Entry of nanoparticles into cells and tissues: status and challenges

• Kirsten Sandvig,
• Tore Geir Iversen and
• Tore Skotland

Beilstein J. Nanotechnol. 2024, 15, 1017–1029, doi:10.3762/bjnano.15.83

• -macroglobulin, EGF, and transferrin, and a concomitant depletion of these receptors at the plasma membrane [46]. One might expect that other receptors that normally recycle after uptake from clathrin-coated pits are also affected in a similar manner, and that NPs targeting such receptors might have a reduced

Elastic modulus of β-Ga₂O₃ nanowires measured by resonance and three-point bending techniques

• Annamarija Trausa,
• Sven Oras,
• Sergei Vlassov,
• Mikk Antsov,
• Tauno Tiirats,
• Andreas Kyritsakis,
• Boris Polyakov and
• Edgars Butanovs

Beilstein J. Nanotechnol. 2024, 15, 704–712, doi:10.3762/bjnano.15.58

• photoresist on the wafer using conventional optical lithography. Next, the SiO2 was selectively removed using a buffered HF solution to replicate the resist pattern in the oxide layer. Then, the silicon was etched at 90 °C in a tetramethylammonium hydroxide (TMAH) solution to create etch pits. Finally, the

Heat-induced morphological changes in silver nanowires deposited on a patterned silicon substrate

• Elyad Damerchi,
• Sven Oras,
• Edgars Butanovs,
• Allar Liivlaid,
• Mikk Antsov,
• Boris Polyakov,
• Annamarija Trausa,
• Veronika Zadin,
• Andreas Kyritsakis,
• Loïc Vidal,
• Karine Mougin,
• Siim Pikker and
• Sergei Vlassov

Beilstein J. Nanotechnol. 2024, 15, 435–446, doi:10.3762/bjnano.15.39

• HF solution in order to replicate the resist pattern in the oxide layer; 3) silicon etching in tetramethylammonium hydroxide (TMAH) solution at 90 °C to create the etch pits; 4) rinse in HF to remove the remaining SiO2. The resulting substrates had rectangular holes with a side length in the order of

Investigating ripple pattern formation and damage profiles in Si and Ge induced by 100 keV Ar⁺ ion beam: a comparative study

• Indra Sulania,
• Harpreet Sondhi,
• Tanuj Kumar,
• Sunil Ojha,
• G R Umapathy,
• Ambuj Mishra,
• Ambuj Tripathi,
• Richa Krishna,
• Devesh Kumar Avasthi and
• Yogendra Kumar Mishra

Beilstein J. Nanotechnol. 2024, 15, 367–375, doi:10.3762/bjnano.15.33

• microscopy (AFM) [3] and transmission electron microscopy (TEM), it is possible to visualize these features. Formation of dots, ripples, and pits have been well studied using IBS [4][5][6][7][8][9]. In the last few decades, numerous efforts have been made to understand IBS through simulations [10] as well as

Enhanced feedback performance in off-resonance AFM modes through pulse train sampling

• Mustafa Kangül,
• Navid Asmari,
• Santiago H. Andany,
• Marcos Penedo and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2024, 15, 134–143, doi:10.3762/bjnano.15.13

• -built tip scanner system to compare their imaging performance. A grid sample (squared pits of 10 μm XY pitch and 200 nm depth) was chosen, since it has sharp topography changes on the pit edges and a small tilting angle on the flat surface, providing both high-frequency and low-frequency disturbances to

• in both measurements were set just below the values that would lead to observable oscillations. Height images in Figure 4A show that the pulse sampling method has better tracking performance for rapid topography changes of the pits. The method provides sharper responses at the pit edges, indicating

Spatial variations of conductivity of self-assembled monolayers of dodecanethiol on Au/mica and Au/Si substrates

• Julian Skolaut,
• Jędrzej Tepper,
• Federica Galli,
• Wulf Wulfhekel and
• Jan M. van Ruitenbeek

Beilstein J. Nanotechnol. 2023, 14, 1169–1177, doi:10.3762/bjnano.14.97

• observable. Second, dark spots on the terraces of the current map appear, which can be seen clearly in the expanded-scale image in Figure 3d. These can be attributed to so-called etch pits that arise from the growth of sulfur-bound SAMs on Au surfaces [19][20]. These etch pits are monatomically deep holes in

• File 1. The etch pits serve as evidence that the SAMs form in an ordered fashion. The abovementioned features can also be seen clearly in the 3D view of the surface in Figure 3c, where the color coding indicates the measured current at each point. The 3D view also underlines the direct correspondence

• the same area, the center square of the image appears lower in topography compared to the sides when the scanning area is widened. Also, the measured current increases from image to image, while the etch pits remain intact, indicating that the Au surface structure remains unaffected. We attribute

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

• , in turn, can promote surface mobility of gold across a sample, allowing for the formation of herringbone structures, pits, and step edges [23][24][25]. Other work has shown that tetrahydrofuran (THF), an organic solvent used for SAM formation [1][2][4][6][7][8], can roughen the gold surface at atomic

Biomimetics on the micro- and nanoscale – The 25th anniversary of the lotus effect

• Matthias Mail,
• Kerstin Koch,
• Thomas Speck,
• William M. Megill and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2023, 14, 850–856, doi:10.3762/bjnano.14.69

• processes by the authors. They looked to a seemingly unrelated archetype, the xylem system of trees, which uses pits instead of extrusions to create its surface properties. This led the team to a new approach and eventually to a successful product. The authors present the case study as a reminder that the

SERS performance of GaN/Ag substrates fabricated by Ag coating of GaN platforms

• Magdalena A. Zając,
• Bogusław Budner,
• Malwina Liszewska,
• Bartosz Bartosewicz,
• Łukasz Gutowski,
• Jan L. Weyher and
• Bartłomiej J. Jankiewicz

Beilstein J. Nanotechnol. 2023, 14, 552–564, doi:10.3762/bjnano.14.46

• plasmonic metals or their alloys [23][24][25][26][27][28][29][30][31][32]. The chemical and electrochemical etching of GaN heteroepitaxial layers leads to various nanostructures formed on line defects (dislocations), such as straight nanopillars, bunches of nanopillars, and pits [31][32]. The nanostructured

Straight roads into nowhere – obvious and not-so-obvious biological models for ferrophobic surfaces

• Wilfried Konrad,
• Christoph Neinhuis and
• Anita Roth-Nebelsick

Beilstein J. Nanotechnol. 2022, 13, 1345–1360, doi:10.3762/bjnano.13.111

• furnace; Collembola; gas/liquid interfaces; interfacial effects; persistant air layers; pits; Salvinia molesta; surfaces; tuyère failure; water transport in plants; xylem; Young–Laplace equation; Introduction and Motivation The basic concept of biomimetics is the derivation of technical applications from

• molecules flowing inside them are connected to each other and to the conduit walls by cohesion generated by van der Waals forces. The conduits are interconnected by pores, termed “pits”, which allow water to enter and leave the conduits on the way upwards (see Figure 4). In this way, a three-dimensional

• isolating the pit membrane from water (see appendix C). Various research was dedicated to this putative mechanism. Studies contributed by Konrad and Roth-Nebelsick [44][45], who considered the interfacial physics of the proposed mechanism, provided evidence that such an interface may be possible within pits

Relationship between corrosion and nanoscale friction on a metallic glass

• Haoran Ma and
• Roland Bennewitz

Beilstein J. Nanotechnol. 2022, 13, 236–244, doi:10.3762/bjnano.13.18

• scanning electron microscopy (SEM); the images are shown in Figure 1b,c. Corrosion pits with a lateral extension of tens of micrometers were observed on the surface polarized in NaCl solution, indicating that the chloride-containing solution initiates localized pitting. The inset in Figure 1b shows the

• magnified image of typical corrosion pits. No such pits are found after polarization in phosphate buffer (Figure 1c). The surface is mostly smooth and only some parts exhibit signs of increased roughness (inset in Figure 1c). We conclude that the polarization-induced surface modifications proceed uniformly

• copper surfaces, where it was suggested that more electrons escape in the vicinity of a peak than in a valley [27]. A surface undulation with parallel valleys on our ZrNiTi MG ribbons may be the reason for the distribution of pits along lines. Another possible reason is residual stress, indicated by the

Two dynamic modes to streamline challenging atomic force microscopy measurements

• Alexei G. Temiryazev,
• Andrey V. Krayev and
• Marina P. Temiryazeva

Beilstein J. Nanotechnol. 2021, 12, 1226–1236, doi:10.3762/bjnano.12.90

• , pits (or protrusions) of about 1.5–2.5 nm height will appear in the obtained image of the surface. It is very important to select scanning parameters that guarantee the operation away from this region of bistability. The choice of a good value of p depends on the initial amplitude A0 and the tip

• oscillation amplitude still exceeds A1, we will write down all the necessary parameters and start moving to the next point. This allows us to continue scanning even if we cannot reach the bottom surface in the case of tall objects or samples with deep pits. Conversely, if at the top level Htop the oscillation

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

• pits. The self-organization of structures was attributed to tin chloride, which led to a larger size of the pits, while copper oxide led to the formation of hillocks in the film. The D values of the samples were in the range of 2.00–2.24. For the Sn/Cu = 6 ratio, the fractal dimension was 2.0, and the

Influence of electrospray deposition on C₆₀ molecular assemblies

• Antoine Hinaut,
• Sebastian Scherb,
• Sara Freund,
• Zhao Liu,
• Thilo Glatzel and
• Ernst Meyer

Beilstein J. Nanotechnol. 2021, 12, 552–558, doi:10.3762/bjnano.12.45

• cluster of Figure 3d. The number of layers ranges from one to at least five. Moreover, the islands present a more rounded shape, compared to TE islands, and no direction favored by the sixfold symmetry is observed. The influence of HV-ESD on the surface itself can also be seen. First, monolayer-deep pits

• are visible, see the arrow in the contrast-modified inset of Figure 3c and in part 3 of Supporting Information File 1. They are similar to the pits created after electron and ion bombardment [40][41][42][43] or low-temperature plasma exposure of such a surface [44]. Such defects are known to increase

The impact of molecular tumor profiling on the design strategies for targeting myeloid leukemia and EGFR/CD44-positive solid tumors

• Nikola Geskovski,
• Nadica Matevska-Geshkovska,
• Simona Dimchevska Sazdovska,
• Marija Glavas Dodov,
• Kristina Mladenovska and
• Katerina Goracinova

Beilstein J. Nanotechnol. 2021, 12, 375–401, doi:10.3762/bjnano.12.31

• solutes and even particulate matter [18]. Portions of the sinusoidal endothelial cells could be noticeably reduced into small fenestrae with sizes in the range of 80–150 nm, which could facilitate the paracellular MBB transport. On the other hand, their clathrin-coated pits, lysosomes, clathrin-coated

Differences in surface chemistry of iron oxide nanoparticles result in different routes of internalization

• Barbora Svitkova,
• Vlasta Zavisova,
• Veronika Nemethova,
• Martina Koneracka,
• Miroslava Kretova,
• Filip Razga,
• Monika Ursinyova and
• Alena Gabelova

Beilstein J. Nanotechnol. 2021, 12, 270–281, doi:10.3762/bjnano.12.22

• of cellular entry. Caveolae are characteristic flask-shaped membrane invaginations with an average size of 50–100 nm [12], lined by caveolin and enriched with cholesterol and sphingolipids. The deeply invaginated clathrin or caveolin pits are then fissured from the membrane by GTPase dynamin

• F was higher than that of N. Interestingly, MBCD could neither inhibit the cellular internalization of Tr nor that of ChT. Application of Dyn resulted in the accumulation of Tr as well as that of ChT in larger spots, probably in the clathrin-coated pits/caveolae at the inner side of the membrane

• Dyn, the signal of RITC-BSA-SO-MNPs and FITC–clathrin was co-localized on the cell membrane (yellow signal), indicating the accumulation of a fraction of nanoparticles in the clathrin-coated pits (Figure 3D). The pattern of the co-localization signal of RITC-BSA-SO-MNPs and FITC–clathrin implied that

Bio-imaging with the helium-ion microscope: A review

• Matthias Schmidt,
• James M. Byrne and
• Ilari J. Maasilta

Beilstein J. Nanotechnol. 2021, 12, 1–23, doi:10.3762/bjnano.12.1

• tetroxide-fixed, uncoated, and critical-point-dried human neurons and mouse hippocampal neurons. The achieved lateral resolution of 1.5 nm allowed for visualising pits in the ultrastructure of the cell membranes. Based on that finding the authors hypothesised “that the pit-like domains are a direct

• visualization of the shape of membrane nanodomains, including lipid rafts and caveolae.” It was concluded that the pits result from the sample preparation since “the cell fixation with OsO4 cross-links the lipid bilayer outside the nanodomains while the lipid bilayer inside the nanodomains is removed by the

• required subsequent rinsing with ethanol for the cell drying process.” In turn, the pits in the HIM image reveal “the shape of the nanodomains as missing lipid bilayers.” In 2018, HIM was used to study peptide nanostructures for the first time. Herrera et al. studied the initial stages of the

Fabrication of nano/microstructures for SERS substrates using an electrochemical method

• Jingran Zhang,
• Tianqi Jia,
• Xiaoping Li,
• Junjie Yang,
• Zhengkai Li,
• Guangfeng Shi,
• Xinming Zhang and
• Zuobin Wang

Beilstein J. Nanotechnol. 2020, 11, 1568–1576, doi:10.3762/bjnano.11.139

• lithography (EBL) and wet etching consists of 1 μm deep square-based pyramidal pits in the silicon surface. A rhodamine solution (10−4 mol·L−1) is then detected using the Klarite substrate. Candeloro et al. [24] employed EBL and reactive ion etching to machine nanoholes of 400 nm diameter and 50 nm depth

Applications of superparamagnetic iron oxide nanoparticles in drug and therapeutic delivery, and biotechnological advancements

• Maria Suciu,
• Corina M. Ionescu,
• Alexandra Ciorita,
• Septimiu C. Tripon,
• Dragos Nica,
• Hani Al-Salami and
• Lucian Barbu-Tudoran

Beilstein J. Nanotechnol. 2020, 11, 1092–1109, doi:10.3762/bjnano.11.94

• clathrin and/or caveolae pits, RhoA, CDC42, ARF6, or flotillin-mediated endocytosis/phagocytosis and receptor-independent macro- and micropinocytosis (for reviews on the endocytosis of nanoparticles see [105][106]). Macropinocytosis is not selective and can take up spheres with a diameter of up to 1 mm [81

Key for crossing the BBB with nanoparticles: the rational design

• Sonia M. Lombardo,
• Marc Schneider,
• Akif E. Türeli and
• Nazende Günday Türeli

Beilstein J. Nanotechnol. 2020, 11, 866–883, doi:10.3762/bjnano.11.72

• endocytic vesicles have been identified and described in the brain endothelial cells: clathrin-coated pits, caveolae and macropinocytosis vesicles. Clathrin-coated pits are involved in most of the internalization processes mediated by receptors such as TfR or insulin receptors [39][40]. After endocytosis

Formation of nanoripples on ZnO flat substrates and nanorods by gas cluster ion bombardment

• Xiaomei Zeng,
• Vasiliy Pelenovich,
• Bin Xing,
• Rakhim Rakhimov,
• Wenbin Zuo,
• Alexander Tolstogouzov,
• Chuansheng Liu,
• Dejun Fu and
• Xiangheng Xiao

Beilstein J. Nanotechnol. 2020, 11, 383–390, doi:10.3762/bjnano.11.29

• and ion fluence were 10 kV and 4 × 1016 clusters/cm2, respectively. Scratches and pits of 50–100 nm in size and 5 nm in depth are visible on the substrate surface before irradiation (Figure 2a and Figure 3a). After irradiation at θ = 0° the scratches and pits disappeared and features ca. 10 nm in size

• are formed (Figure 2f). These grooves represent the pits and scratches on the initial surface modified by the cluster beam bombardment. The shape of the grooves is similar to those formed on a gold surface irradiated by the GCIB at 70° [19]. The absence of visible ripple morphology in this case can be

Interactions at the cell membrane and pathways of internalization of nano-sized materials for nanomedicine

• Valentina Francia,
• Daphne Montizaan and
• Anna Salvati

Beilstein J. Nanotechnol. 2020, 11, 338–353, doi:10.3762/bjnano.11.25

• the size of clathrin-coated pits enter through clathrin-mediated endocytosis [115][124] and, vice versa, that larger ones do not. It was thought that the geometry and 3D structure of clathrin would not allow it. However, results opposing this general idea about size have also been reported [116][125

• PRINT particles was reduced by chlorpromazine (an inhibitor of clathrin-dependent endocytosis) [125] and it has been shown that larger particles could be internalized in pits coated with plaques of clathrin [128][129][130]. These studies, selected just as examples among many others, already highlight

Internalization mechanisms of cell-penetrating peptides

• Ivana Ruseska and
• Andreas Zimmer

Beilstein J. Nanotechnol. 2020, 11, 101–123, doi:10.3762/bjnano.11.10

• coated pit that adopts the shape of a spherical membrane structure with a diameter of 100–150 nm. Shallow pits undergo progressive invagination into dome-like shapes, which are connected to the plasma membrane by a funnel-like rim. Further invagination leads to the formation of a spherical bud, and the

Integration of sharp silicon nitride tips into high-speed SU8 cantilevers in a batch fabrication process

• Nahid Hosseini,
• Matthias Neuenschwander,
• Oliver Peric,
• Santiago H. Andany,
• Jonathan D. Adams and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2019, 10, 2357–2363, doi:10.3762/bjnano.10.226

• pits. The diameter of the circular openings defines the final height of the tips and can be tuned. (ii) The LSNT mask is removed in HF 50%. Afterwards, a 400 nm wet silicon oxide layer and a 100 nm LSNT layer are deposited on the wafer. The 400 nm silicon oxide layer improves the tip sharpness by

• silicon oxide and the LSNT layers are patterned by photolithography to cover only the etched pits. (iv) Deep reactive ion etching (DRIE) is used to etch the silicon vertically and laterally (4 and 1 µm, respectively) in order to provide access for the SU8 polymer to fill the base of the tips in the

Geometrical optimisation of core–shell nanowire arrays for enhanced absorption in thin crystalline silicon heterojunction solar cells

• Robin Vismara,
• Olindo Isabella,
• Andrea Ingenito,
• Fai Tong Si and
• Miro Zeman

Beilstein J. Nanotechnol. 2019, 10, 322–331, doi:10.3762/bjnano.10.31

• of SiOxFy particles, which start the formation of randomly distributed etch pits [42]. These regions become deeper during the process, thanks to the strong anisotropic nature of this RIE etching. A back-side emitter was formed by phosphorous ion implantation, with energy of 2 × 1015 cm−2 and dose of