N-Heterocyclic carbene-based gold etchants

• Robert B. Chevalier,
• Justin Pantano,
• Matthew K. Kiesewetter and
• Jason R. Dwyer

Beilstein J. Nanotechnol. 2023, 14, 865–871, doi:10.3762/bjnano.14.71

• but also the potential for deliberate etching, with the outcome determined by choice of chemically synthesized organic species and solvent. Keywords: gold etchant; microfabrication; N-heterocyclic carbenes; self-assembled monolayer (SAM); thin films; Introduction Self-assembled monolayers (SAMs) are

• conditions that the thiol-linked monolayer can be exposed to, prompting the development of alternative surface linking chemistry [12]. N-Heterocyclic carbene (NHC)-based monolayers have received increasing attention for their reported stability under a variety of harsh conditions [11][13][14][15][16]. Indeed

• , an NHC-based monolayer has even been shown to protect against thiol displacement on gold surfaces [13]. Thus, in spite of the challenges that can be presented by NHC synthesis [17], they offer appeal even in light of the more general commercial availability of a wide range of thiols. The covalent

Silver-based SERS substrates fabricated using a 3D printed microfluidic device

• Phommachith Sonexai,
• Minh Van Nguyen,
• Bui The Huy and
• Yong-Ill Lee

Beilstein J. Nanotechnol. 2023, 14, 793–803, doi:10.3762/bjnano.14.65

• assembled into a monolayer on a liquid/air interface and deposited onto a porous silicon array prepared through a metal-assisted chemical etching approach. By using the developed microfluidic device, enhancement factors of the Raman signal for rhodamine B (at 10−9 M) and melamine (at 10−7 M) of 8.59 × 106

• monolayer of Ag NPs appeared at the methanol/air interface. The PS@Ag substrates were created by depositing a monolayer of Ag NPs on the substrate surface after allowing the methanol to slowly evaporate under ambient conditions. SERS substrate characterization Raman spectra were obtained using a 24 mW laser

• homogeneous results because of the even deposition of the self-assembled monolayer of Ag NPs on the PS substrate. Detection of melamine using PS@Ag SERS substrate SERS spectra of MLM solutions at different concentrations (10−7 to 10−3 M) on the PS@Ag substrates were recorded, as shown in Figure 6a. The Raman

On the use of Raman spectroscopy to characterize mass-produced graphene nanoplatelets

• Keith R. Paton,
• Konstantinos Despotelis,
• Naresh Kumar,
• Piers Turner and
• Andrew J. Pollard

Beilstein J. Nanotechnol. 2023, 14, 509–521, doi:10.3762/bjnano.14.42

• lateral size of 218 nm. We did not attempt to give a number of layers for these flakes. Yet, we do note that while the natural interlayer spacing for graphite is 0.34 nm, it has been reported previously that for similarly produced flakes, monolayer flakes had a measured thickness of 2 nm, with each

• additional monolayer adding 0.95 nm to the thickness [25]. Graphite addition Raman spectroscopy results Samples of GNPref with different amounts of added graphite were analysed with Raman spectroscopy. As shown in Figure 2, the spectrum measured from pure graphite is distinct from that of the GNPref with a

Molecular nanoarchitectonics: unification of nanotechnology and molecular/materials science

• Katsuhiko Ariga

Beilstein J. Nanotechnol. 2023, 14, 434–453, doi:10.3762/bjnano.14.35

• creating a self-assembled monolayer of a diacetylene compound (10,12-nonacosazinoic acid) adsorbed on a graphite surface and biased with a scanning tunneling microscope probe [111]. By positioning the probe at a specific site, the polymerization of the chains was induced within defined small regions, and

Overview of mechanism and consequences of endothelial leakiness caused by metal and polymeric nanoparticles

• Magdalena Lasak and
• Karol Ciepluch

Beilstein J. Nanotechnol. 2023, 14, 329–338, doi:10.3762/bjnano.14.28

• considered one of the best materials with anticancer properties. Most of the administered NPs that end up in the bloodstream interact with the endothelial layer. The interaction of the NPs with the endothelium widens the existing gaps or induces new ones in the monolayer of vascular endothelial cells, thus

• junctions, which are a cluster of transmembrane channels located throughout the vascular system. The intercellular junctions between endothelial cells play an important role in maintaining the monolayer integrity, but they also connect cells in a dynamic and communicative manner [13][14]. Any change in

• important permeability barrier for NPs, which is of key importance for their medical applications [5][14]. The ability of NPs to cross the endothelial monolayer depends on both the physicochemical properties of the NPs and the biology and physiology of the vessels themselves [20]. Understanding the

Structural, optical, and bioimaging characterization of carbon quantum dots solvothermally synthesized from o-phenylenediamine

• Zoran M. Marković,
• Milica D. Budimir,
• Martin Danko,
• Dušan D. Milivojević,
• Pavel Kubat,
• Danica Z. Zmejkoski,
• Vladimir B. Pavlović,
• Marija M. Mojsin,
• Milena J. Stevanović and
• Biljana M. Todorović Marković

Beilstein J. Nanotechnol. 2023, 14, 165–174, doi:10.3762/bjnano.14.17

• (obtained from ATCC culture collection) were plated in 96-well flat-bottom plates at a concentration of 1 × 104 cells/well, grown in a humidified atmosphere of 95% air and 5% CO2 at 37 °C, and maintained as monolayer cultures in RPMI-1640 medium supplemented with 100 µg/mL streptomycin, 100 U/mL penicillin

• which MRC5 cells were maintained as monolayer cultures, was replaced with undiluted sample extract (100%), and 50% and 25% sample extracts (prepared by diluting sample extracts with fresh RPMI-1640). After 48 h of treatment with sample extracts, cell proliferation was determined using MTT reduction

Liquid phase exfoliation of talc: effect of the medium on flake size and shape

• Samuel M. Sousa,
• Helane L. O. Morais,
• Joyce C. C. Santos,
• Ana Paula M. Barboza,
• Bernardo R. A. Neves,
• Elisângela S. Pinto and
• Mariana C. Prado

Beilstein J. Nanotechnol. 2023, 14, 68–78, doi:10.3762/bjnano.14.8

• pharmaceutical and cosmetics uses [17]. It was shown that monolayer talc has outstanding mechanical properties of the same order of magnitude as graphene [12]. The breaking strength for uniaxial deformations ranges from 29 to 33 N·m−1, and the two-dimensional elasticity modulus is E = 181 N·m−1. Also, talc’s

• exfoliation medium on size and shape less evident. Therefore, a single centrifugation step of one hour only at 1000g was employed. Such low acceleration will not produce a monolayer-rich solution [26], which is crucial for the analysis we aim to perform. Atomic force microscopy characterization of flake size

Gap-directed chemical lift-off lithographic nanoarchitectonics for arbitrary sub-micrometer patterning

• Chang-Ming Wang,
• Hong-Sheng Chan,
• Chia-Li Liao,
• Che-Wei Chang and
• Wei-Ssu Liao

Beilstein J. Nanotechnol. 2023, 14, 34–44, doi:10.3762/bjnano.14.4

• alkanethiol self-assembled monolayer (SAM) on Au to generate surface patterns that are orders of magnitude smaller than structures on the original elastomer stamp. The smallest achieved feature dimension is 5 nm using a micrometer-scale structured stamp in a chemical lift-off lithography (CLL) process

• -off lithography; gap; self-assembled monolayer; sub-micrometer; surface patterning; Introduction The development of lithographic techniques is crucial to the advancement of the electronics and semiconductor industry, the backbones of modern technology. Advances in photolithography have pushed the

• ][18][19]. Instead of transferring ink molecules from a stamp reservoir, this technique selectively removes alkanethiol molecules from a self-assembled monolayer (SAM) covered flat Au surface. An oxygen-plasma-activated polydimethylsiloxane (PDMS) stamp bearing patterns originating from a silicon

Two-step single-reactor synthesis of oleic acid- or undecylenic acid-stabilized magnetic nanoparticles by thermal decomposition

• Mykhailo Nahorniak,
• Pamela Pasetto,
• Jean-Marc Greneche,
• Volodymyr Samaryk,
• Sandy Auguste,
• Anthony Rousseau,
• Nataliya Nosova and
• Serhii Varvarenko

Beilstein J. Nanotechnol. 2023, 14, 11–22, doi:10.3762/bjnano.14.2

• values of 3.1 nm for the sample TMO-I and 9.1 or 12.0 nm for the samples TMU-IV or TMU-V, respectively, were obtained. Based on the fact that the length of the OA molecule is 1.9–2.1 nm, it can be assumed that the core of the TMO-I particle is a coat with a monolayer of OA. In contrast, the shell

Photoelectrochemical water oxidation over TiO₂ nanotubes modified with MoS₂ and g-C₃N₄

• Phuong Hoang Nguyen,
• Thi Minh Cao,
• Tho Truong Nguyen,
• Hien Duy Tong and
• Viet Van Pham

Beilstein J. Nanotechnol. 2022, 13, 1541–1550, doi:10.3762/bjnano.13.127

• the MoS2 phase in the composite from the XRD pattern of MoS2/TNAs. The (002) plane indicates the multilayer structure of MoS2 materials, the (001) plane indicates a monolayer structure of MoS2 [37][46]. Therefore, the disappearing (002) reflection and the remaining (001) reflection show that the

Rapid and sensitive detection of box turtles using an electrochemical DNA biosensor based on a gold/graphene nanocomposite

• Abu Hashem,
• M. A. Motalib Hossain,
• Ab Rahman Marlinda,
• Mohammad Al Mamun,
• Khanom Simarani and
• Mohd Rafie Johan

Beilstein J. Nanotechnol. 2022, 13, 1458–1472, doi:10.3762/bjnano.13.120

• -based biosensing [65]. The Gooding Group published a method for measuring DNA hybridisation by voltammetry on gold electrodes using methylene blue as an intercalator and a self-assembled alkanethiol monolayer. N-hydroxysulfosuccinimide (NHS) and N-(3-dimethylamino) propyl-N-ethylcarbodiimide

• hydrochloride (EDC) were used to covalently link DNA and oligonucleotides to a carboxylate-terminated alkanethiol self-assembled monolayer (SAM) performed on a gold electrode (AuE) [70]. The Lisdat group described a label-free impedimetric sensor for the detection of hybridisation events which is based on short

Orally administered docetaxel-loaded chitosan-decorated cationic PLGA nanoparticles for intestinal tumors: formulation, comprehensive in vitro characterization, and release kinetics

• Sedat Ünal,
• Osman Doğan and
• Yeşim Aktaş

Beilstein J. Nanotechnol. 2022, 13, 1393–1407, doi:10.3762/bjnano.13.115

• and free DCX were carried out using the Caco-2 cell line. Drug molecules have to overcome several barriers throughout the GIT, including the mucus layer, intestinal epithelial cells, and the endothelium of the capillaries. Among them, the monolayer of epithelial cells plays an essential role in the

• absorption of drugs. Therefore, the Caco-2 cell line derived from a human colorectal carcinoma was employed to simulate the epithelial cell layer. A monolayer of cells should have a transepithelial electrical resistance of around 500 Ω·cm2 to show similarity with intestinal lumen [70][71][72]. In Table 5

• added to the basolateral region. The cell monolayer was incubated with the formulations at 37 °C for 4 h. At predetermined time intervals, 0.3 mL samples were taken from the basolateral side and replaced with fresh medium. For each sample, the DCX amount was analyzed by validated UV–vis

Design of surface nanostructures for chirality sensing based on quartz crystal microbalance

• Yinglin Ma,
• Xiangyun Xiao and
• Qingmin Ji

Beilstein J. Nanotechnol. 2022, 13, 1201–1219, doi:10.3762/bjnano.13.100

• MA (Figure 1) [26]. The immobilization of ʟ-Phe on QCM sensors was through a two-step assembling process. A 4-aminothiophenol (ATP) monolayer was firstly adsorbed on the QCM surface by chemical Au–S bonding. Then, 4-NH2-ʟ-Phe was bound by a diazo-coupling reaction to form a monolayer with ʟ-Phe. The

• , poly(acryloyl-ʟ(ᴅ)-valine) (ʟ(ᴅ)-PAV), as the chiral recognition layer for detection of ʟ-lecithin [36]. They found that ʟ(ᴅ)-PAV possesses larger chirality than the valine enantiomer-containing monolayer of 2-mercaptoacetyl-ʟ(ᴅ)-valine (ʟ(ᴅ)-MAV). The frequency responses by QCM indicated that ʟ

• were almost forming a monolayer on the surface of the QCM electrode. Compared with the nonimprinted polymer nanoparticle (NIP) film, MIP nanoparticle films displayed higher adsorption ability for ʟ-histidine, which was approx. 5.8 times higher than that for ᴅ-histidine and 2.2 times higher than that

A cantilever-based, ultrahigh-vacuum, low-temperature scanning probe instrument for multidimensional scanning force microscopy

• Hao Liu,
• Zuned Ahmed,
• Sasa Vranjkovic,
• Manfred Parschau,
• Andrada-Oana Mandru and
• Hans J. Hug

Beilstein J. Nanotechnol. 2022, 13, 1120–1140, doi:10.3762/bjnano.13.95

Influence of water contamination on the sputtering of silicon with low-energy argon ions investigated by molecular dynamics simulations

• Grégoire R. N. Defoort-Levkov,
• Alan Bahm and
• Patrick Philipp

Beilstein J. Nanotechnol. 2022, 13, 986–1003, doi:10.3762/bjnano.13.86

• , for typical vacuum conditions a monolayer of water is formed within minutes. Results and Discussion Sample characteristics and contaminant effects At first, bond length distributions were calculated to observe the effect of the water contaminant on these distributions. The nominal Si–Si bond in a

• 100 eV sputtering processes. We used MD simulations for irradiation with argon, with fluences up to 2.6 × 1015 ions/cm2 and ions of silicon samples with a clean surface and covered with a monolayer of water molecules. Contaminants adsorbed on the sample surface amplify the damage done by the argon

Bioselectivity of silk protein-based materials and their bio-inspired applications

• Hendrik Bargel,
• Vanessa T. Trossmann,
• Christoph Sommer and
• Thomas Scheibel

Beilstein J. Nanotechnol. 2022, 13, 902–921, doi:10.3762/bjnano.13.81

• , antimicrobial, and antibiofouling properties, including the formation of an oriented monolayer of bacterial flagellin proteins on hydrophobic surfaces [73], a reduction of oral bacteria adhesion on dental brackets by more than 95% due to a reduced surface free energy [74], and the fabrication of antifouling

Self-assembly of C₆₀ on a ZnTPP/Fe(001)–p(1 × 1)O substrate: observation of a quasi-freestanding C₆₀ monolayer

• Guglielmo Albani,
• Michele Capra,
• Alessandro Lodesani,
• Alberto Calloni,
• Gianlorenzo Bussetti,
• Marco Finazzi,
• Franco Ciccacci,
• Alberto Brambilla,
• Lamberto Duò and
• Andrea Picone

Beilstein J. Nanotechnol. 2022, 13, 857–864, doi:10.3762/bjnano.13.76

• Fullerene (C60) has been deposited in ultrahigh vacuum on top of a zinc tetraphenylporphyrin (ZnTPP) monolayer self-assembled on a Fe(001)–p(1 × 1)O substrate. The nanoscale morphology and the electronic properties of the C60/ZnTPP/Fe(001)–p(1 × 1)O heterostructure have been investigated by scanning

• fullerene films stabilized directly on metal surfaces. Our results unveil a model system that could be useful in applications in which a quasi-freestanding monolayer of C60 interfaced with a metallic electrode is required. Keywords: fullerene; scanning tunneling microscopy; ultraviolet photoemission

• displayed in Figure 1b, where individual ZnTPP molecules are resolved. Figure 2 focuses on the surface morphology for a sub-monolayer coverage of C60 on the ZnTPP/Fe(001)–p(1 × 1)O substrate. C60 forms a compact film, composed of hexagonal domains extending for hundreds of nanometers. By considering that

Optimizing PMMA solutions to suppress contamination in the transfer of CVD graphene for batch production

• Chun-Da Liao,
• Andrea Capasso,
• Tiago Queirós,
• Telma Domingues,
• Fatima Cerqueira,
• Nicoleta Nicoara,
• Jérôme Borme,
• Paulo Freitas and
• Pedro Alpuim

Beilstein J. Nanotechnol. 2022, 13, 796–806, doi:10.3762/bjnano.13.70

• (ca. 1585 cm−1) and 2D (ca. 2700 cm−1) bands are typical of monolayer graphene [23][24][25][26]. The defect density appears minimal considering the negligible D band intensity at ca. 1350 cm−1 (Figure 2c) [27]. The Raman mapping in Figure 2d–i examines the whole crystal area [28]. The map and the

• ± 3.0 cm−1 (Figure 2f,i), implying high-quality monolayer graphene. Together, the data further support uniformity and crystallinity of the sample. The G phonon band arises from double degeneracy of iTO and iLO phonon modes (E2g symmetry) at the Brillouin zone center, which is an in-plane vibration of

• B2 mixture yields more consistent electric properties of the graphene channel, thanks to a homogenous and reproducible process. Such characteristics ultimately translate into a consistent sensor performance, which is pivotal for industrial fabrication. Conclusion Monolayer graphene films and single

A nonenzymatic reduced graphene oxide-based nanosensor for parathion

• Sarani Sen,
• Anurag Roy,
• Ambarish Sanyal and
• Parukuttyamma Sujatha Devi

Beilstein J. Nanotechnol. 2022, 13, 730–744, doi:10.3762/bjnano.13.65

• detection limit and long-term stability at room temperature. Graphene oxide (GO), consisting of a monolayer of sp2-hybridized carbon atom network, has already been used in electrocatalysis, nanoelectronics, bionanosensors, and sustainable energy storage systems due to its larger active surface area

Tunable high-quality-factor absorption in a graphene monolayer based on quasi-bound states in the continuum

• Jun Wu,
• Yasong Sun,
• Feng Wu,
• Biyuan Wu and
• Xiaohu Wu

Beilstein J. Nanotechnol. 2022, 13, 675–681, doi:10.3762/bjnano.13.59

• /bjnano.13.59 Abstract A tunable graphene absorber, composed of a graphene monolayer and a substrate spaced by a subwavelength dielectric grating, is proposed and investigated. Strong light absorption in the graphene monolayer is achieved due to the formation of embedded optical quasi-bound states in the

• makes the fabrication quite difficult. In this paper, motivated by the investigation in [28], a tunable graphene absorber, which consists of a graphene monolayer on a dielectric grating backed with a substrate, is designed and investigated. The paper is arranged as follows: First, we present the

• . A graphene monolayer is placed on a one-dimensional dielectric grating, under which a dielectric substrate is used to support the device. The dielectric grating is defined by the period d, the width w, and the thickness h. The refractive indices of grating and substrate are nh and ns, respectively

Reliable fabrication of transparent conducting films by cascade centrifugation and Langmuir–Blodgett deposition of electrochemically exfoliated graphene

• Teodora Vićentić,
• Stevan Andrić,
• Vladimir Rajić and
• Marko Spasenović

Beilstein J. Nanotechnol. 2022, 13, 666–674, doi:10.3762/bjnano.13.58

• (DMEU), and ortho-dichlorobenzene (o-DCB) [12][17][18]. Exfoliation in NMP has led to minimally oxidized graphene sheets with approximately 28% monolayer flakes, and more than 75% of sheets with a thickness of less than six layers [12]. An alternative to LPE that has subsequently been developed is

Revealing local structural properties of an atomically thin MoSe₂ surface using optical microscopy

• Lin Pan,
• Peng Miao,
• Anke Horneber,
• Alfred J. Meixner,
• Pierre-Michel Adam and
• Dai Zhang

Beilstein J. Nanotechnol. 2022, 13, 572–581, doi:10.3762/bjnano.13.49

• addition, point defect-induced trions in monolayer WS2 on a nonconducting substrate can be visualized via photoluminescence in order to precisely explore the exciton binding energy [15]. The optical properties of edges and grain boundaries in 2D-TMDC materials have also been characterized by

• photoluminescence spectroscopy. Owing to the larger population of charge carriers, the photoluminescence from these structural defects of monolayer WS2 originates from the biexcitons under high-power excitation [16]. Interestingly, tilt boundaries in monolayer MoS2 induce strong photoluminescence enhancement and

• slightly decrease the in-plane electrical conductivity, whereas mirror twin boundaries lead to photoluminescence quenching and increase the conductivity [17]. Tip-enhanced Raman spectroscopy has been successfully used to visualize the point defect-related Raman vibrational modes in monolayer WS2 and edge

Effects of substrate stiffness on the viscoelasticity and migration of prostate cancer cells examined by atomic force microscopy

• Xiaoqiong Tang,
• Yan Zhang,
• Jiangbing Mao,
• Yuhua Wang,
• Zhenghong Zhang,
• Zhengchao Wang and
• Hongqin Yang

Beilstein J. Nanotechnol. 2022, 13, 560–569, doi:10.3762/bjnano.13.47

• cell migration, cells were cultured on PAA gels with different stiffness for 48 h, removed by trypsinization, and seeded at a density of 2 × 106 cells/mL in six-well plates to a confluent monolayer. A 10 µL pipet tip was used to scrape the cell monolayer in a straight line to create an empty gap. The

Ethosomal (−)-epigallocatechin-3-gallate as a novel approach to enhance antioxidant, anti-collagenase and anti-elastase effects

• Çiğdem Yücel,
• Gökçe Şeker Karatoprak,
• Sena Yalçıntaş and
• Tuğba Eren Böncü

Beilstein J. Nanotechnol. 2022, 13, 491–502, doi:10.3762/bjnano.13.41

• performed and the amounts of EGCG at the end of 24 hours were found to be 39.1%, 40.3%, and 39.8%, respectively. The lower cell permeation percentages of EGCG compared to that of the in vitro release study can be explained by the limiting aspect of the cell monolayer. ETHs are relatively new vesicular

Zinc oxide nanostructures for fluorescence and Raman signal enhancement: a review

• Ioana Marica,
• Fran Nekvapil,
• Maria Ștefan,
• Cosmin Farcău and
• Alexandra Falamaș

Beilstein J. Nanotechnol. 2022, 13, 472–490, doi:10.3762/bjnano.13.40

• on the tips of the nanorods by photodeposition or galvanic reduction [47][48]. Another facile method included layer-by-layer self-assembly deposition of chemically synthesized Au NPs, ZnO, and analyte molecules and resulted in dispersedly distributed ZnO particles onto a Au NP monolayer surface [49