Ambient Climate Influences Anti-Adhesion between Biomimetic Structured Foil and Nanofibers

Abstract

Due to their uniquely high surface-to-volume ratio, nanofibers are a desired material for various technical applications. However, this surface-to-volume ratio also makes processing difficult as van der Waals forces cause nanofibers to adhere to virtually any surface. The cribellate spider Uloborus plumipes represents a biomimetic paragon for this problem: these spiders integrate thousands of nanofibers into their adhesive capture threads. A comb on their hindmost legs, termed calamistrum, enables the spiders to process the nanofibers without adhering to them. This anti-adhesion is due to a rippled nanotopography on the calamistrum. Via laser-induced periodic surface structures (LIPSS), these nanostructures can be recreated on artificial surfaces, mimicking the non-stickiness of the calamistrum. In order to advance the technical implementation of these biomimetic structured foils, we investigated how climatic conditions influence the anti-adhesive performance of our surfaces. Although anti-adhesion worked well at low and high humidity, technical implementations should nevertheless be air-conditioned to regulate temperature: we observed no pronounced anti-adhesive effect at temperatures above 30 °C. This alteration between anti-adhesion and adhesion could be deployed as a temperature-sensitive switch, allowing to swap between sticking and not sticking to nanofibers. This would make handling even easier.

Laser Direct Writing of Dual-Scale 3D Structures for Cell Repelling at High Cellular Density

“…The cells were grown in an incubator under standard conditions of temperature and humidity (37 °C, 5% CO 2 ). Notably, the NMP structures proved efficient anti-adhesive properties in an extremely humid environment, such as the one provided by the incubator, which is suitable for cell cultures, as compared to other cribellate spider calamistrum inspired structures [ 52 ], where the non-adhesive behavior was dependent on the environmental humidity.…”

Robustness of antiadhesion between nanofibers and surfaces covered with nanoripples of varying spatial period

“…With cribellate spiders, nature offers inspiration for overcoming nanofiber adhesion ( Joel et al, 2015 , 2020 ; Meyer et al, 2021 ; Figure 1 ), as they are capable of producing, processing, and handling nanofibers ( Hawthorn and Opell, 2002 ; Joel et al, 2015 , 2016 ; Bott et al, 2017 ; Grannemann et al, 2019 ). Cribellate spiders, a paraphyletic group within the web-building spiders (Araneae), incorporate thousands of ~15–30 nm thick nanofibers into their capture threads to give them adhesive properties ( Friedrich and Langer, 1969 ; Peters, 1992 ; Opell and Schwend, 2007 ; Joel et al, 2015 , 2023 ; Kronenberger and Vollrath, 2015 ; Bott et al, 2017 ; Joel and Baumgartner, 2017 ).…”

“…Such ripples can be found in the majority of species with similar dimensions of about 200–300 nm in both periodicity and height ( Ramírez, 2014 ; Joel et al, 2016 ; Heiss et al, 2018 ; Lifka et al, 2022 ). It has been demonstrated that similarly sized nanoripples reduce the adhesion between nanofibers of U. plumipes and biomimetic nanorippled surfaces ( Joel et al, 2020 ; Meyer et al, 2021 ).…”

Nanopatterning of Bionic Materials

“…Herein, only original research articles have been considered for publication. The present Special Issue includes contributions on the following research topics: Functionalization of Ti-based medical implants by means of laser-induced micro- and nanostructures for cell repellence as well as for osteoblastic proliferation and differentiation [ 2 , 3 , 4 ]; Polymer surfaces with antimicrobiotic and antiadhesive properties induced by laser-induced periodic surface structures (LIPSS) in connection with nanofibers or nanowires [ 5 , 6 , 7 ]; The generation of novel hybrid carbon nanotube materials for biosensing applications by means of laser-induced forward transfer (LIFT) [ 8 ]. …”

“…Polymer surfaces with antimicrobiotic and antiadhesive properties induced by laser-induced periodic surface structures (LIPSS) in connection with nanofibers or nanowires [ 5 , 6 , 7 ];…”