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

• adjust settings such as slicing, shell and scaffolding, laser power, and scanning speeds before converting to General Writing Language (GWL) codes. Parameters such as slicing distance of 2 µm, multiple base slide counts of 4 layers, shell and scaffolding filling method, null shear angle (0°), and laser

• which results in lateral shear loads. This horizontal shear force component () that is perpendicular to the axis of each MN may cause fracture at an approximate distance x from the base where the yield stress of the material is exceeded. Therefore, for MNs having a cylindrical shaft of radius a, with

• horizontal shear stress forces, and buckling failure, which occurred at the axial applied force of 1.29 N. Figure 5b illustrates the experimental force-displacement diagram for the theoretical prediction of the moment of critical buckling load. The peak on the graph indicated the MN failure. However, due to

Quantitative dynamic force microscopy with inclined tip oscillation

• Philipp Rahe,
• Daniel Heile,
• Reinhard Olbrich and
• Michael Reichling

Beilstein J. Nanotechnol. 2022, 13, 610–619, doi:10.3762/bjnano.13.53

• for the investigation of in-plane material properties, such as the in-plane shear modulus [16]. Last, the influence of the inclination between oscillation direction and surface plane has been used in lateral force microscopy to determine the probe oscillation amplitude [17]. Here, we extend the

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

• factors, but also provides a suitable mechanical environment for cells, including physical signals such as substrate stiffness, hydrostatic pressure, shear stress, strain, pressure, and tension [7][8][9]. These mechanical factors play an important role in regulating normal cellular physiological functions

Micro- and nanotechnology in biomedical engineering for cartilage tissue regeneration in osteoarthritis

• Zahra Nabizadeh,
• Mahmoud Nasrollahzadeh,
• Hamed Daemi,
• Mohamadreza Baghaban Eslaminejad,
• Ali Akbar Shabani,
• Mehdi Dadashpour,
• Majid Mirmohammadkhani and
• Davood Nasrabadi

Beilstein J. Nanotechnol. 2022, 13, 363–389, doi:10.3762/bjnano.13.31

• supports deeper layers from shear stresses [5]. The middle or transitional zone constitutes the thickest portion of articular cartilage (40–60%) and has fewer chondrocytes with a more rounded morphology [6]. In this layer, the collagen fibrils are arranged randomly and obliquely and the cells synthesize

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

• , pitting is always distributed along a line. Wang et al. [26] found that pitting occurs preferentially at the shear offsets on a pre-deformed Zr-based MG due to the higher chemical activity of offset sites compared with the surrounding flat region. This influence of surface morphology was also shown for

• area of the inner layer and tip apex at a higher normal load [34][35]. The friction force of the outer layer reveals the lateral plowing resistance of the outer layer to the sliding tip, which must depend on the shear strength of the layer and its structure. The friction data for each respective load

• immersion time due to the development of defects in the surface film [40][41]. The increase in the friction coefficient of the outer layer indicates the growth of the outer layer with increasing immersion time. More material of possibly higher shear strength is in contact with the sliding tip, which

Theoretical understanding of electronic and mechanical properties of 1T′ transition metal dichalcogenide crystals

• Seyedeh Alieh Kazemi,
• Sadegh Imani Yengejeh,
• Vei Wang,
• William Wen and
• Yun Wang

Beilstein J. Nanotechnol. 2022, 13, 160–171, doi:10.3762/bjnano.13.11

• ′ polytype; anisotropy; density functional theory; layered transition metal dichalcogenide crystals; shear modulus; Young’s modulus; Introduction Layered transition metal dichalcogenides (TMDs) have received increasing attention as important and versatile materials for new applications in different sectors

• TMDs, the properties of which are more similar to those of TMD crystals, have also been widely used in engineering and practical applications [7][21][28][29]. Moreover, shear modes and interlayer breathing of bulk TMDs are crucial parameters regarding their mechanical characteristics and directly

• ability to predict the mechanical characteristics of 1T′ TMD materials [33]. In this comparative study, the electronic and mechanical properties including shear modulus (G), bulk modulus (B), Young’s modulus (Y), Poisson’s ratio (ν), and microhardness (H), of MoS2, MoSe2, WS2, and WSe2 crystals with the

Effect of lubricants on the rotational transmission between solid-state gears

• Huang-Hsiang Lin,
• Jonathan Heinze,
• Alexander Croy,
• Rafael Gutiérrez and
• Gianaurelio Cuniberti

Beilstein J. Nanotechnol. 2022, 13, 54–62, doi:10.3762/bjnano.13.3

• fluid. One obtains several fluid properties such as pressure, velocity, shear stress, density and strain rate. In the case of the gear–oil–gear system, several studies based on the CFD simulation have been reported [11][12][13][14][15][16][17][18]. However, most of the simulations for this type of

• account by, for example, Lennard-Jones potentials [50]. Several works based on MD simulations were performed to study the shear viscosity in either bulk lubricants [51][52][53] or lubricants confined by two surfaces [54][55]. However, to date, MD simulations for the gear–lubricant–gear case are still

A review on slip boundary conditions at the nanoscale: recent development and applications

• Ruifei Wang,
• Jin Chai,
• Bobo Luo,
• Xiong Liu,
• Jianting Zhang,
• Min Wu,
• Mingdan Wei and
• Zhuanyue Ma

Beilstein J. Nanotechnol. 2021, 12, 1237–1251, doi:10.3762/bjnano.12.91

• other properties with a high resolution [43]. Finally, when the flow systems are under extreme conditions, such as at high shear rates, it has also been proven that numerical simulations are more efficient than experimental methods [45]. Therefore, in this review we mainly focus on the numerical

• zero (see Figure 1a). The relationship between slip length b and liquid slip velocity νs at the surface can be expressed as follows: where ν is liquid velocity and h is the channel height. When the liquid is at equilibrium, the viscous shear stress is exerted by the liquid on the wall, where η is the

• shear viscosity of the liquid, equal to the friction stress suffered by the liquid from the wall, which is expressed as σ = λνs, where λ represents the interfacial friction coefficient [46]. Therefore, the slip length can be expressed as , which indicates that the slip length is reduced with the

Effects of temperature and repeat layer spacing on mechanical properties of graphene/polycrystalline copper nanolaminated composites under shear loading

• Chia-Wei Huang,
• Man-Ping Chang and
• Te-Hua Fang

Beilstein J. Nanotechnol. 2021, 12, 863–877, doi:10.3762/bjnano.12.65

• ) composites under shear loading are investigated by molecular dynamics simulations. The effects of different temperatures, graphene chirality, repeat layer spacing, and grain size on the mechanical properties, such as failure mechanism, dislocation, and shear modulus, are observed. The results indicate that

• as the temperature increases, the content of Shockley dislocations will increase and the maximum shear stress of the zigzag and armchair directions also decreases. The mechanical strength of the zigzag direction is more dependent on the temperature than that of the armchair direction. Moreover, self

• -healing occurs in the armchair direction, which causes the shear stress to increase after failure. Furthermore, the maximum shear stress and the shear strength of the composites decrease with an increase of the repeat layer spacing. Also, the shear modulus increases by increasing the grain size of copper

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

• the MBs, leading to the term “microstream”. Depending on the US intensity, the oscillating MBs come into close proximity with the cells and induce stresses on the cell membrane [75]. Consequently, the triggered shear forces cause disruption of the cell membrane and increase intracellular uptake of

• . reported that when the distance between the cell and the MB was increased to 5.5 µm, the exerted shear stress on the cell membrane suddenly decreased [78]. Schlicher et al. exposed prostate cancer cells (DU145) to 24 kHz US irradiation to investigate the cavitation events and the changes in the cell

Physical constraints lead to parallel evolution of micro- and nanostructures of animal adhesive pads: a review

• Thies H. Büscher and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2021, 12, 725–743, doi:10.3762/bjnano.12.57

• recruited in this case. Such a mechanism may secure a stable position of an animal on a ceiling. As the shear forces are applied proximally towards the body in this situation, and because of a stronger friction in this direction due to an intimate contact between the membranes/spatulae, the pad sliding can

Spontaneous shape transition of Mn_xGe_1−x islands to long nanowires

• S. Javad Rezvani,
• Luc Favre,
• Gabriele Giuli,
• Yiming Wubulikasimu,
• Isabelle Berbezier,
• Augusto Marcelli,
• Luca Boarino and
• Nicola Pinto

Beilstein J. Nanotechnol. 2021, 12, 366–374, doi:10.3762/bjnano.12.30

• plane, the Poisson ratio, and the shear modulus of the substrate, respectively [34]. The value of Γ/ch controls the final distribution and size of the islands. In particular, if Γ/ch ≫ 1, then α0 becomes too large to reduce the edge-to-area ratio. While the mechanism described here applies to the

Determination of elastic moduli of elastic–plastic microspherical materials using nanoindentation simulation without mechanical polishing

• Hongzhou Li and
• Jialian Chen

Beilstein J. Nanotechnol. 2021, 12, 213–221, doi:10.3762/bjnano.12.17

• of an elastic half space by a flat, cylindrical punch leads to a simple relation between P and h of the form [27] where a is the radius of the cylinder and G is the shear modulus. Noting that the contact area (i.e., the projected area or cross-sectional area of elastic contact) A is equal to πa2 and

• that the shear modulus is equal to E/[2(1 + ν)], differentiating P with respect to h leads to where S = dP/dh is the initial stiffness of the unloading curve, defined as the slope of the upper portion of the unloading curve during the initial stages of unloading (also called contact stiffness), and E

A review on the green and sustainable synthesis of silver nanoparticles and one-dimensional silver nanostructures

• Sina Kaabipour and
• Shohreh Hemmati

Beilstein J. Nanotechnol. 2021, 12, 102–136, doi:10.3762/bjnano.12.9

• in sheet resistance and to increase touch sensitivity [89]. Furthermore, AgNWs can be used to prepare AgNW-based conductive inks that have remarkable rheological characteristics such as thixotropic shear thinning and thus, can be simply used for screen printing without the addition of polymeric

Design of V-shaped cantilevers for enhanced multifrequency AFM measurements

• Mehrnoosh Damircheli and
• Babak Eslami

Beilstein J. Nanotechnol. 2020, 11, 1525–1541, doi:10.3762/bjnano.11.135

• , y(x,t), ϕ(x,t), ρ, I, E and c are shear coefficient, shear modulus, area of cross section, transverse deflection of the beam, bending angle of the beam, mass density of the beam, moment of inertia of cross section, Young’s modulus, and internal damping of the cantilevers, respectively. The cross

On the frequency dependence of viscoelastic material characterization with intermittent-contact dynamic atomic force microscopy: avoiding mischaracterization across large frequency ranges

• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 1409–1418, doi:10.3762/bjnano.11.125

• viscoelastic harmonic functions as a function of frequency in the range of frequencies involved in the experiment. For example, for the Generalized Maxwell model, which this paper focuses on, the storage shear modulus, G′, which accounts for the elastic behavior of the material under harmonic excitation, is

• given by [15]: where ω is the angular frequency, equal to 2πν. At zero frequency, G′, is equal to Ge, the rubbery shear modulus, and as the frequency increases, it converges to the glassy shear modulus, Gg, which is given by: The loss shear modulus, G″, which accounts for the viscous behavior of the

• material, is given by [15]: where G″(ω) at both zero and infinitely large frequencies converges to zero, implying pure elastic behavior at those extrema. Note that the above equations and paragraphs refer to shear moduli (e.g., storage shear modulus and loss shear modulus) instead of tensile (Young´s

Magnetohydrodynamic stagnation point on a Casson nanofluid flow over a radially stretching sheet

• Ganji Narender,
• Kamatam Govardhan and
• Gobburu Sreedhar Sarma

Beilstein J. Nanotechnol. 2020, 11, 1303–1315, doi:10.3762/bjnano.11.114

• fluid can be considered as a shear-thinning liquid, with infinite viscosity. On the other hand, when the stress rate approaches an infinite value the viscosity of the Casson fluid drops to zero [6]. Jam, tomato ketchup, honey, and concentrated fruit syrups are some quotidian examples of Casson fluids

An atomic force microscope integrated with a helium ion microscope for correlative nanoscale characterization

• Santiago H. Andany,
• Gregor Hlawacek,
• Stefan Hummel,
• Charlène Brillard,
• Mustafa Kangül and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2020, 11, 1272–1279, doi:10.3762/bjnano.11.111

• down the sample using the z-piezo of the scanner, causing intermittent contact between the cantilever and the sample [25]. The maximum interaction force is computed and used as feedback by the controller, providing fine force control, reducing shear forces and thus preserving the tip and the sample [26

Magnetic-field-assisted synthesis of anisotropic iron oxide particles: Effect of pH

• Andrey V. Shibaev,
• Petr V. Shvets,
• Darya E. Kessel,
• Roman A. Kamyshinsky,
• Anton S. Orekhov,
• Sergey S. Abramchuk,
• Alexei R. Khokhlov and
• Olga E. Philippova

Beilstein J. Nanotechnol. 2020, 11, 1230–1241, doi:10.3762/bjnano.11.107

• ] in the presence of shear [40], etc. Almost all of these methods involve either the use of a template or a stabilizing agent to induce a directional one-dimensional growth of rod-like nanoparticles. The most common agents used are surfactants [11][21][23][26][37], polymers [27][36] and other additives

Revealing the local crystallinity of single silicon core–shell nanowires using tip-enhanced Raman spectroscopy

• Marius van den Berg,
• Ardeshir Moeinian,
• Arne Kobald,
• Yu-Ting Chen,
• Anke Horneber,
• Steffen Strehle,
• Alfred J. Meixner and
• Dai Zhang

Beilstein J. Nanotechnol. 2020, 11, 1147–1156, doi:10.3762/bjnano.11.99

• ) along the perimeter of a SiNW. The tip–sample distance is controlled by a shear-force feedback. For this purpose, the tip is mounted on an oscillating tuning fork, which experiences a phase shift of the oscillation upon approach. This phase shift is recorded with a lock-in amplifier and fed to a

• measured using the shear-force scanning function of our custom-built TERS setup. Eight TERS spectra were taken along the white arrow in Figure 5a over a length of 64 nm. The distance between the two sequential spectra is 8 nm. The spectra were acquired from bottom to top, with the black spectrum on the

• observed. a) A shear-force scanning probe microscopy topography image (250 × 250 nm2) of a silicon wire edge. The white arrow indicates the range and direction along which the Raman spectra in panels c and d were recorded. b) Location of the wire indicated on the 50 × 50 µm2 optical image by a white square

Vibration analysis and pull-in instability behavior in a multiwalled piezoelectric nanosensor with fluid flow conveyance

• Sayyid H. Hashemi Kachapi

Beilstein J. Nanotechnol. 2020, 11, 1072–1081, doi:10.3762/bjnano.11.92

• piezoelectric doubly curved nanoshells and orthotropic piezoelectric cylindrical nanoshells [23][24]. Wang utilized surface strain gradient elasticity to study a meticulous solution to the anti-plane shear problem of a circular elastic inhomogeneity [25]. Nami et al. utilized nonlocal elasticity theory and

• trigonometric shear deformation theory to investigate the static analysis of rectangular nanoplates [26]. The Gurtin–Murdoch surface theory is presented by Sigaeva et al. to study the universal model describing plane strain bending of a multilayered sector of a cylindrical tube [27]. Karimipour et al. presented

Wet-spinning of magneto-responsive helical chitosan microfibers

• Dorothea Brüggemann,
• Johanna Michel,
• Naiana Suter,
• Matheus Grande de Aguiar and
• Michael Maas

Beilstein J. Nanotechnol. 2020, 11, 991–999, doi:10.3762/bjnano.11.83

• helical fibers have the potential to be used as novel actuator systems or as magneto-responsive scaffolds for tissue engineering. Results and Discussion The viscous feedstock solutions containing 30 mg·mL−1 chitosan and 10 mg·mL−1 magnetic iron oxide particles (IOPs) showed a pronounced shear-thinning

• behavior. These results were corroborated by previous studies that used aqueous chitosan solutions for wet-spinning experiments [28][50]. A zero-shear viscosity of approximately 10 Pa·s (Figure 1A) was obtained. The yield point was not strongly pronounced at 0.1 Pa (Figure 1B), which explains why further

• rheometer (Malvern, Herrenberg, Germany) with a cone-plate geometry (1° angle and 50 mm diameter). The shear stress was measured at 20 °C with a stepwise increase in the shear rate and a one minute holding time at each shear-rate step. The size and zeta potential measurements were performed with 10 mg·mL−1

Extracting viscoelastic material parameters using an atomic force microscope and static force spectroscopy

• Cameron H. Parvini,
• M. A. S. R. Saadi and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 922–937, doi:10.3762/bjnano.11.77

• very stiff will have a high storage modulus and a low loss modulus. Such a sample will tend to store a majority of the applied load within its molecular structure and elastically return most or all of that energy when unloaded. Alternately, a medium that is susceptible to large shear forces (such as

Identification of physicochemical properties that modulate nanoparticle aggregation in blood

• Ludovica Soddu,
• Duong N. Trinh,
• Eimear Dunne,
• Dermot Kenny,
• Giorgia Bernardini,
• Ida Kokalari,
• Arianna Marucco,
• Marco P. Monopoli and
• Ivana Fenoglio

Beilstein J. Nanotechnol. 2020, 11, 550–567, doi:10.3762/bjnano.11.44

• . Dynamic platelet function assay (DPFA) The DPFA is a well-characterised real-time assay of platelet interaction with von Willebrand factor (VWF) under conditions of arterial shear [27][28][29]. The initial phases of platelet aggregation were assayed using the DPFA as previously described [25][26]. Briefly

• chamber at an arterial rate of shear (1500 s−1). Platelet translocation behaviour was recorded using real-time video microscopy at a rate of 19 frames per second. Image stacks were analysed by a custom-designed and validated software package [27]. The assay measurements obtained from this analysis include

• function assay (DPFA) was then used to investigate possible interference of the NPs on this process. This well-characterised assay monitors shear-mediated dynamic platelet interactions with surface-immobilised VWF. Adhesion was measured as the total number of platelets adhering to the substrate (Figure 11

Multilayer capsules made of weak polyelectrolytes: a review on the preparation, functionalization and applications in drug delivery

• Varsha Sharma and
• Anandhakumar Sundaramurthy

Beilstein J. Nanotechnol. 2020, 11, 508–532, doi:10.3762/bjnano.11.41