Microneedle-based ocular drug delivery systems – recent advances and challenges

• Piotr Gadziński,
• Anna Froelich,
• Monika Wojtyłko,
• Antoni Białek,
• Julia Krysztofiak and
• Tomasz Osmałek

Beilstein J. Nanotechnol. 2022, 13, 1167–1184, doi:10.3762/bjnano.13.98

• photoresistant layer. The wafer is then etched. A distinction can be made between wet and dry etching. The wet etching process uses a potassium hydroxide solution, while dry etching includes the physical methods ion milling and sputtering and the chemical method high-pressure plasma [156]. Lithographic

Electrocatalytic oxygen reduction activity of AgCoCu oxides on reduced graphene oxide in alkaline media

• Iyyappan Madakannu,
• Indrajit Patil,
• Bhalchandra Kakade and
• Kasibhatta Kumara Ramanatha Datta

Beilstein J. Nanotechnol. 2022, 13, 1020–1029, doi:10.3762/bjnano.13.89

• et al. prepared supportless Ag nanowires and 1D mesoporous hollow AgPdPt nanotubes by micelle-assisted galvanic replacement followed by acid etching. They found that hollow AgPdPt structures exhibited a better ORR activity with onset and half-wave potential of 0.99 V and 0.90 V vs RHE, respectively

Effects of focused electron beam irradiation parameters on direct nanostructure formation on Ag surfaces

• Jānis Sniķeris,
• Vjačeslavs Gerbreders,
• Andrejs Bulanovs and
• Ēriks Sļedevskis

Beilstein J. Nanotechnol. 2022, 13, 1004–1010, doi:10.3762/bjnano.13.87

• distribution there. Under the assumption that carbon and carbon-containing silver areas are more susceptible to N plasma etching, we could theorize that carbon atoms in this particular case have reached up to 140 nm deep within the Ag layer. The carbon diffusion could have been caused by a number of reasons

• , radiolysis by collisions with electrons seeming like the most obvious one. It should be noted that N plasma treatment in this case also affected the clean Ag surface, turning it into an interfering thin film. We believe that controlled etching with plasma has the potential to explore the structure of metal

DNA aptamer selection and construction of an aptasensor based on graphene FETs for Zika virus NS1 protein detection

• Nathalie B. F. Almeida,
• Thiago A. S. L. Sousa,
• Viviane C. F. Santos,
• Camila M. S. Lacerda,
• Thais G. Silva,
• Rafaella F. Q. Grenfell,
• Flavio Plentz and
• Antero S. R. Andrade

Beilstein J. Nanotechnol. 2022, 13, 873–881, doi:10.3762/bjnano.13.78

• previously described by our group elsewhere [24]. The dimensions of the sensing region (100 μm × 100 μm) were defined by O2 plasma etching. The source and drain electrodes were fabricated by electron-beam evaporation of 2 nm/100 nm of Ti/Au, and we covered the metal contacts with a 10 μm thick passivation

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

• as a supporting layer to (i) retain the integrity of graphene during the wet-etching bath required to dissolve the metallic substrate and (ii) provide mechanical stability when transferring graphene to the target substrates. During this process, two primary external sources of contamination need to

• be considered: (i) metallic particles from the Cu or Ni etching process and (ii) PMMA residues after the removal and rinsing processes. Both contaminations are leading causes of undesired p-type doping in CVD graphene, accompanied by a deterioration of its electrical properties [19][20][21][22]. The

• single crystals using PMMA with different weight percentages and AMWs (Figure 1a–g). As detailed in the description of the graphene transfer process, after the Cu etching process (Supporting Information File 1, Figure S1b, step II), the PMMA-coated graphene is rinsed in a DI water bath at least three

Recent advances in nanoarchitectures of monocrystalline coordination polymers through confined assembly

• Lingling Xia,
• Qinyue Wang and
• Ming Hu

Beilstein J. Nanotechnol. 2022, 13, 763–777, doi:10.3762/bjnano.13.67

• fronts may be encapsulated in the single crystals [29][30][31][32][33][34][35][36][37][38]. When the encapsulated networks are removed by etching or dissolving, the previously occupied spaces can be freed, leaving periodic or random mesospace inside the single crystals [29][30][31][32][33][34][35][36][37

Nanoarchitectonics of the cathode to improve the reversibility of Li–O₂ batteries

• Hien Thi Thu Pham,
• Jonghyeok Yun,
• So Yeun Kim,
• Sang A Han,
• Jung Ho Kim,
• Jong-Won Lee and
• Min-Sik Park

Beilstein J. Nanotechnol. 2022, 13, 689–698, doi:10.3762/bjnano.13.61

• ratio of Zn/Co (x/y = 1/4, 1/1, and 4/1) in the starting materials. After carbonization at 900 °C and chemical etching with 1 M H2SO4, bimetallic ZnxCoy–C/CNT composites were successfully obtained to be used as cathode materials for LOBs. Figure 1b–d shows the morphologies of bimetallic Zn4Co1, Zn1Co1

• -step growth mechanism (i.e., nucleation and growth) [39]. The different formation mechanisms are mainly responsible for determining the particle sizes of ZIF-8 and ZIF-67. After carbonization and chemical etching processes, we obtained a series of ZnxCoy–C/CNT composites, as shown in Figure 1e–1g, in

• the carbonization process. After the carbonization and chemical etching processes, the sizes of the ZnxCoy particles were slightly decreased due to the thermal evaporation of organic linkers and metal ions, maintaining free spaces in the particles. According to the X-ray diffraction (XRD) patterns of

Fabrication and testing of polymer microneedles for transdermal drug delivery

• Vahid Ebrahiminejad,
• Zahra Faraji Rad,
• Philip D. Prewett and
• Graham J. Davies

Beilstein J. Nanotechnol. 2022, 13, 629–640, doi:10.3762/bjnano.13.55

• to grow to $50.6 billion by 2025 [6]. To enable mass manufacturing of MNs, factors such as reproducibility, fabrication precision, lower production cost, and time should be addressed. For instance, manufacturing techniques such as reactive ion etching and deep reactive ion etching incorporate

Investigation of electron-induced cross-linking of self-assembled monolayers by scanning tunneling microscopy

• Patrick Stohmann,
• Sascha Koch,
• Yang Yang,
• Christopher David Kaiser,
• Julian Ehrens,
• Jürgen Schnack,
• Niklas Biere,
• Dario Anselmetti,
• Armin Gölzhäuser and
• Xianghui Zhang

Beilstein J. Nanotechnol. 2022, 13, 462–471, doi:10.3762/bjnano.13.39

• V and +0.4 to +1.2 V. A z-resolution higher than 0.01 nm could be achieved. The STM tips were prepared from 0.375 mm polycrystalline tungsten wire (Alfa Aesar) by electrochemical etching in a 3 M NaOH solution. The instrument was calibrated by imaging HOPG with atomic resolution. The data was post

Electrostatic pull-in application in flexible devices: A review

• Teng Cai,
• Yuming Fang,
• Yingli Fang,
• Ruozhou Li,
• Ying Yu and
• Mingyang Huang

Beilstein J. Nanotechnol. 2022, 13, 390–403, doi:10.3762/bjnano.13.32

• quickly realize positioning and alignment of CNTs in 10–60 s. GR-NEM switches Based on the large-scale fabrication of graphene (GR) using CVD and oxygen plasma etching, GR-NEM switches have attracted the attention of researchers. Table 2 summarizes GR-NEM switch structures described in the literature. Two

• performance of the switches can also be affected by the surrounding environment. Capillary forces are occurring due to the humid environment during wet etching [24]. In addition, the design of NEM switches needs to consider the unique characteristics of the materials. For example, the shape of CNTs not only

Selected properties of Al_xZn_yO thin films prepared by reactive pulsed magnetron sputtering using a two-element Zn/Al target

• Witold Posadowski,
• Artur Wiatrowski,
• Jarosław Domaradzki and
• Michał Mazur

Beilstein J. Nanotechnol. 2022, 13, 344–354, doi:10.3762/bjnano.13.29

• the target (on-axis geometry) probably results from the destructive effect of the bombardment of the forming AlxZnyO films with negative oxygen ions, which was reported by many authors [11][13][14][15][17]. Negative oxygen ions (and also secondary electrons) directly form in the target etching zone

Thermal oxidation process on Si(113)-(3 × 2) investigated using high-temperature scanning tunneling microscopy

• Hiroya Tanaka,
• Shinya Ohno,
• Kazushi Miki and
• Masatoshi Tanaka

Beilstein J. Nanotechnol. 2022, 13, 172–181, doi:10.3762/bjnano.13.12

• oxidation modes – oxidation, etching, and transition modes – in the third of which both oxidation and etching occur. A precise temperature–pressure growth mode diagram was obtained via careful measurements for Si(113), and the results were compared with those for Si(111) in the present work and Si(001) in

• series of STM images of the filled state for oxidation at an oxygen pressure of 1.3 × 10−5 Pa and a sample temperature of 820 K. Under these conditions, only oxidation occurs; etching does not. The circle (a) shows one of the initial oxidation sites, appearing as a dark depression on the terrace. It is

• oxidation may occur at the extended terrace formed by the decorated silicon atoms. In contrast, the step position indicated by the broken line remains almost constant at the lower-right corner. Later, we will report that the step position can be pinned by the oxide. Oxidation and etching regime Figure 3

A comprehensive review on electrospun nanohybrid membranes for wastewater treatment

• Senuri Kumarage,
• Imalka Munaweera and
• Nilwala Kottegoda

Beilstein J. Nanotechnol. 2022, 13, 137–159, doi:10.3762/bjnano.13.10

• the unique properties of matter at dimensions between 1 and 100 nm. Since the discovery of nanotechnology, it has evolved continuously and now has become a technology that is indispensable in diverse disciplines. Among many techniques such as sintering, stretching, track etching, template leaching

• purification and treatment. The electrospun membranes have shown potential to overcome the bottlenecks of conventional membranes used in water purification, fabricated by techniques such as phase inversion, sintering, stretching, and track-etching. For instance, sintering and stretching, which are commonly

• [19]. Track etching also produces membranes of weak mechanical strength, and the technique is applicable onlyl for a limited number polymers. The track-etched membranes have low porosity and the technique is more expensive than electrospinning [1]. Phase separation is also a versatile membrane

Sputtering onto liquids: a critical review

• Anastasiya Sergievskaya,
• Adrien Chauvin and
• Stephanos Konstantinidis

Beilstein J. Nanotechnol. 2022, 13, 10–53, doi:10.3762/bjnano.13.2

Design aspects of Bi₂Sr₂CaCu₂O_8+δ THz sources: optimization of thermal and radiative properties

• Mikhail M. Krasnov,
• Natalia D. Novikova,
• Roger Cattaneo,
• Alexey A. Kalenyuk and
• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2021, 12, 1392–1403, doi:10.3762/bjnano.12.103

• on a flat portion of Bi-2212 surface, followed by argon-ion etching of the unprotected parts of Au and Bi-2212, the deposition of insulating SiO2 or CaF2 layers and a lift-off of the photoresist at the line. The depth of Bi-2212 etching at this stage (dm ≈ 200–400 nm) defines the height of mesas and

• photolithography and argon-ion etching. Mesa structures are formed at the overlap between the line and the electrodes, as indicated in Figure 1a. Figure 2a,b shows current–voltage (I–V) characteristics of mesas of whisker- and crystal-based devices, respectively. The I–V curves are fairly similar. They contain

Chemical vapor deposition of germanium-rich CrGe_x nanowires

• Vladislav Dřínek,
• Stanislav Tiagulskyi,
• Roman Yatskiv,
• Jan Grym,
• Radek Fajgar,
• Věra Jandová,
• Martin Koštejn and
• Jaroslav Kupčík

Beilstein J. Nanotechnol. 2021, 12, 1365–1371, doi:10.3762/bjnano.12.100

• structure of the prepared nanowires, unlike simple structures, enables further more extensive engineering of nanowire properties by specific technological steps (e.g., thermal annealing, etching, doping, and filling) in order to obtain, for example, catalytic nanowires with huge specific surface or hollow

Plasmon-enhanced photoluminescence from TiO₂ and TeO₂ thin films doped by Eu³⁺ for optoelectronic applications

• Marcin Łapiński,
• Jakub Czubek,
• Katarzyna Drozdowska,
• Anna Synak,
• Wojciech Sadowski and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2021, 12, 1271–1278, doi:10.3762/bjnano.12.94

• occur [39]. Additionally, a depth profile of concentration was measured. XPS results after etching of the TeO2:Eu film showed good chemical uniformity over the whole thickness of the layer, which is shown in Figure 8. After 8 min of etching the film was completely removed from the Corning glass

Morphology-driven gas sensing by fabricated fractals: A review

• Vishal Kamathe and
• Rupali Nagar

Beilstein J. Nanotechnol. 2021, 12, 1187–1208, doi:10.3762/bjnano.12.88

• -assisted chemical etching was used by Qin et al. [79] to prepare a dendritic array of Si/WO3 NW composites, which was tested for the detection of NO2 gas at room temperature. Figure 17a–e SEM and high-resolution transmission electron microscopy (HR-TEM) images of Si/WO3 NWs. Figure 17f shows the XRD

An overview of microneedle applications, materials, and fabrication methods

• Zahra Faraji Rad,
• Philip D. Prewett and
• Graham J. Davies

Beilstein J. Nanotechnol. 2021, 12, 1034–1046, doi:10.3762/bjnano.12.77

• biotherapeutics, drugs, and vaccines through the skin. A wide range of microneedle structure, design, geometry, and microneedle array densities is manufactured using different rapid prototyping and microfabrication technologies such as deep reactive ion etching (DRIE) [2], lithography [3], hot embossing [4], and

• microneedles in high-density two-dimensional arrays, although the resulting microneedles are restricted to lower aspect ratio and shorter height compared to in-plane microneedles if traditional microfabrication methods, such as wet and dry etching, are used. Hollow microneedles contain a lumen or internal

• injection moulding [61], wet chemical etching [75], reactive ion etching [2][76], hot embossing [4][5], laser drilling [77], lithography plus electroforming [78][79], drawing lithography [80][81], two-photon polymerization [5][82], and 3D printing [83][84]. To date, DRIE of silicon; micromoulding

Uniform arrays of gold nanoelectrodes with tuneable recess depth

• Elena O. Gordeeva,
• Ilya V. Roslyakov,
• Alexey P. Leontiev,
• Alexey A. Klimenko and
• Kirill S. Napolskii

Beilstein J. Nanotechnol. 2021, 12, 957–964, doi:10.3762/bjnano.12.72

• alternative approach includes bulk electrode structuring by deposition or etching techniques using self-assembled arrays of colloidal nanoparticles [15], liquid crystals [16], or track-etched membranes [17][18][19] as template or mask, respectively. Among porous templates, anodic aluminium oxide (AAO) allows

• mechanical polishing or ion etching and subsequent re-deposition of the current collector. It is worth noting that a great number of Au electrodes within the array is extremely important for a practical application of NEAs under the kinetic control of a target electrochemical process. In this case, the

• anodizing stage, the remaining Al was selectively dissolved in 10 vol % Br2 solution in CH3OH. Then, the barrier layer of the AAO template was removed by chemical etching in 3.5 M H3PO4 with electrochemical detection of the pore opening moment as described elsewhere [40]. The prepared AAO templates were

In situ transport characterization of magnetic states in Nb/Co superconductor/ferromagnet heterostructures

• Olena M. Kapran,
• Roman Morari,
• Taras Golod,
• Evgenii A. Borodianskyi,
• Vladimir Boian,
• Andrei Prepelita,
• Nikolay Klenov,
• Anatoli S. Sidorenko and
• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2021, 12, 913–923, doi:10.3762/bjnano.12.68

• the vacuum. We use a Nb target (99.95% purity) for deposition of S-layers, Co (99.95% purity) for F-layers, and Si (99.999%) for seeding bottom and protective top layers. MLs are grown on a Si(111) wafer. Prior to deposition, targets were precleaned by plasma-etching for 3 min and in addition for 1

• were used for the calibration of the etching rates of the films. MLs are patterned into micrometer-scale bridges with multiple contacts using photolithography and reactive ion etching. A scanning electron microscopy (SEM) image of one of the studied samples is shown in Figure 1a. Control of the

Comprehensive review on ultrasound-responsive theranostic nanomaterials: mechanisms, structures and medical applications

• Sepand Tehrani Fateh,
• Lida Moradi,
• Elmira Kohan,
• Michael R. Hamblin and
• Amin Shiralizadeh Dezfuli

Beilstein J. Nanotechnol. 2021, 12, 808–862, doi:10.3762/bjnano.12.64

Fate and transformation of silver nanoparticles in different biological conditions

• Barbara Pem,
• Marija Ćurlin,
• Darija Domazet Jurašin,
• Valerije Vrček,
• Rinea Barbir,
• Vedran Micek,
• Raluca M. Fratila,
• Jesus M. de la Fuente and
• Ivana Vinković Vrček

Beilstein J. Nanotechnol. 2021, 12, 665–679, doi:10.3762/bjnano.12.53

• found in PBS and BP incubated with different AgNPs (Figure 4) may, thus, be an indirect evidence of AgCl crystal formation in PBS and BP, which is possible only if the ionic Ag form is released form the AgNP surface by an oxidative etching process. Such release may be accelerated in the presence of

• etching process of AgNPs. The reformation of AgNPs from primary particles or released Ag+ was evidenced by the incubation of AgNO3 in liver and brain homogenates which led to the formation of small AgNPs. Moreover, NMR experiments demonstrated the crucial role of biothiols in this reformation process. Our

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

• –1016 ions/cm2, the rate of subsequent wet-etching of the irradiated regions with hydrofluoric acid was found to increase by up to a factor of three (for Si3N4) and five (for SiO2). The change was attributed to ion-induced defects and demonstrates another potential form of HIM-enabled nanofabrication

• , namely site-specific ion-enhanced etching with high spatial resolution. Similarly, site-selective etching of MoS2 has been demonstrated using helium ion irradiation to create defective regions that become activated for oxygen adsorption and subsequent oxidative etching when heated in air [68]. Helium ion

Impact of GaAs(100) surface preparation on EQE of AZO/Al₂O₃/p-GaAs photovoltaic structures

• Piotr Caban,
• Rafał Pietruszka,
• Jarosław Kaszewski,
• Monika Ożga,
• Bartłomiej S. Witkowski,
• Krzysztof Kopalko,
• Piotr Kuźmiuk,
• Katarzyna Gwóźdź,
• Ewa Płaczek-Popko,
• Krystyna Lawniczak-Jablonska and
• Marek Godlewski

Beilstein J. Nanotechnol. 2021, 12, 578–592, doi:10.3762/bjnano.12.48

• /interface needs to be properly prepared. In the experiments described here we examined eight different paths of GaAs surface treatment (cleaning, etching, passivation) which resulted in different external quantum efficiency (EQE) values of the tested photovoltaic (PV) cells. Atomic force microscopy (AFM

• deposition method is ALD [14][15]. Removal of native oxide layer and protection of such an obtained surface can be done in many ways. In the case of wet-etching techniques, the most popular GaAs native oxide etchants are based on acidic and basic solutions. In order to etch the oxide, one can treat the

• surface with an acidic/base aqueous solution (e.g., HCl/H2O, NH4OH/H2O) [16]. If not only the oxide layer but also the suboxide layer of GaAs need to be etched, different methods can be utilized which combine both processes: semiconductor surface oxidation and etching. In this case, also acidic and basic