Fabrication of high-aspect ratio silicon nanopillars for tribological experiments

Antonov, P.V.; Zuiddam, M.; Frenken, J.W.M.

doi:10.1117/1.jmm.14.4.044506

Cited by 12 publications

(11 citation statements)

References 19 publications

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“…For this, the micron-scale structures were fabricated on a Si substrate by a multi-step process, which was a combination of electron beam lithography and reactive ion etching techniques. Similar approaches to silicon patterning are described in a number of earlier works 44-47 . First, a pattern of e-beam resist was created on a Si surface using e-beam lithography.…”

Section: Methodsmentioning

confidence: 90%

“…The first approach was used for round and square/rectangular micron pillars, and was adapted from 14,15 . Briefly, using a multi-step process similar to that described in 44 , micron-scale pillars were fabricated on a silicon (Si) substrate by reactive ion etching. A pattern of hard-baked photoresist was created on a Si surface using UV lithography, to work as a mask for etching.…”

Section: Methodsmentioning

confidence: 99%

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Cell shape independent FtsZ dynamics in synthetically remodeled cells

Söderström¹,

Badrutdinov

Chan³

et al. 2018

Preprint

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46The FtsZ protein is a key regulator of bacterial cell division. It has been implicated in 47 acting as a scaffolding protein for other division proteins, being a force generator 48 during constriction, and more recently, as an active regulator of septal cell wall 49 production. During an early stage of the division cycle, FtsZ assembles into a 50 heterogeneous structure coined the "Z-ring" due to its resemblance to a ring confined 51 by the midcell geometry. While in vitro experiments on supported lipid bilayers have 52 shown that purified FtsZ can self-organize into a swirling ring roughly the diameter of 53 a bacterial cell, it is not known how, and if, membrane curvature affects FtsZ assembly 54 and dynamics in vivo. 55To establish a framework for examining geometrical influences on proper Z-ring 56 assembly and dynamics, we sculptured Escherichia coli cells into unnatural shapes, 57 such as squares and hearts, using division-and cell wall-specific inhibitors in a micro 58 fabrication scheme. This approach allowed us to examine FtsZ behavior in engineered 59 "Z-squares" and "Z-hearts", and in giant cells up to 50 times their normal volume. 60 Quantification of super-resolution STimulated Emission Depletion (STED) nanoscopy 61data showed that FtsZ densities in sculptured cells maintained the same dimensions 62 as their wild-type counterparts. Additionally, time-resolved fluorescence 63 measurements revealed that FtsZ dynamics were generally conserved in a wide range 64 of cell shapes. Based on our results, we conclude that the underlying membrane 65 environment is not a deciding factor for FtsZ filament maintenance and treadmilling in 66 vivo. 67 68 Introduction 69Most bacterial cells divide by binary fission, whereby one mother cell splits into two 70 identical daughters 1-3 . Decades of study have led to a detailed understanding of how 71 the cell division machinery, the divisome, carries out this task during the later stages 72 of the cell cycle 4,5 . At the heart of this process is the eukaryotic tubulin homologue, 73FtsZ 6 that, together with its membrane anchors ZipA and FtsA, forms an intermediate 74 structure called the proto-ring ( Fig. 1a) 7 . Functioning as a recruitment base, the proto-75 ring components then enlist the remaining essential division proteins to form a mature 76 'divisome' 5 . As soon as it is fully assembled, the divisome starts to constrict the cell 77 envelope by reshaping the septal geometry, ultimately leading to sequential closure of 78 the inner and outer membranes [8][9][10] . 79In rod-shaped model bacteria such as Escherichia coli and Bacillus subtilis, FtsZ is 80 believed to organize into short bundles of filaments, roughly 100 nm in length 11,12 , that 81 treadmill at the septum with a circumferential velocity in the order of 20-30 nm/s [13][14][15] . 82The treadmilling filaments guide and regulate septal peptidoglycan (PG-) production 83 and ingrowth, leading up to septation 16 . This mode of action may be limited to rod-84 shaped bacteria that have two separate PG-mach...

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Section: Methodsmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Cell shape independent FtsZ dynamics in synthetically remodeled cells

Söderström¹,

Badrutdinov

Chan³

et al. 2018

Preprint

View full text Add to dashboard Cite

show abstract

“…For this, the micron-scale structures were fabricated on a Si substrate by a multi-step process, which was a combination of electron beam lithography and reactive ion etching techniques. Similar approaches to silicon patterning have been successfully used in a number of earlier works 48 – 51 . First, a pattern of e-beam resist was created on a Si surface using e-beam lithography.…”

Section: Methodsmentioning

confidence: 98%

“… 14 , 15 . Using a multi-step process similar to that described previously 48 , micron-scale pillars were fabricated on a silicon (Si) substrate by reactive ion etching. A pattern of hard-baked photoresist was created on a Si surface using UV lithography, to work as a mask for etching.…”

Section: Methodsmentioning

confidence: 99%

Cell shape-independent FtsZ dynamics in synthetically remodeled bacterial cells

et al. 2018

View full text Add to dashboard Cite

FtsZ is the main regulator of bacterial cell division. It has been implicated in acting as a scaffolding protein for other division proteins, a force generator during constriction, and more recently, as an active regulator of septal cell wall production. FtsZ assembles into a heterogeneous structure coined the Z-ring due to its resemblance to a ring confined by the midcell geometry. Here, to establish a framework for examining geometrical influences on proper Z-ring assembly and dynamics, we sculpted Escherichia coli cells into unnatural shapes using division- and cell wall-specific inhibitors in a micro-fabrication scheme. This approach allowed us to examine FtsZ behavior in engineered Z-squares and Z-hearts. We use stimulated emission depletion (STED) nanoscopy to show that FtsZ clusters in sculpted cells maintain the same dimensions as their wild-type counterparts. Based on our results, we propose that the underlying membrane geometry is not a deciding factor for FtsZ cluster maintenance and dynamics in vivo.

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“…However, to enable SERS techniques for practical applications, SERS substrates need to be reproducible and highly sensitive . Advanced lithographic techniques, such as ion beam or electron beam lithography and nanosphere lithography, in combination with reactive ion etching (RIE), are effective techniques that can produce well‐controlled nanostructural arrays on Si substrate . Deposition of metal NPs on the surface of these Si nanostructure arrays can provide high concentration of hot spots, which is essential for application of these substrates as SERS sensors.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Ag‐modified nanocone frustum arrays with controlled shape as active substrates for surface‐enhanced Raman scattering

Mehrvar

Sadeghipari

Tavassoli

et al. 2019

J Raman Spectroscopy

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Surface‐enhanced Raman scattering (SERS) substrates utilizing the interparticle nanogaps as hot spots can provide ultrasensitive and geometry‐dependent enhancement factors in analyte detection. Here, we report theoretical and experimental studies on the optical properties of Ag nanoparticles‐decorated Si‐nanocone frustum (NCF) arrays with various geometrical dimensions to enable engineering of the most effective SERS substrate. Our fabrication steps include electron beam lithography, deep reactive‐ion etching, and metallization. In this regard, the effect of geometrical parameters including height, diameter, and slant angle, associated with Si‐NCF arrays, on optical properties and SERS effect are investigated. Results show that the NCF array with larger height and slant angle exhibit higher antireflection property and excellent performance for low‐concentration analyte molecules detection. Furthermore, our results show that the excitation of Mie resonances in NCF arrays leads to formation of near electric field distributions and enhancement of Si Raman lines. It is demonstrated that the strength of Si Raman line follows the trend of the integrated near electric fields in the excitation volume.

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Fabrication of high-aspect ratio silicon nanopillars for tribological experiments

Cited by 12 publications

References 19 publications

Cell shape independent FtsZ dynamics in synthetically remodeled cells

Cell shape independent FtsZ dynamics in synthetically remodeled cells

Cell shape-independent FtsZ dynamics in synthetically remodeled bacterial cells

Fabrication of Ag‐modified nanocone frustum arrays with controlled shape as active substrates for surface‐enhanced Raman scattering

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