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

• vascular endothelium with tight junctions hampering the permeation of active ingredients to the intraocular area. When designing non-invasive ophthalmic drug dosage forms, the main aim is to improve the bioavailability by increasing the diffusion across sclera, cornea, and conjunctiva [42]. In the case of

• advantage of soluble inserts is that they do not have to be removed from the eye. The rate of drug release is influenced by dissolution or erosion of the polymer matrix. Ophthalmic therapeutic systems belong to the group of non-biodegradable inserts from which the drug substance is released by diffusion at

• microneedles containing an empty canal inside are usually filled with active ingredient solution, either passively or with the use of pressure-driven methods [161]. In the systems using passive diffusion, the drug solution can be loaded to the canals inside the microneedles [141] or to an external compartment

Recent advances in green carbon dots (2015–2022): synthesis, metal ion sensing, and biological applications

• Aisha Kanwal,
• Naheed Bibi,
• Sajjad Hyder,
• Arif Muhammad,
• Hao Ren,
• Jiangtao Liu and
• Zhongli Lei

Beilstein J. Nanotechnol. 2022, 13, 1068–1107, doi:10.3762/bjnano.13.93

• had surface groups such as carboxyl and hydroxy groups. Aloe vera has intrinsic antimicrobial properties, so the bactericidal activity of these CDs was investigated by the agar well diffusion method, and the sensing ability towards Fe3+ was also reported [67]. Kavitha et al. used date palm fronds with

• honey, garlic, and ammonia as green source, sulfur source, and nitrogen source, respectively to prepare N,S-CDs via a simple hydrothermal technique. The Z-scan methodology was used for non-linear optical characterization and the agar well diffusion methodology was used to explore the antimicrobial

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

• potential, and diffusion limiting current density (JL). ACC-2 has the highest positive onset potential of the electrocatalysts. The decreasing order of onset potential is ACC-2 (0.94 V) > ACC-3 (0.92 V) > ACC-1 (0.91 V) > Ag-Co3O4 (0.90 V) > Ag-CuO (0.86 V) > ACC-2* (0.85 V). The kinetics of all trimetallic

• sharp slope in the low-frequency region, representing little ionic diffusion resistance from the 0.1 M KOH solution to the Ag electrode surface throughout the ORR process (Figure 4d). The excellent electrocatalytic ORR activity of ACC-2 may originate from the composition and synergistic effects of

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

• common, but often undesirable occurrence on surfaces irradiated with EB [22][23]. In high-vacuum conditions, hydrocarbons tend to get adsorbed onto the surfaces of vacuum chamber or samples, where they can move via thermally activated diffusion. Cooling the surface can immobilize any adsorbed molecules

• chamber, the growth rate of the nanostructures was cut by about a half and slowly recovered over time, as hydrocarbon concentrations returned to normal levels. The results from Figure 7 support the theory about EB-induced carbon diffusion within the metal substrate and may provide hints of the carbon

• 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

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 the clean sample, the amorphization depth linearly evolves until the implanted argon atoms reach a saturation concentration due to the diffusion and desorption of excess atoms. In the contaminated sample, the observations are similar for argon and for the contaminants, and hydrogen is implanted

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

• be used to generate self-assembled membranes, allowing for the adhesion of endothelial cells on the one side and smooth muscle cells on the other side, as well as the diffusion of relevant molecules, making this material promising for vascular tissue engineering [170]. In addition to flat films or

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

• measurements and for modeling by ab initio calculations. Periodic and compact films are generally obtained when the molecules possess enough surface mobility, that is, when the diffusion energy (Ed) is low compared to the thermal energy kBT, where T is the substrate temperature and kB is the Boltzmann constant

• directly on either the Fe(001) or Fe(001)–p(1 × 1)O surfaces. In the former case, the diffusion of C60 is completely hindered and fullerene forms a disordered film, while in the latter case a peculiar mode of growth, intermediate between diffusion-mediated and ballistic growth, is observed [23][50]. Figure

• promotes the surface diffusion of C60 and the growth of a crystalline film at room temperature. The large HOMO–LUMO gap and the negligible charge transfer at the interface indicate that C60 is electronically decoupled from the substrate. The C60/ZnTPP/Fe(001)–p(1 × 1)O multilayer represents a paradigmatic

Ultrafast signatures of magnetic inhomogeneity in Pd_1−xFe_x (x ≤ 0.08) epitaxial thin films

• Andrey V. Petrov,
• Sergey I. Nikitin,
• Lenar R. Tagirov,
• Amir I. Gumarov,
• Igor V. Yanilkin and
• Roman V. Yusupov

Beilstein J. Nanotechnol. 2022, 13, 836–844, doi:10.3762/bjnano.13.74

• with large (tens of nanometer) layer thicknesses [40][44][45]. It is our hypothesis that itinerant electron spin diffusion could bring the PM areas into equilibrium with the FM environment and is an origin of the 10 ps transient. Indeed, the diffusion velocity across the length of ≈1 nm on a time scale

• of 10 ps can be estimated as 10−9 m/10−11 s = 100 m/s. For the conventional spin diffusion, the spin memory length is where is the diffusion coefficient, τs is the Elliott–Yafet spin-relaxation time [46][47], τ is the charge transport relaxation time, and vF is the Fermi velocity. For the purpose

• of order-of-magnitude estimation we define the spin-diffusion velocity vs as from which Modern band-structure calculations [48][49] show that more than 95% of the electron density of states at the Fermi energy comes from the itinerant 4d electrons. The Fermi velocity of 3d electrons in iron-group

Hierachical epicuticular wax coverage on leaves of Deschampsia antarctica as a possible adaptation to severe environmental conditions

• Elena V. Gorb,
• Iryna A. Kozeretska and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2022, 13, 807–816, doi:10.3762/bjnano.13.71

• the wax on both epidermis and stomata contributes to the resistance of water vapor diffusion from the mesophyll to the outside and to the control of cuticle transpiration, reducing in this way the water loss by the leaf blade [9]. Also, authors associated the epicuticular wax on leaves along with

Efficient liquid exfoliation of KP₁₅ nanowires aided by Hansen's empirical theory

• Zhaoxuan Huang,
• Zhikang Jiang,
• Nan Tian,
• Disheng Yao,
• Fei Long,
• Yanhan Yang and
• Danmin Liu

Beilstein J. Nanotechnol. 2022, 13, 788–795, doi:10.3762/bjnano.13.69

• nanoparticles as anode materials to promote the rapid diffusion and electron transfer of lithium, and Rongjun Zhao prepared n-butanol gas sensors with one-dimensional In2O3 nanorods [1][2]. Different from 2D materials, 1D materials generally have a chain-like crystal structure and are easily exfoliated due to a

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

• clusters (PNCs), transition phases, and actual second building units (SBUs) in the prenucleation and growth steps (Figure 1). Transition and attachment of these species are not only controlled by thermodynamics but also strongly depend on kinetics. The decisive factors involve diffusion, local flow, and

• defined structures and flow characteristics. Thus, they are good experimental tools for the observation of crystallization process. The interfaces among the laminar fluids in microfluidic channels can be recognized as soft boundaries of crystallization zones. In the reaction–diffusion zone confined by

• –diffusion zone could be defined, leading to diffusion-limited and kinetically controlled environments. Nonequilibrium crystal morphologies were observed. Needles were found to assemble into frames, which were subsequently woven into plate-like single crystals. The channel walls of microfluidic reactors are

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

• is the electrode active area (cm2), Dr is the diffusion coefficient (7.6 × 10−6 cm2·s−1), and C0 is the concentration of K3Fe(CN)6 (mol·cm−3). From the slope of the plot of Ip vs ν1/2, the effective surface area for bare GCE and ERGO/GCE was calculated to be 0.0707 and 0.121 cm2, respectively, which

• microstructures of ERGO, which makes the graphene sheets more accessible to the electrolyte. It also facilitates electron transfer and diffusion of ions during the electrochemical process [28][34]. Electrochemical behavior of parathion at modified nanosensors Figure 5A depicts the CVs (first cycle) of bare GCE

• the scan rate suggests a surface-confined diffusion-controlled electrocatalytic process [21]. The slope of log Ipc as a function of log ν is 0.611 (>0.5), which confirms an adsorption-based reduction of PT on the modified electrode surface (Figure 7B). The reduction peak potential was shifted towards

Direct measurement of surface photovoltage by AC bias Kelvin probe force microscopy

• Masato Miyazaki,
• Yasuhiro Sugawara and
• Yan Jun Li

Beilstein J. Nanotechnol. 2022, 13, 712–720, doi:10.3762/bjnano.13.63

• features as band bending [3][4], the lifetimes of excited carriers [5][6][7], the minority carrier diffusion length [8][9], and the plasmonic effect [10][11][12]. The local SPV is usually measured by Kelvin probe force microscopy (KPFM) [13][14][15][16][17][18][19][20][21], which is based on atomic force

Design and selection of peptides to block the SARS-CoV-2 receptor binding domain by molecular docking

• Kendra Ramirez-Acosta,
• Ivan A. Rosales-Fuerte,
• J. Eduardo Perez-Sanchez,
• Alfredo Nuñez-Rivera,
• Josue Juarez and
• Ruben D. Cadena-Nava

Beilstein J. Nanotechnol. 2022, 13, 699–711, doi:10.3762/bjnano.13.62

• to be in the range of 43% to 65% of the size of the ACE2 peptide. Therefore, the diffusion of these peptides is faster. These results show the potential of the selected peptides to inhibit SARS-CoV-2, considering that their smaller size and faster diffusion will allow them to find the virus faster

• peptides) and faster design of peptides (41 peptides) based on the peptide binding site on the RBD, the number of hydrogen bonds, and the binding affinity. The peptide candidates have a nearly neutral charge at physiological pH and good solubility, which can benefit the diffusion of the molecules, allowing

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

• large surface area to offer abundant active sites for the electrochemical reactions and a large pore volume for effective accommodation of Li2O2 [7][8]. If accumulated Li2O2 is not completely decomposed during the charge, the reaction sites and diffusion pathways of electrolytes and oxygen species are

• sufficient diffusion pathways for oxygen and electrolyte in the cathode. The ratio of Zn/Co in the starting materials greatly affects the microstructure and porosity of the resulting bimetallic ZIF–carbon/CNT composites. The correlation between the microstructure and the electrochemical performance of the

• which the highly porous ZnxCoy–C particles are beneficial for facilitating the electrochemical reactions between Li+ and O2. Moreover, CNT networks allow for sufficient electronic conduction as well as diffusion pathways for O2 and electrolyte in the composites. The atomic ratios of Zn and in the Zn1Co4

Experimental and theoretical study of field-dependent spin splitting at ferromagnetic insulator–superconductor interfaces

• Peter Machon,
• Michael J. Wolf,
• Detlef Beckmann and
• Wolfgang Belzig

Beilstein J. Nanotechnol. 2022, 13, 682–688, doi:10.3762/bjnano.13.60

• = e2/h is the conductance quantum, and G = σNA/d is the conductance of the film (in the direction perpendicular to the interface of cross section A). D and σN are the diffusion constant and the normal-state conductivity of the film, respectively. Note, that due to the normalization condition for

Antibacterial activity of a berberine nanoformulation

• Hue Thi Nguyen,
• Tuyet Nhung Pham,
• Anh-Tuan Le,
• Nguyen Thanh Thuy,
• Tran Quang Huy and
• Thuy Thi Thu Nguyen

Beilstein J. Nanotechnol. 2022, 13, 641–652, doi:10.3762/bjnano.13.56

• BBR NPs in water. Antibacterial activity The antibacterial activity of pure BBR and BBR NPs prepared at different concentrations against MRSA and E. coli O157:H7 was compared in vitro using the modified disk diffusion method. Figure 4 and Table 1 show the inhibitory zones of pure BBR (at the

• NPs by colony counting was more reliable than by the modified disk diffusion method. This finding can be explained by the low diffusion of BBR NPs on the agar surface. BBR NPs interacted more with bacteria in the nutrient broth for the colony counting method. BBR NPs with a high surface-to-volume

• sectioning for TEM observations. We did not find any difference in ultrastructural changes of E.coli O157:H7 cells treated with and without BBR NPs, whereas significant differences were found in MRSA cells after treatment with BBR NPs. This is consistent with results obtained using the disk diffusion method

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

• on the skin showing no penetration using the commercial applicator, c) MN penetration and fluorescein diffusion into the skin, using the custom-made impact applicator at 3 m/s impact velocity, d) as c) for 4.5 m/s impact velocity. Stereomicroscopy images for the estimation of APE using the custom

Comparative molecular dynamics simulations of thermal conductivities of aqueous and hydrocarbon nanofluids

• Adil Loya,
• Antash Najib,
• Fahad Aziz,
• Asif Khan,
• Guogang Ren and
• Kun Luo

Beilstein J. Nanotechnol. 2022, 13, 620–628, doi:10.3762/bjnano.13.54

• results [44]. Moreover, in earlier research, authors investigated the rheological and diffusion properties of a CuO nanofluid in water-based systems [45]. The present study is a continuation of that research and is focused on predicting the thermal conductivities of CuO nanoparticles in aqueous and

• nanoparticles shows high diffusion in water-based systems (i.e., around 4.5 × 10−9 m2/s) [45], in comparison to alkanes/polar (i.e., nonaqueous, around 4.35 × 10−11 m2/s) systems [52], as investigated by the two previous studies. This is further confirmed by a study by Abid et al. [53] in which various

• parameters (including dimensionless velocity) for water/CuO and kerosene/CuO were calculated using MATLAB. They found that water/CuO nanofluids have a much higher velocity than kerosene/CuO systems. Therefore, both the previous study by the authors regarding diffusion coefficient and the Abid et al. study

Approaching microwave photon sensitivity with Al Josephson junctions

• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Leonid S. Revin,
• Dmitry A. Ladeynov,
• Anton A. Yablokov and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2022, 13, 582–589, doi:10.3762/bjnano.13.50

• power, whose presence can be observed only in the switching distributions and in the shorter lifetime of the superconducting state. The used experimental setup is the same as in [7], except for the measured sample. In [7], the critical current of the sample was very low, and the phase diffusion regime

• was noticeably pronounced. The sample considered here has a much higher critical current, and the phase diffusion does not appear. As a result, the theoretical estimates based on the BCS theory for critical currents and Kramers’ theory for escape times are well applicable. Furthermore, the analysis of

• [7], where the phase-diffusion regime is possible [32][33][34][35][36][37], the analyzed junction demonstrates a typical behavior [4][38], that is, a monotonic increase in the switching current distribution width with the rise of the temperature, see Figure 3. For the switching current measurements

Ciprofloxacin-loaded dissolving polymeric microneedles as a potential therapeutic for the treatment of S. aureus skin infections

• Sharif Abdelghany,
• Walhan Alshaer,
• Yazan Al Thaher,
• Maram Al Fawares,
• Amal G. Al-Bakri,
• Saja Zuriekat and
• Randa SH. Mansour

Beilstein J. Nanotechnol. 2022, 13, 517–527, doi:10.3762/bjnano.13.43

• ]. These properties can facilitate the diffusion into the dermis and underlying layers for local and transdermal effects. In a recent study, PVP-based dissolving microneedles were able to deliver sinomenine hydrochloride to a skin depth of 200 µm in rats [57], which is significantly less than the depth

Design and characterization of polymeric microneedles containing extracts of Brazilian green propolis

• Camila Felix Vecchi,
• Rafaela Said dos Santos,
• Jéssica Bassi da Silva and
• Marcos Luciano Bruschi

Beilstein J. Nanotechnol. 2022, 13, 503–516, doi:10.3762/bjnano.13.42

• viable epidermis, without reaching the nerve endings that are in the dermis [4][5]. The perforation of the stratum corneum enables the release of bioactive molecules in the epidermis, which then reach the dermis and blood capillaries by diffusion [6]. This entire process occurs in a non-invasive

• holes created and will be taken, by diffusion, to the innermost layers to have its systemic action [5][12]. Coated microneedles are solid MNs made of inert material and coated with a formulation containing the drug to be administered [5][13]. After skin perforation, this lining is retained in 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

• determined by HPLC from the supernatant phase after ultracentrifugation. The encapsulation efficiency of the ETHs was calculated according to the following equation. Furthermore, an in vitro release study for six ETHs was performed for 24 h at 37 °C using Franz diffusion cells with a 12.000 Dalton pore size

The role of sulfonate groups and hydrogen bonding in the proton conductivity of two coordination networks

• Ali Javed,
• Felix Steinke,
• Stephan Wöhlbrandt,
• Hana Bunzen,
• Norbert Stock and
• Michael Tiemann

Beilstein J. Nanotechnol. 2022, 13, 437–443, doi:10.3762/bjnano.13.36

• conduction occurs by mass transport (i.e., by cation diffusion of, e.g., H3O+), activation energies higher than 0.4 eV are expected [28]. This mechanism seems to dominate the additional conduction mode in the non-activated Mg-CP sample, where an activation energy of 0.64 eV is observed. This is consistent

• with our above assumption that this additional conduction occurs within interparticle water adsorbate layers; these liquid-like layers may facilitate molecular diffusion to some extent. To explain the differences in proton conductivity between the (activated) Mg-CP and Pb-MOF materials, the respective

A non-enzymatic electrochemical hydrogen peroxide sensor based on copper oxide nanostructures

• Irena Mihailova,
• Vjaceslavs Gerbreders,
• Marina Krasovska,
• Eriks Sledevskis,
• Valdis Mizers,
• Andrejs Bulanovs and
• Andrejs Ogurcovs

Beilstein J. Nanotechnol. 2022, 13, 424–436, doi:10.3762/bjnano.13.35

• high-speed paths for analyte molecule transfer due to the high porosity of the surface, as well as more efficient mass diffusion and electron transfer processes compared to the less developed film. The sensitivity of pure CuO wire is significantly inferior to samples containing CuO. Figure 3c,d

• EIS curve and the corresponding equivalent circuit are presented. The absence of characteristic semicircles formed by RCs by the circuit elements indicates a low charge transfer resistance and the predominance of Warburg diffusion over other processes in the electrochemical system. Figure 3f shows an

• electrons transferred in the redox reaction, D is the diffusion coefficient in solution (D = 6.8 × 10−5 cm2·s−1), C* is the concentration (mol·cm−3); v is the scan rate (100 mV·s−1), and A denotes the effective surface area of the electrode (cm2). The electrochemically active surface area was calculated to