3D Nanolithography by Means of Lipid Ink Spreading Inhibition

Abstract

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...

Contactless calibration of microchanneled AFM cantilevers for fluidic force microscopy

“…In particular, for automatized measurements this new approach for the InvOLS‐calibration can be easily implemented and will allow to determine InvOLS between single measurement series. As fluidic force microscopy is increasingly utilized to characterize cell–substrate interactions, 56 nano‐structuring, 58,59 and is utilized for sampling cells or cell organelles, 57 the here‐presented approach might be extremely useful due to the fact that the optical lever sensitivity can be determined in short time, that is, seconds, and most of all contact free. Thereby corrections for drift and prevention for contamination are easily implementable in the workflow, in particular for robotic approaches 21,42,43 …”

“…By varying the externally applied pressure, fluid can be aspirated and ejected via the aperture of the cantilever. 15 Thereby, various types of experimental procedures can be implemented for applications in cell biology, 25,[53][54][55][56][57] colloidal science, [16][17][18] the structuring of hydrogels and interfaces, 58,59 scanning ion conductance microscopy (SICM), 60,61 and the deposition of metals and colloidal particles. 62,63 The internal flow of liquid in the cantilever can be followed by particle image tracking 64 or by streaming potential measurements.…”

Odor Discrimination by Lipid Membranes

“…Lipid micro- and nano-structured droplets have formed on surfaces by dip-pen nanolithography [ 52 , 53 , 59 , 60 , 61 ], polymer-pen lithography [ 62 ], evaporative edge lithography [ 63 ], and nanointaglio printing [ 58 , 64 , 65 ]. Nanointaglio printing is the method used here, which involves printing lipid inks from micro- or nanostructured stamps, with the ink being transferred from the recesses of the stamps [ 58 , 64 , 65 ].…”

Nanoscale Confinement of Dip‐Pen Nanolithography Written Phospholipid Structures on CuZr Nanoglasses

“…[23] Dip-pen nanolithography for patterning lipids has been used on a wide variety of substrates such as silicon, glass, polymer, graphene, polystyrene, and titanium. [23][24][25] L-DPN utilizes an atomic force microscopy (AFM) tip, dipped into a lipid mixture as ink (with 1,2-dioleoyl-snglycero-3-phosphocholine (DOPC) as a main carrier), to deposit biomimetic lipid membranes onto surfaces (Figure 1b). Previously, L-DPN has been used for biomedical applications such as drug delivery, cell culture, biomarker detection and cancer cell detection, and protein screening.…”