sensing, [4] regenerative medicine, [5] cell engineering [6] or cell fate control [7] represent prominent examples of the different areas that require the creation of active structural units at the nanometer scale.Despite 2D lithography of metallic nanostructures being very well-established through different techniques (in particular prominent photolithography and electron beam lithography), the creation of micro/ nanoscale 3D metallic structures with arbitrary shapes still constitutes a challenge. In this regard, electron and ion beam technologies have proven to be able to write 3D structures with high resolution. [8] A recent publication reports the creation of a Co double helix structure using focus electron beam-induced deposition, [9] although these techniques are not fully established and require the use of expensive equipment. Following a different approach, based on scanning probe lithography (SPL), Hengsteler and coauthors were able to electroplate sub-100 nm diameter copper pillars with the FluidFM technology and created other complex 3D arbitrary shapes. [10] Some authors propose to circumvent the current nanofabrication limitations by metalizing a pre-fabricated 3D scaffold using a twostep fabrication process. [11,12] Scaffolding can be achieved through additive manufacturingbased strategies, which have endowed the third dimension in macroscale printing. These strategies are currently being translated to nanoscale structuring. While direct laser writing techniques, such as two-photon lithography [13] are powerful candidates to create polymeric scaffolds, [12] SPL techniques are currently been developed to print 3D structures. SPL techniques provide a good alternative to the above-mentioned technologies, as they do not require very expensive facilities or clean rooms to obtain high pattern resolution. It has recently been demonstrated that using the FluidFM technology, a monomer ink can be patterned in a layer-by-layer writing process with intermediate curing steps which can dispense a UV curable polymer [14,15] or a customized polymer to achieve rapid surfaceinitiated crosslinking through versatile macro-crosslinkers. [16] Alternatively, 3D dip-pen nanolithography (DPN) printing was recently achieved by careful design of a polymer endowing it with a humidity-dependent behavior and adequate rheological properties. [17] While the design of printing inks has been extensively explored, much less effort has been devoted to the design and chemical functionalization of substrates to achieve different effects, such as hampering the ink spreading, due to tailored surface energies, [18] although some authors already stated While patterning 2D metallic nanostructures are well established through different techniques, 3D printing still constitutes a major bottleneck on the way to device miniaturization. In this work a fluid phase phospholipid ink is used as a building block for structuring with dip-pen nanolithography. Following a bioinspired approach that relies on ink-spreading inhibition, two processes are pre...
Thin films of Ti-Al-Cr-N were deposited onto glass substrates by means of the reactive magnetron co-sputtering of pure Cr and TiAl alloy targets in an atmosphere of Ar and N2. This investigation was carried out by adjusting the Cr-target power in order to increase the Cr amount in the films. The crystal structure of the films was investigated via X-ray diffraction (XRD). The elemental composition of the coatings was determined using Auger electron spectroscopy (AES). The electrical resistivity was measured using the four-point probe method, and the optical properties were characterized via ultraviolet/visible (UV/Vis) spectroscopy. The experimental results showed that, with a Cr concentration between 0 at% and 11.6 at%, a transition between phases from a single-phase hexagonal wurtzite-type structure to a single-phase cubic NaCl-type structure took place. The addition of Cr increased the crystallite size and, with it, the roughness of the coatings. All of the coatings exhibited an ohmic behavior at room temperature, and their surface electrical resistivity decreased from 490.1 ± 43.4 Ωcm to 1.5 ± 0.1 Ωcm as the chromium concentration increased. The transmittance of the coatings decreased, and the optical band gap (Egap) went from 3.5 eV to 2.3 eV with the addition of Cr. These electrical and optical properties have not been previously reported for these films.
Lipid Ink Spreading Inhibition In article number 2205590, Eider Berganza, Michael Hirtz, and co‐workers utilize dip‐pen nanolithography to print lipid patches layer‐by‐layer forming 3D structures on a surface coated with serum albumin stabilizing the structures. The lipid molecules transfer from the probe to the substrate through a water meniscus. To further improve their stability, lipid‐structures get covered with a few nanometers of gold through physical vapor deposition.
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