Elasticity, an often-overseen parameter in the development of nanoscale drug delivery systems

• Agnes-Valencia Weiss and
• Marc Schneider

Beilstein J. Nanotechnol. 2023, 14, 1149–1156, doi:10.3762/bjnano.14.95

• , translation to the clinics or even market approval often fails. So far, the reason for this discrepancy is manifold. Physicochemical properties such as size, surface potential, and surface chemistry are in focus of research for many years. Other equally important parameters, influencing whether a successful

• develop methods and devices and formulation scientists could improve standard characterization techniques, such as size or surface potential, which are already given in almost every study involving nanoparticles. A full characterization with respect to size, surface potential, corona formation on the

Dual-heterodyne Kelvin probe force microscopy

• Benjamin Grévin,
• Fatima Husainy,
• Dmitry Aldakov and
• Cyril Aumaître

Beilstein J. Nanotechnol. 2023, 14, 1068–1084, doi:10.3762/bjnano.14.88

• achieved by using two numerical lock-in amplifiers configured in cascade. Dual-heterodyne KPFM (DHe-KPFM) can be used to map any harmonic (amplitude/phase) of the time-periodic surface potential at a standard scanning speed. The Fourier spectrum (series of harmonics) can also be recorded in spectroscopic

• measurements [16], which consists in analysing the intermodulation products between the mechanical oscillation of the cantilever and the photogenerated surface potential. In short, intermodulation spectroscopy allows working in the frequency domain (instead of the time domain) by extracting, during a single

• AFM under ultra-high vacuum in a slightly different way. We demonstrate that the Fourier spectrum (modulus and phase coefficients) of the time-periodic electrostatic surface potential generated under optical (or electrical) pumping can be probed, by exploiting a double heterodyne frequency mixing

Antibody-conjugated nanoparticles for target-specific drug delivery of chemotherapeutics

• Mamta Kumari,
• Amitabha Acharya and
• Praveen Thaggikuppe Krishnamurthy

Beilstein J. Nanotechnol. 2023, 14, 912–926, doi:10.3762/bjnano.14.75

• affected by their physicochemical properties, including hydrodynamic diameter, surface potential, shape, functional groups, and hydrophobicity. The protein corona reduces the targeted delivery of NPs by disturbing or inhibiting the binding of target molecules to their receptors. Mirshafiee et al. used a

• effect makes the NPs very selective and provides a high sensitivity for binding on the target surface. Multicomponent effect of protein corona on antibody-conjugated NPs The small hydrodynamic diameter and unique structure of NPs offer increased adsorption and catalytic efficiency. The NP surface

• potential plays an essential role in the interaction between protein and NPs as opposite charges produce strong interaction and result in high conformational changes [76]. The conjugation of antibodies on nanoparticle surfaces enhances the delivery of drug cargo specifically to disease sites. Once NPs enter

Cross-sectional Kelvin probe force microscopy on III–V epitaxial multilayer stacks: challenges and perspectives

• Mattia da Lisca,
• José Alvarez,
• James P. Connolly,
• Nicolas Vaissiere,
• Karim Mekhazni,
• Jean Decobert and
• Jean-Paul Kleider

Beilstein J. Nanotechnol. 2023, 14, 725–737, doi:10.3762/bjnano.14.59

• technique for the analysis of an InP/GaInAs(P) multilayer stack. KPFM reveals a strong dependence on the local doping concentration, allowing for the detection of the surface potential of layers with a resolution as low as 20 nm. The analysis of the surface potential allowed for the identification of space

• charge regions and, thus, the presence of several junctions along the stack. Furthermore, a contrast enhancement in the surface potential image was observed when KPFM was performed under illumination, which is analysed in terms of the reduction of surface band bending induced by surface defects by

• of the atomic force microscope (AFM) for the evaluation of the surface potential with nanometric resolution. KPFM is a valuable investigative approach for the study of work functions via the measurement of the contact potential difference VCPD, that is, the difference between the electrostatic

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

• that of the intrinsic semiconductor [19]. Thus, since the CPD is strongly affected by the surface properties, accurate evaluation of the surface state and bulk impurity concentration requires a method that extracts only the surface potential effect due to interface states. Recently, we proposed high

• by the CPD, is applied to the semiconductor sample. Therefore, the surface potential of the semiconductor is fixed at a certain energy, and only the surface state near the Fermi level of the surface is reflected in CPD measurements, making measurement of the energy distribution of the interface

• , respectively. The modulated electrostatic force Fele(f) between the tip and the surface is expressed as follows using Taylor series expansion: where Vs is the surface potential of the semiconductor sample. Next, we consider the charge Q induced on the semiconductor surface. When a bias voltage is applied

Utilizing the surface potential of a solid electrolyte region as the potential reference in Kelvin probe force microscopy

• Nobuyuki Ishida

Beilstein J. Nanotechnol. 2022, 13, 1558–1563, doi:10.3762/bjnano.13.129

• electrodes. In Kelvin probe force microscopy (KPFM) measurements on electrochemical cells, the surface potential is generally measured relative to electrical ground instead of a stable reference. Here, we show that the changes in the surface potential, measured using KPFM relative to the surface potential in

• the electrolyte region, is consistent with the changes in the electrode potential measured using a voltmeter relative to a reference electrode. These results demonstrate that the surface potential in the electrolyte region can be utilized as a stable potential reference when analyzing KPFM data

• electrode placed on a solid electrolyte (Li-ion conductor) substrate. The surface-potential distribution in the region across the solid electrolyte was measured with a DC voltage applied between the Au electrodes. During the KPFM measurements, the potential of each Au electrodes relative to the Li electrode

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

• resistance and surface potential, directly contribute to the flow potential. At the same time, the parameters of the fluid in the nanochannel, such as dielectric constant and ion concentration, are directly related to the magnitude of the flow potential. In the nanochannel, the flow velocity ν of the fluid

Comparing the performance of single and multifrequency Kelvin probe force microscopy techniques in air and water

• Jason I. Kilpatrick,
• Emrullah Kargin and
• Brian J. Rodriguez

Beilstein J. Nanotechnol. 2022, 13, 922–943, doi:10.3762/bjnano.13.82

• resolution [13][15][16][17][18][19]. These advances have enabled investigations mapping light-induced surface potential dynamics [20], ferroelectric domains [19], individual quantum dots [21][22], and even submolecular charge distributions [23][24][25][26][27]. These applications demonstrate that KPFM is

• from measurements in order to access a true surface potential map [78][79]. A natural extension of AM-KPFM is dual-harmonic KPFM (DH-KPFM), which is an OL technique that utilizes the measurement of both the first and second harmonic of the electrostatic response (ωe and 2ωe). By combining these two

• the surface potential [53][76][86] and has enhanced our understanding of perovskite solar cells [10][87][88] and patch potentials in the Casimir force [89][90]. Implementations of Het-KPFM to date have primarily focused on the measurement of the first harmonic of the electrostatic force [57][58

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

• KPFM. Moreover, AC-KPFM is applicable in both amplitude modulation and frequency modulation mode. Thus, it contributes to advancing SPV measurements in various environments, such as vacuum, air, and liquids. This method can be utilized for direct measurements of changes in surface potential induced by

• modulated external disturbances. Keywords: atomic force microscopy; Kelvin probe force microscopy; photocatalyst; surface photovoltage; titanium dioxide; Introduction Surface photovoltage (SPV) is the change in surface potential caused by light illumination [1][2] and is measured to determine such

• changes in surface potential induced by modulated external disturbances such as electric fields, magnetic fields [70][71], and stress fields [72][73]. Appendix Sensitivity of AC-KPFM in the FM mode The sensitivity of AC-KPFM in the FM mode is comparable to the sensitivity of FM-KPFM. The frequency noise

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

• PEP-FOLD3.5’s model prediction servers using the reported peptide sequence for those that lacked it [28][29][30][31][32]. All peptides analyzed were compared with the ACE2-derived peptide IEEQAKTFLDKFNHEAEDLFYQSS (I21 to S44 of ACE2) [7]. The electrostatic surface potential, hydrophobic interactions

• surface of the RBD. Figure 1b shows the electrostatic surface potential of the RBD active region, in which negatively charged, neutral, and positively charged patches can be identified, depending on the amino acid residues. Therefore, it can be assumed that electrostatic repulsion forces are negligible

• with ACE2 (Table 3 and Figure 5), as will be shown next. Figure 5b shows that the binding energy values vary independently of the net charge of the OAPs. This can be explained based on the electrostatic surface potential of the active region of the RBD (inset in Figure 5b), which can be divided into

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

• included for four cases in (b,c). (d) Projection of the interaction force on the -axis. (e) Δf() curves calculated for four different inclination angles and starting points. (a) Heterogeneous surface potential with the tip–sample force vector field indicated by arrows (same as Figure 3a). (b) Vertical

Detection and imaging of Hg(II) in vivo using glutathione-functionalized gold nanoparticles

• Gufeng Li,
• Shaoqing Li,
• Rui Wang,
• Min Yang,
• Lizhu Zhang,
• Yanli Zhang,
• Wenrong Yang and
• Hongbin Wang

Beilstein J. Nanotechnol. 2022, 13, 549–559, doi:10.3762/bjnano.13.46

• charges of GNPs, GNPs-GSH, and GNPs-GSH-Rh6G2 are shown in Figure 2d. Once GNPs were modified with GSH, the surface potential increased from −34.5 to −12.1 mV due to the positive surface charges of GSH. After further modifying with Rh6G2, the zeta potential increased to −8 mV. These results indicated that

Topographic signatures and manipulations of Fe atoms, CO molecules and NaCl islands on superconducting Pb(111)

• Carl Drechsel,
• Philipp D’Astolfo,
• Jung-Ching Liu,
• Thilo Glatzel,
• Rémy Pawlak and
• Ernst Meyer

Beilstein J. Nanotechnol. 2022, 13, 1–9, doi:10.3762/bjnano.13.1

• features resemble typical patterns observed in friction force microscopy (FFM) [28][38] or scanning tunneling hydrogen microscopy (SThM) [70][71], since the trapped Fe atom senses the surface potential in analogy to the probing tip of FFM. For clarity, we overlay the Pb(111) surface lattice on top of the

Measurement of polarization effects in dual-phase ceria-based oxygen permeation membranes using Kelvin probe force microscopy

• Kerstin Neuhaus,
• Christina Schmidt,
• Liudmila Fischer,
• Wilhelm Albert Meulenberg,
• Ke Ran,
• Joachim Mayer and
• Stefan Baumann

Beilstein J. Nanotechnol. 2021, 12, 1380–1391, doi:10.3762/bjnano.12.102

• |ceria, ceria|electron conductor, and electron conductor|electron conductor). Kelvin probe force microscopy (KPFM) is an atomic force microscopy (AFM)-based measurement method that can measure the local surface potential (or Volta potential) of the sample [18][19]. The surface potential is a sensitive

• % FeCo2O4 (CSO-FC2O) as electron-conductive phase in order to, first, locally change the defect chemistry of the material and, then, study the relaxation to the original surface potential state during uptake/release of oxygen from/to the surrounding air. By using an AFM tip as an electron-conductive

• nanoscale electrode, a constant voltage pulse was applied to the sample in order to achieve a local polarization with distinctly changed redox state and defect concentrations. In a subsequent mapping experiment, the AFM tip was used as Kelvin probe to scan the locally changed surface potential distribution

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

• hand, it should be noted that the increase in surface charge density can also directly increase the bare surface potential, thus increasing the zeta potential, denoted by ζ, which is a key parameter that reflects the amplitude of the electrokinetic effects. Therefore, the increase in surface charge

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

• potential resembled that of NOR@IONPpH5 but the drug loading achieved was 3 times lower than that achieved in the NOR@IONPpH5 system of this study (Table 2). Thus, NOR@IONPpH5 resembled the NOR@IONPs from our previous study in the surface potential but differed in size. Drug release and coating estimation

Open-loop amplitude-modulation Kelvin probe force microscopy operated in single-pass PeakForce tapping mode

• Gheorghe Stan and
• Pradeep Namboodiri

Beilstein J. Nanotechnol. 2021, 12, 1115–1126, doi:10.3762/bjnano.12.83

• probe force microscopy; open loop; surface potential; Introduction Over many years, an abundance of developments and applications has made Kelvin probe force microscopy (KPFM) [1] one of the most versatile nanoscale surface electronic characterization techniques. With its main measurement in terms of

• the local contact potential difference (CPD) between a conductive AFM probe and a surface, KPFM has been used for qualitative and quantitative electric characterizations. Examples include surface potential, doping, charge profiling, optoelectronic response, and others on various materials and

• calibrating the local CPD on sample regions of known surface potential. This simple and practical deconvolution increased the spatial resolution of the OL AM-KPFM at the level of an FM-KPFM method. The OL KPFM variant proposed here adds to a growing set of PFT-based platform techniques that includes

The role of deep eutectic solvents and carrageenan in synthesizing biocompatible anisotropic metal nanoparticles

• Nabojit Das,
• Akash Kumar and
• Raja Gopal Rayavarapu

Beilstein J. Nanotechnol. 2021, 12, 924–938, doi:10.3762/bjnano.12.69

• asymmetric distribution of charged lipids between the two leaflets of the plasma membrane. This lead to a negative charged of the inner leaflet generating a surface potential and the binding affinity towards positively charged moieties. However, an interesting study revealed a structure-dependent

Local stiffness and work function variations of hexagonal boron nitride on Cu(111)

• Abhishek Grewal,
• Yuqi Wang,
• Matthias Münks,
• Klaus Kern and
• Markus Ternes

Beilstein J. Nanotechnol. 2021, 12, 559–565, doi:10.3762/bjnano.12.46

• work function is generally discussed in the framework of a macroscopic quantity [36], we will use the notation, valid also on the nanoscale, that Φ is the local surface potential measured from the Fermi level, EF [37]. For a nanoscale patterned surface, such as h-BN/Cu(111), Φ fluctuations can

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

• rectangles represent the triboelectric materials with different dielectric constants. The length and width are set as 50 mm and 0.1 mm, respectively. By changing the distance (ds), we simulate the process of the triboelectric materials approaching and moving away from each other. Figure 3a is the surface

• potential distribution diagram of the triboelectric materials of a TENG at a distance of 1 mm. Due to the influence of the relative permittivity, the material with the lower relative permittivity is negatively charged, while the other triboelectric material is positively charged. When the distance between

Rapid controlled synthesis of gold–platinum nanorods with excellent photothermal properties under 808 nm excitation

• Jialin Wang,
• Qianqian Duan,
• Min Yang,
• Boye Zhang,
• Li Guo,
• Pengcui Li,
• Wendong Zhang and
• Shengbo Sang

Beilstein J. Nanotechnol. 2021, 12, 462–472, doi:10.3762/bjnano.12.37

• at the surface of the AuNRs with a lower surface potential than the reduction potential of Ag+ [27]. Electrochemical and crystallographic studies have shown that deposition of Ag+ on the side of the AuNRs (i.e., {110} facets) should be faster than on the tip (i.e., {100} facets) [33]. Another reason

The nanomorphology of cell surfaces of adhered osteoblasts

• Christian Voelkner,
• Mirco Wendt,
• Regina Lange,
• Max Ulbrich,
• Martina Gruening,
• Susanne Staehlke,
• Barbara Nebe,
• Ingo Barke and
• Sylvia Speller

Beilstein J. Nanotechnol. 2021, 12, 242–256, doi:10.3762/bjnano.12.20

• using the SurPASS™ system (Anton Paar, Ostfildern, Germany) to determine the surface potential. Au- and PPAAm-modified titanium substrates were placed in pairs in the measuring chamber with a gap height of 100 μm. The streaming potential was measured at pH 6.5 to 8.0, at 150 mbar in a 1 mM KCl solution

Mapping the local dielectric constant of a biological nanostructured system

• Wescley Walison Valeriano,
• Rodrigo Ribeiro Andrade,
• Juan Pablo Vasco,
• Angelo Malachias,
• Bernardo Ruegger Almeida Neves,
• Paulo Sergio Soares Guimarães and
• Wagner Nunes Rodrigues

Beilstein J. Nanotechnol. 2021, 12, 139–150, doi:10.3762/bjnano.12.11

• voltage, we obtain a parabolic function, as can be seen in Figure 4. Fitting the data with the function where VSP is the tip–sample surface potential difference due to their different work functions [21], we obtain the coefficient α. Construction of the relative permittivity map From the topographic image

Bulk chemical composition contrast from attractive forces in AFM force spectroscopy

• Dorothee Silbernagl,
• Media Ghasem Zadeh Khorasani,
• Natalia Cano Murillo,
• Anna Maria Elert and
• Heinz Sturm

Beilstein J. Nanotechnol. 2021, 12, 58–71, doi:10.3762/bjnano.12.5

• field is applied. Khorasani and coworkers identified nanoparticles (exposed and subsurface) in an epoxy/boehmite nanocomposite by measuring the surface potential by means of KPM [9]. A disadvantage of KPM is that, in addition to the apex of the tip, the sides of the tip are also interacting. This leads

Influence of the magnetic nanoparticle coating on the magnetic relaxation time

• Mihaela Osaci and
• Matteo Cacciola

Beilstein J. Nanotechnol. 2020, 11, 1207–1216, doi:10.3762/bjnano.11.105

• surface potential of the i-th nanoparticle at infinite separation, z is the ion valence, e = 1.6 × 10−19 C and k is the thickness of the screening ionic layer “κ”, estimated by the inverse of Debye constant. Polymers and surfactants are usually used for steric stabilization. The model uses the following