Bacterial Retention on Superhydrophobic Titanium Surfaces Fabricated by Femtosecond Laser Ablation

Abstract

Two-tier micro- and nanoscale quasi-periodic self-organized structures, mimicking the surface of a lotus Nelumbo nucifera leaf, were fabricated on titanium surfaces using femtosecond laser ablation. The first tier consisted of large grainlike convex features between 10 and 20 μm in size. The second tier existed on the surface of these grains, where 200 nm (or less) wide irregular undulations were present. The introduction of the biomimetic surface patterns significantly transformed the surface wettabilty of the titanium surface. The original surface possessed a water contact angle of θ(W) 73 ± 3°, whereas the laser-treated titanium surface became superhydrophobic, with a water contact angle of θ(W) 166 ± 4°. Investigations of the interaction of S. aureus and P. aeruginosa with these superhydrophobic surfaces at the surface-liquid interface revealed a highly selective retention pattern for two pathogenic bacteria. While S. aureus cells were able to successfully colonize the superhydrophobic titanium surfaces, no P. aeruginosa cells were able to attach to the surface (i.e., any attached bacterial cells were below the estimated lower detection limit).

Design and characterization of textured surfaces for applications in the food industry

“…As a result, S. aureus can adhere easily on a surface with spikes, whose spacing dimension is lower than the cellular size, by adapting its outer structure to the surface curvature. In these and other examples [23,[42][43][44], the emerging common concept is that the bacterial dimension defines a critical length-scale for bacterial adhesion-structures smaller than the cellular dimension have a negligible effect on bacterial attachment. This idea explains some conventions that have been introduced in the design of surfaces utilised in the food industry, for example, the rule that hygenic steel surfaces must have an average roughness lower than 0.8 µm dictated by the EHEDG (European Hygienic Equipment Design Group) and, additionally, the requirement of R a to be less than 1.6 µm, dictated by the ISO 4287 standard for cleanability [31,37].…”

Surface Treatments to Modulate Bioadhesion: A Critical Review

“…High-precision material processing with femtosecond laser pulses has been demonstrated [65] which allowed the fabrication of complicated two-and three-dimensional nanostructures with a structure size on the order of a few hundred nanometres. Nanostructures are produced at fluences close to the melting threshold of the material, short laser pulses with duration of less than a nanosecond (ns) melt only the micro-protrusions on the target surface giving rise to efficient formation of nanostructures [66]. These nanostructures will affect the hydrophobicity of surfaces potentially creating a superhydrophobic surface ( ≥150 θ o ) [67], a phenomenon known as the lotus effect.…”

“…One study evaluated bacterial retention on superhydrophobic titanium surfaces which had been fabricated by femtosecond laser ablation. The nanostructured titanium substrates were produced by laser ablation in liquid and the nanopillar structures were shown to prevent the attachment of Stapholococcus aureus [66] . This was in agreement with Chebolu et al [69] who also showed that micro-patterning of poly(dimethylsiloxane) (PDMS), using a CO 2 laser, had the potential to produce anti-bacterial surfaces when considering common Escherichia coli.…”

Влияние Поверхностной Обработки Фемтосекундным Импульсным Лазерным Излучением На Механические Свойства Субмикрокристаллического Титана

“…Управляемое изменение рельефа поверхности путем проведения ФЛО является перспективным направлени-ем повышения остеоинтеграции, поскольку нанорельеф поверхности особенным образом влияет на поведение различных типов клеток, а именно способствует повы-шению биоактивности остеобластов [5,6]. Управляемое изменение рельефа поверхности металлических имплан-татов посредством ФЛО и её влияние на их биосов-местимость являлись предметом ряда исследований по-верхностной обработки путем ФЛО [5][6][7].…”

“…Это позволяет осуществлять модификацию тонких приповерхностных слоев практи-чески без разогрева объема материала, который обычно сопровождается разупрочнением вследствие деградации СМК и НС состояний или полного их устранения вслед-ствие развития процессов возврата и рекристаллизации. По этой причине применение фемтосекундного лазера особенно актуально для модификации поверхности ти-тановых сплавов в СМК и НС состояниях, поскольку развитие указанных выше процессов, протекающих при повышенных температурах, приводит к уменьшению характеристик прочности рассматриваемых материалов, характерных для крупнозернистой структуры [3,4].Управляемое изменение рельефа поверхности путем проведения ФЛО является перспективным направлени-ем повышения остеоинтеграции, поскольку нанорельеф поверхности особенным образом влияет на поведение различных типов клеток, а именно способствует повы-шению биоактивности остеобластов [5,6]. Управляемое изменение рельефа поверхности металлических имплан-татов посредством ФЛО и её влияние на их биосов-местимость являлись предметом ряда исследований по-верхностной обработки путем ФЛО [5][6][7].…”