIPSSs surface is free from bacterial adhesion. The demonstrated physical inhibition of bacterial colonies and biofilm formation without antibiotics is a crucial step towards reducing antimicrobial-resistant infections.

Keywords: Anti-bacterial surfaces; Fs-LIPSSs; Nano- and microstructures; Superhydrophobic surfaces.

Abstract

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