Nanomaterials

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2 pages, 178 KiB

Open AccessEditorial

Nanopatterning of Bionic Materials

by Johannes Heitz

Nanomaterials 2023, 13(2), 233; https://doi.org/10.3390/nano13020233 - 4 Jan 2023

Cited by 1 | Viewed by 772

Abstract

The nanopatterning of bionic materials, performed by means of laser processes that utilize pulsed laser sources with short and ultrashort pulse durations, is a rapidly growing field [...] Full article

(This article belongs to the Special Issue Nanopatterning of Bionic Materials)

Research

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16 pages, 8097 KiB

Open AccessArticle

Polarization of Femtosecond Laser for Titanium Alloy Nanopatterning Influences Osteoblastic Differentiation

by Mathieu Maalouf, Alain Abou Khalil, Yoan Di Maio, Steve Papa, Xxx Sedao, Elisa Dalix, Sylvie Peyroche, Alain Guignandon and Virginie Dumas

Nanomaterials 2022, 12(10), 1619; https://doi.org/10.3390/nano12101619 - 10 May 2022

Cited by 13 | Viewed by 2526

Abstract

Ultrashort pulse lasers have significant advantages over conventional continuous wave and long pulse lasers for the texturing of metallic surfaces, especially for nanoscale surface structure patterning. Furthermore, ultrafast laser beam polarization allows for the precise control of the spatial alignment of nanotextures imprinted [...] Read more.

Ultrashort pulse lasers have significant advantages over conventional continuous wave and long pulse lasers for the texturing of metallic surfaces, especially for nanoscale surface structure patterning. Furthermore, ultrafast laser beam polarization allows for the precise control of the spatial alignment of nanotextures imprinted on titanium-based implant surfaces. In this article, we report the biological effect of beam polarization on human mesenchymal stem cell differentiation. We created, on polished titanium-6aluminum-4vanadium (Ti-6Al-4V) plates, a laser-induced periodic surface structure (LIPSS) using linear or azimuthal polarization of infrared beams to generate linear or radial LIPSS, respectively. The main difference between the two surfaces was the microstructural anisotropy of the linear LIPSS and the isotropy of the radial LIPSS. At 7 d post seeding, cells on the radial LIPSS surface showed the highest extracellular fibronectin production. At 14 days, qRT-PCR showed on the same surface an increase in osteogenesis-related genes, such as alkaline phosphatase and osterix. At 21 d, mineralization clusters indicative of final osteoinduction were more abundant on the radial LIPSS. Taken together, we identified that creating more isotropic than linear surfaces enhances cell differentiation, resulting in an improved osseointegration. Thus, the fine tuning of ultrashort pulse lasers may be a promising new route for the functionalization of medical implants. Full article

(This article belongs to the Special Issue Nanopatterning of Bionic Materials)

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14 pages, 4148 KiB

Open AccessEditor’s ChoiceArticle

Fabrication of Biomimetic 2D Nanostructures through Irradiation of Stainless Steel Surfaces with Double Femtosecond Pulses

by Matina Vlahou, Fotis Fraggelakis, Phanee Manganas, George D. Tsibidis, Anthi Ranella and Emmanuel Stratakis

Nanomaterials 2022, 12(4), 623; https://doi.org/10.3390/nano12040623 - 12 Feb 2022

Cited by 3 | Viewed by 1899

Abstract

Femtosecond laser induced changes on the topography of stainless steel with double pulses is investigated to reveal the role of parameters such as the fluence, the energy dose and the interpulse delay on the features of the produced patterns. Our results indicate that [...] Read more.

Femtosecond laser induced changes on the topography of stainless steel with double pulses is investigated to reveal the role of parameters such as the fluence, the energy dose and the interpulse delay on the features of the produced patterns. Our results indicate that short pulse separation (Δτ = 5 ps) favors the formation of 2D Low Spatially Frequency Laser Induced Periodic Surface Structures (LSFL) while longer interpulse delays (Δτ = 20 ps) lead to 2D High Spatially Frequency LIPSS (HSFL). The detailed investigation is complemented with an analysis of the produced surface patterns and characterization of their wetting and cell-adhesion properties. A correlation between the surface roughness and the contact angle is presented which confirms that topographies of variable roughness and complexity exhibit different wetting properties. Furthermore, our analysis indicates that patterns with different spatial characteristics demonstrate variable cell adhesion response which suggests that the methodology can be used as a strategy towards the fabrication of tailored surfaces for the development of functional implants. Full article

(This article belongs to the Special Issue Nanopatterning of Bionic Materials)

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11 pages, 3178 KiB

Open AccessArticle

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

by Marco Meyer, Gerda Buchberger, Johannes Heitz, Dariya Baiko and Anna-Christin Joel

Nanomaterials 2021, 11(12), 3222; https://doi.org/10.3390/nano11123222 - 27 Nov 2021

Cited by 6 | Viewed by 1754

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Nanopatterning of Bionic Materials)

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20 pages, 4601 KiB

Open AccessEditor’s ChoiceArticle

Spatial Period of Laser-Induced Surface Nanoripples on PET Determines Escherichia coli Repellence

by Anja M. Richter, Gerda Buchberger, David Stifter, Jiri Duchoslav, Andreas Hertwig, Jörn Bonse, Johannes Heitz and Karin Schwibbert

Nanomaterials 2021, 11(11), 3000; https://doi.org/10.3390/nano11113000 - 8 Nov 2021

Cited by 18 | Viewed by 2591

Abstract

Bacterial adhesion and biofilm formation on surfaces are associated with persistent microbial contamination, biofouling, and the emergence of resistance, thus, calling for new strategies to impede bacterial surface colonization. Using ns-UV laser treatment (wavelength 248 nm and a pulse duration of 20 ns), [...] Read more.

Bacterial adhesion and biofilm formation on surfaces are associated with persistent microbial contamination, biofouling, and the emergence of resistance, thus, calling for new strategies to impede bacterial surface colonization. Using ns-UV laser treatment (wavelength 248 nm and a pulse duration of 20 ns), laser-induced periodic surface structures (LIPSS) featuring different sub-micrometric periods ranging from ~210 to ~610 nm were processed on commercial poly(ethylene terephthalate) (PET) foils. Bacterial adhesion tests revealed that these nanorippled surfaces exhibit a repellence for E. coli that decisively depends on the spatial periods of the LIPSS with the strongest reduction (~91%) in cell adhesion observed for LIPSS periods of 214 nm. Although chemical and structural analyses indicated a moderate laser-induced surface oxidation, a significant influence on the bacterial adhesion was ruled out. Scanning electron microscopy and additional biofilm studies using a pili-deficient E. coli TG1 strain revealed the role of extracellular appendages in the bacterial repellence observed here. Full article

(This article belongs to the Special Issue Nanopatterning of Bionic Materials)

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12 pages, 3373 KiB

Open AccessArticle

Facile Fabrication of Hybrid Carbon Nanotube Sensors by Laser Direct Transfer

by Anca F. Bonciu, Mihaela Filipescu, Stefan I. Voicu, Thomas Lippert and Alexandra Palla-Papavlu

Nanomaterials 2021, 11(10), 2604; https://doi.org/10.3390/nano11102604 - 3 Oct 2021

Cited by 8 | Viewed by 1894

Abstract

Ammonia is one of the most frequently produced chemicals in the world, and thus, reliable measurements of different NH₃ concentrations are critical for a variety of industries, among which are the agricultural and healthcare sectors. The currently available technologies for the detection [...] Read more.

Ammonia is one of the most frequently produced chemicals in the world, and thus, reliable measurements of different NH₃ concentrations are critical for a variety of industries, among which are the agricultural and healthcare sectors. The currently available technologies for the detection of NH₃ provide accurate identification; however, they are limited by size, portability, and fabrication cost. Therefore, in this work, we report the laser-induced forward transfer (LIFT) of single-walled carbon nanotubes (SWCNTs) decorated with tin oxide nanoparticles (SnO₂ NPs), which act as sensitive materials in chemiresistive NH₃ sensors. We demonstrate that the LIFT-fabricated sensors can detect NH₃ at room temperature and have a response time of 13 s (for 25 ppm NH₃). In addition, the laser-fabricated sensors are fully reversible when exposed to multiple cycles of NH₃ and have an excellent theoretical limit of detection of 24 ppt. Full article

(This article belongs to the Special Issue Nanopatterning of Bionic Materials)

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15 pages, 4862 KiB

Open AccessArticle

Bimetallic Nanowires on Laser-Patterned PEN as Promising Biomaterials

by Jana Pryjmaková, Markéta Kaimlová, Barbora Vokatá, Tomáš Hubáček, Petr Slepička, Václav Švorčík and Jakub Siegel

Nanomaterials 2021, 11(9), 2285; https://doi.org/10.3390/nano11092285 - 2 Sep 2021

Cited by 7 | Viewed by 1784

Abstract

As inflammation frequently occurs after the implantation of a medical device, biocompatible, antibacterial materials must be used. Polymer–metal nanocomposites are promising materials. Here we prepared enhanced polyethylene naphthalate (PEN) using surface modification techniques and investigated its suitability for biomedical applications. The PEN was [...] Read more.

As inflammation frequently occurs after the implantation of a medical device, biocompatible, antibacterial materials must be used. Polymer–metal nanocomposites are promising materials. Here we prepared enhanced polyethylene naphthalate (PEN) using surface modification techniques and investigated its suitability for biomedical applications. The PEN was modified by a KrF laser forming periodic ripple patterns with specific surface characteristics. Next, Au/Ag nanowires were deposited onto the patterned PEN using vacuum evaporation. Atomic force microscopy confirmed that the surface morphology of the modified PEN changed accordingly with the incidence angle of the laser beam. Energy-dispersive X-ray spectroscopy showed that the distribution of the selected metals was dependent on the evaporation technique. Our bimetallic nanowires appear to be promising antibacterial agents due to the presence of antibacterial noble metals. The antibacterial effect of the prepared Au/Ag nanowires against E. coli and S. epidermidis was demonstrated using 24 h incubation with a drop plate test. Moreover, a WST-1 cytotoxicity test that was performed to determine the toxicity of the nanowires showed that the materials could be considered non-toxic. Collectively, these results suggest that prepared Au/Ag nanostructures are effective, biocompatible surface coatings for use in medical devices. Full article

(This article belongs to the Special Issue Nanopatterning of Bionic Materials)

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9 pages, 5211 KiB

Open AccessArticle

Femtosecond Laser-Processing of Pre-Anodized Ti-Based Bone Implants for Cell-Repellent Functionalization

by Martina Muck, Benedikt Wolfsjäger, Karoline Seibert, Christian Maier, Shaukat Ali Lone, Achim Walter Hassel, Werner Baumgartner and Johannes Heitz

Nanomaterials 2021, 11(5), 1342; https://doi.org/10.3390/nano11051342 - 20 May 2021

Cited by 11 | Viewed by 2975

Abstract

Microstructures and nanostructures can be used to reduce the adhesion of the cells on the auxiliary material. Therefore, the aim of our work was to fabricate laser-induced hierarchical microstructures and nanostructures by femtosecond laser-treatment (wavelength 1040 nm, pulse length 350 fs, repetition rates [...] Read more.

Microstructures and nanostructures can be used to reduce the adhesion of the cells on the auxiliary material. Therefore, the aim of our work was to fabricate laser-induced hierarchical microstructures and nanostructures by femtosecond laser-treatment (wavelength 1040 nm, pulse length 350 fs, repetition rates in the kHz range) to reduce the cell adhesion. Additionally, surface chemistry modification by optimized electrochemical anodization was used to further reduce the cell adhesion. For testing, flat plates and bone screws made of Ti-6Al-4V were used. Bone-forming cells (human osteoblasts from the cell line SAOS-2) were grown on the bone implants and additional test samples for two to three weeks. After the growth period, the cells were characterized by scanning electron microscopy (SEM). While earlier experiments with fibroblasts had shown that femtosecond laser-processing followed by electrochemical anodization had a significant impact on cell adhesion reduction, for osteoblasts the same conditions resulted in an activation of the cells with increased production of extracellular matrix material. Significant reduction of cell adhesion for osteoblasts was only obtained at pre-anodized surfaces. It could be demonstrated that this functionalization by means of femtosecond laser-processing can result in bone screws that hinder the adhesion of osteoblasts. Full article

(This article belongs to the Special Issue Nanopatterning of Bionic Materials)

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