High–low Kelvin probe force spectroscopy for measuring the interface state density

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

Beilstein J. Nanotechnol. 2023, 14, 175–189, doi:10.3762/bjnano.14.18

• between a metal tip and a semiconductor surface, a surface potential is generated on the semiconductor surface, resulting in, for example, surface charge accumulation, depletion, and inversion states. The relationship between this surface charge and the electrostatic force between the tip and the sample

• have been performed on a variety of sample surfaces, including metals [9][10], semiconductors [11][12][13][14], and insulators [15][16][17]. When a semiconductor sample is measured by KPFM, the measured CPD is related to information about the semiconductor properties such as dopant density, surface

• charge, band bending, and interface state density [18]. In particular, previous studies of silicon substrates with different impurity concentrations measured by KPFM have shown that when the impurity concentration is very high (>1016 cm−3), surface band bending occurs, and the measured CPD approaches

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

• commercially available antibiotics. The main parameters that determine the antibacterial action of CQDs are generation of reactive oxygen species, cytoplasm leakage due to DNA binding, and gene expression modulation [28]. In addition, the CQD surface charge affects very much the antibacterial activity of CQDs

Non-stoichiometric magnetite as catalyst for the photocatalytic degradation of phenol and 2,6-dibromo-4-methylphenol – a new approach in water treatment

• Joanna Kisała,
• Anna Tomaszewska and
• Przemysław Kolek

Beilstein J. Nanotechnol. 2022, 13, 1531–1540, doi:10.3762/bjnano.13.126

• is strongly affected by the surface charge. The point of zero charge (PZC) is defined as the pH value at which the catalyst exhibits a net zero surface charge. At pH values below the PZC, the surface of the catalyst is protonated and has a positive net surface charge. In turn, the net surface charge

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

• -PLGA NPs had positive surface charge with CS coating. The formulations have the potential to deliver the encapsulated drug to the bowel according to the in vitro release studies in three different simulated GIT fluids for approximately 72 h. Mucin interaction and penetration into the artificial mucus

• colonic microflora. It has been reported that nanoparticles prepared with polymers such as chitosan, whose surface charge is positive, remain longer in the mucus due to electrostatic interaction with the negative charge of the aqueous mucin layer [15][29][30][31]. Docetaxel (DCX) is obtained semi

• into the nanoparticles as a model anticancer agent. CS coating was used to impart positive surface charge to negatively charged PLGA nanoparticles and to increase their interaction in the intestinal lumen. To date, an orally applicable and effective treatment approach to colon tumors has not been

LED-light-activated photocatalytic performance of metal-free carbon-modified hexagonal boron nitride towards degradation of methylene blue and phenol

• Nirmalendu S. Mishra and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2022, 13, 1380–1392, doi:10.3762/bjnano.13.114

• a Shimadzu TOC-L CSH analyser. The surface area and pore characteristics were characterized by a Micromeritics (3FLEX 3500) gas sorption analyser. The surface charge was analysed through a Zeta-Meter 4.0 (Zeta-Meter, Inc, USA). The electron paramagnetic resonance (EPR) experiments were performed by

• charge is an important parameter which governs the adsorption of the pollutant moiety over the photocatalyst. Thus, it becomes very important to study the variation of surface charge of the MBN-80. The variation of surface charge over MBN-80 in terms of pH value and isoelectric point of the solution was

• attributed to the unpaired electrons. The MBN-80 sample shows the highest EPR spin intensity, meaning greater concentration of unpaired electrons along with higher electron delocalization which are highly favourable towards enhanced separation and generation of charge carriers [26][27]. Additionally, surface

Application of nanoarchitectonics in moist-electric generation

• Jia-Cheng Feng and
• Hong Xia

Beilstein J. Nanotechnol. 2022, 13, 1185–1200, doi:10.3762/bjnano.13.99

• occurs when a liquid is in contact with a solid with a surface charge. This interaction is mainly dominated by the electric double layer (EDL), which consists of a layer of ions (Stern layer) that is tightly adsorbed to the charged surface and a layer of counter ions (diffusion layer) that is attracted

• 4.0. (b, c) Cross-sectional SEM images of a Ni–Al LDH film. Figure 4b and 4c were adapted from [52]. This article was published in Nano Energy, vol. 70, by J. Tian; Y. Zang; J. Sun; J. Qu; F. Gao; G. Liang, “Surface charge density-dependent performance of Ni–Al layered double hydroxide-based flexible

Green synthesis of zinc oxide nanoparticles toward highly efficient photocatalysis and antibacterial application

• Vo Thi Thu Nhu,
• Nguyen Duy Dat,
• Le-Minh Tam and
• Nguyen Hoang Phuong

Beilstein J. Nanotechnol. 2022, 13, 1108–1119, doi:10.3762/bjnano.13.94

• (Figure 6b). The bandgap energy of synthesized ZnO was 3.15 eV, which is close to the bandgap value of 3.2 eV of ZnO shown in a previous report [33]. The zeta potential value displays the surface charge and stability of ZnO NPs. In this study, the zeta potential of ZnO NPs was −19 mV (Figure 7

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

• not allow good and sufficient cell attachment necessary for tissue engineering applications. However, several independent studies showed that the materials made of the positively charged eADF4(κ16) variant enabled partial cell adhesion due to the positive surface charge derived from lysine residues in

• the primary amino acid sequence [150][162][163]. Since cells expose many negatively charged molecules on their cellular surface, charge modification is often used to guide cellular interaction [164][165][166]. In the example of the recombinant 4RepCT spider silk, several charged amino acid residues in

Gelatin nanoparticles with tunable mechanical properties: effect of crosslinking time and loading

• Agnes-Valencia Weiss,
• Daniel Schorr,
• Julia K. Metz,
• Metin Yildirim,
• Saeed Ahmad Khan and
• Marc Schneider

Beilstein J. Nanotechnol. 2022, 13, 778–787, doi:10.3762/bjnano.13.68

• optimal treatment. Therefore, the characteristics of nanoparticles regarding mechanical properties, size, surface charge, surface composition, and degradation and drug release mechanisms must be considered during formulation development [1]. Except for the mechanical properties, the research activities do

• macromolecules, such as proteins [12] and peptides [13], or in the field of gene delivery [14]. The surface charge of gelatin nanoparticles at physiological pH can be easily influenced by the choice of gelatin type [15]. Crosslinking of gelatin nanoparticles is still inevitable to obtain particles that are

• polydispersity index (PdI) from 0.075 to 0.115, indicating a narrow size distribution. Crosslinking for 15 min did not result in stable particles with uniform colloidal properties. The surface charge of gelatin nanoparticles is clearly pH-dependent. At a pH value of 7.5 ± 0.1, the zeta potential values ranged

Stimuli-responsive polypeptide nanogels for trypsin inhibition

• Petr Šálek,
• Jana Dvořáková,
• Sviatoslav Hladysh,
• Diana Oleshchuk,
• Ewa Pavlova,
• Jan Kučka and
• Vladimír Proks

Beilstein J. Nanotechnol. 2022, 13, 538–548, doi:10.3762/bjnano.13.45

• varied from 0.233 to 0.258 at 25 °C and from 0.233 to 0.289 at 37 °C within the tested pH range from 4 to 7.4. Therefore, we assumed that the dependence of DH of Nα-Lys-NG nanogel on the pH could be significantly distorted. The surface charge analysis showed that Nα-Lys-NG nanogel was more anionic in

The effect of metal surface nanomorphology on the output performance of a TENG

• Yiru Wang,
• Xin Zhao,
• Yang Liu and
• Wenjun Zhou

Beilstein J. Nanotechnol. 2022, 13, 298–312, doi:10.3762/bjnano.13.25

• charge density [35][36][37], (2) reduction of the impact of the external environment on TENGs [38][39], (3) enhancement of the surface charge density, including active charge pumping and intercalation of a charge trap layer [40][41], and (4) increase of the number of TENG units [42][43]. In order to

• improve the surface charge density in the contact electrification process, it is necessary to expand the effective contact surface area by surface engineering of micro-/nanoscale structures [44][45][46]. There are various processes for the surface engineering of polymers with micro-/nanoscale structures

• sizes on the energy harvesting efficiency of the TENG were studied. The enhancement effect of different surface charge density distributions on the output performance of the nanostructured metal TENGs is explained. Experimental Materials and characterization In this study, 1 M sulfuric acid, copper

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

• anodic polarization results in a net positive surface charge [36][37], caused by the accumulation of the dissolved metal cations on the inner layer and strengthens the adhesion of the negatively charged silicon AFM tip [38][39]. Figure 5d depicts schematically this charge buildup at the surface of the

• reveals a stable surface charge with different periods of immersion time. We conclude that there is an equilibrium between the production of metal cations by dissolution and diffusion of the ions into the solution, which entails the constant surface charge. In other words, during immersion in phosphate

• buffer, the ion transfer is limited by the dissolution rate. Anodic polarization in phosphate buffer with its stronger metal ion dissolution leads to an accumulation of cations on the surface and, thus, to a higher surface charge. In NaCl solution, adhesion increases with immersion time, indicating an

Engineered titania nanomaterials in advanced clinical applications

• Padmavati Sahare,
• Paulina Govea Alvarez,
• Juan Manual Sanchez Yanez,
• Gabriel Luna-Bárcenas,
• Samik Chakraborty,
• Sujay Paul and
• Miriam Estevez

Beilstein J. Nanotechnol. 2022, 13, 201–218, doi:10.3762/bjnano.13.15

• found that nps smaller than 100 nm produce more ROS due to their higher surface area [29]. Properties of nps such as surface charge density and zeta potential are influential in determining their reactivity, agglomeration properties, interaction with cells, stability in complex media, and adsorption of

• prevention of agglomeration [102]. Titania nanostructures are capable of loading molecules of various sizes, charges, and solubilities. The immobilization of drugs and their release profile is affected by the size and surface charge distribution of the drug molecule. It has been stated that for the long-term

Theranostic potential of self-luminescent branched polyethyleneimine-coated superparamagnetic iron oxide nanoparticles

• Rouhollah Khodadust,
• Ozlem Unal and
• Havva Yagci Acar

Beilstein J. Nanotechnol. 2022, 13, 82–95, doi:10.3762/bjnano.13.6

• and a positive surface charge. The former is very important for the pharmacokinetics of nanoparticles and needed for long blood circulation time, especially when a molecular targeting is aimed [36][37][38]. The latter is essential for the highly popular gene therapy, especially in the treatment of

Biocompatibility and cytotoxicity in vitro of surface-functionalized drug-loaded spinel ferrite nanoparticles

• Sadaf Mushtaq,
• Khuram Shahzad,
• Tariq Saeed,
• Anwar Ul-Hamid,
• Bilal Haider Abbasi,
• Nafees Ahmad,
• Waqas Khalid,
• Muhammad Atif,
• Zulqurnain Ali and
• Rashda Abbasi

Beilstein J. Nanotechnol. 2021, 12, 1339–1364, doi:10.3762/bjnano.12.99

• electrophoresis. All samples moved towards the positive potential due to the negatively charged PMA coating (Figure 2d). The colloidal stability (i.e., hydrodynamic size, surface charge, and polydispersity index, PDI) of NPs was assessed using dynamic light scattering (DLS). All NPs (PMA-coated, and drug-attached

• ) dispersed in deionized water, sodium borate buffer (SBB) pH 9.0, phosphate buffer saline (PBS) pH 7.4, and DMEM were used for zeta potential measurements. The purpose of using buffers (i.e., SBB, PBS) was to get indirect surface charge information. Deionized water was used to check the influence of

• drug molecules and NPs were acid labile in nature, resulting in the detachment of the drug from NPs under acidic conditions (pH. 5.5) [32]. The drug release became slower and sustained after that. Acidic conditions change the surface charge density which causes deionization of amide bonds, resulting in

Identifying diverse metal oxide nanomaterials with lethal effects on embryonic zebrafish using machine learning

• Richard Liam Marchese Robinson,
• Haralambos Sarimveis,
• Philip Doganis,
• Xiaodong Jia,
• Marianna Kotzabasaki,
• Christiana Gousiadou,
• Stacey Lynn Harper and
• Terry Wilkins

Beilstein J. Nanotechnol. 2021, 12, 1297–1325, doi:10.3762/bjnano.12.97

• representing different qualitative characteristic values for core shape, surface charge and purity [31], or the presence/absence of surface functional groups as important. Also, for example, elevated significance could be assigned to variables such as the Pauling metal atom electronegativity and the average

• variability in biological effects [28][29][31]. It is possible that our results regarding the limited significance of surface characteristics may be skewed by the manner in which surface chemical composition was represented using descriptors and the incomplete availability of surface charge information. (See

• for modelling of the 120 hpf excess lethality data could reflect biological significance arising from the nature of any surface coatings, rather than the presence or absence of any organic coating having general significance. Second, qualitative surface charge information, including “unknown” status

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

• this conclusion was drawn based on an ideal Lennard–Jones fluid. Its applicability on other Newtonian fluids with properties such as polarity and even on non-Newtonian fluids should be further validated. 2.2 Surface charge effects Investigating electrokinetics phenomena, including electro-osmosis

• applied electric field. Due to the surface charge on the solid surface, an electrical double layer (EDL), which is comprised of oppositely charged ions, naturally forms within the liquid in the vicinity of the solid surface. As shown in Figure 5, the EDL consists of an immobile Stern layer and a mobile

• experience a slippage [80]. In addition, the hydrodynamic slippage at the solid–liquid interface can in turn largely enhance the electro-osmotic velocity, which increases the urgency for a deep research on the liquid slippage phenomena in electrokinetics. Owing to the direct influence of surface charge

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

• material upon interaction with target gas analytes arise due to changes in, for instance, energy bands, surface charge, and work function caused by temperature, grain size, crystal plane energies, and doping [87][90][91]. Thus, there is no single sensing mechanism that explains all SMO gas sensors. The

pH-driven enhancement of anti-tubercular drug loading on iron oxide nanoparticles for drug delivery in macrophages

• Karishma Berta Cotta,
• Sarika Mehra and
• Rajdip Bandyopadhyaya

Beilstein J. Nanotechnol. 2021, 12, 1127–1139, doi:10.3762/bjnano.12.84

•  1). The NOR@IONPs also carry a surface charge and neutral pH. Thus indicating that these particles indeed have an improved stability, possibly due to the coating of drug. NOR@IONPpH5 also appear to have a higher drug loading. It was noted that both NOR@IONPpH5 and NOR@IONPpH10 had 2–3 nm larger

• identical treatment conditions (Figure 6a). The increased uptake could be due to active engulfment of nanoparticles by macrophages, due to their larger size (20–120 nm size range) and surface charge (+29 mV or −16.5 mV) [46], which results in simultaneous internalization of larger amounts of drug. Figure 6b

Modification of a SERS-active Ag surface to promote adsorption of charged analytes: effect of Cu²⁺ ions

• Bahdan V. Ranishenka,
• Andrei Yu. Panarin,
• Irina A. Chelnokova,
• Sergei N. Terekhov,
• Peter Mojzes and
• Vadim V. Shmanai

Beilstein J. Nanotechnol. 2021, 12, 902–912, doi:10.3762/bjnano.12.67

• charged hydrophilic thiols (sodium 2-mercaptoethyl sulfonate, mercaptopropionic acid, 2-mercaptoethanol, 2-(dimethylamino)ethanethiol hydrochloride, and thiocholine) to vary the surface charge of the SERS substrate. We used two oppositely charged porphyrins, cationic copper(II) tetrakis(4-N-methylpyridyl

• the surface charge of the substrate, which tends to be negative. Using the data obtained and our model SERS system, we analyzed the modification of the Ag surface by different reagents (lithium chloride, polyethylenimine, polyhexamethylene guanidine, and multicharged metal ions). Finally, all those

• suggest that some negatively charged centers are still present at the NP surfaces after thiocholine modification, such as, for example, adsorbed chloride thiocholine counter ions, which contribute to the resulting surface charge. The experimental data obtained support previous reports about the great

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

Recent progress in actuation technologies of micro/nanorobots

• Ke Xu and
• Bing Liu

Beilstein J. Nanotechnol. 2021, 12, 756–765, doi:10.3762/bjnano.12.59

• conductive materials into a micro/nanorobot and then adjusting the surface charge of the robot or the electrochemical reaction on the interface through electric fields can also yield actuation. Zhang et al. [29] proposed an interdigital microelectrode system. When an AC electric field is applied, metal

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

• medical products may be related to human exposure and safety as AgNPs may undergo complex transformations in biological media [6]. It is well known that AgNP physicochemical characteristics, such as size, shape, surface charge, surface functionalization, or core composition determine their interactions

• such conditions, the repulsive electrostatic forces between particles with the same surface charge are weakened, leading to aggregation upon collision [10]. The AgNPs with bulky coatings are less sensitive to this, since their stabilisation is steric and not electrostatic [14]. The dissolution of AgNPs

• AgNPs in artificial biological media In order to gain more coherent insight into the transformation of different AgNPs in biological media, we examined changes in their size, surface charge, and dissolution in simpler media (i.e., CCM, m(CCM+BSA), mCYS, m(CYS+BSA), mGSH, m(GSH+BSA), ALF, and AGF, see

The preparation temperature influences the physicochemical nature and activity of nanoceria

• Robert A. Yokel,
• Wendel Wohlleben,
• Johannes Georg Keller,
• Matthew L. Hancock,
• Jason M. Unrine,
• D. Allan Butterfield and
• Eric A. Grulke

Beilstein J. Nanotechnol. 2021, 12, 525–540, doi:10.3762/bjnano.12.43

• , compared to 6.5 to 13.2 nm for the as-prepared nanoceria. After 75 days of dissolution, the surface charge was −9 mV, compared to the as-prepared nanoceria surface charge of −40 mV, suggesting the loss of the citrate coating. RAW 264.7 cell exposure to the as-prepared solvothermally synthesized nanoceria

• the exposure to partially dissolved nanoceria may be due to the increased surface content of Ce3+ providing antioxidant potential. After dialysis in water, the partially dissolved nanoceria rapidly precipitates from the dispersion, presumably due to the loss of surface citrate and reduced surface

• charge. The particles do not pass through a 0.2 micrometer MWCO filter, suggesting that they were quite large, which may have affected cell uptake. The results illustrate an effect of nanoceria dissolution on its biological identity. Nanoceria reactivity Nanoceria reactivity increased as the content of

Simulation of gas sensing with a triboelectric nanogenerator

• Kaiqin Zhao,
• Hua Gan,
• Huan Li,
• Ziyu Liu and
• Zhiyuan Zhu

Beilstein J. Nanotechnol. 2021, 12, 507–516, doi:10.3762/bjnano.12.41

• area. Further, in order to eliminate the inevitable topological change during the actual movement of the TENG, an air gap was established in COMSOL to construct the two-dimensional model of the TENG. Based on the assumption that the surface charge density of the triboelectric nanogenerator is constant

• materials approach or move away from each other, other substances, such as water vapor, carbon dioxide, and other gases, can pass through the gap. We present a simulation with water vapor under ideal conditions, that is, the surface charge density may be changed during the experiment. A simplified two

• triboelectric materials is helpful for distinguishing different gases. It is noted that water or humidity can degrade the surface charge density of the electrification surfaces in an actual experiment. We will carry out further investigations in the future. Conclusion Simulations of three differently shaped