An analysis is conducted of application of the Hertz model for measuring the cardiac myocytes' mechanical properties. Atomic force microscopy (AFM) was used, which characterises the cellular mechanical properties at a nanoscale precision. The Hertz model, the most common model in contact mechanics, was applied to the experimental data and an elastic modulus was determined by analysing the relationship between the AFM indentation force and the depth. To determine the Hertz model appropriateness accurately, the contribution of the viscous properties, the cell adherence and the elastic modulus extracting method were examined. The elastic moduli were 48.08 ± 2.26 kPa and 55.67 ± 2.56 kPa, respectively, with two different evaluation approaches. The cardiac myocyte exhibited a nonlinear elastic behaviour since the elastic modulus determined by the Hertz model was not constant in the different indentation depths. Furthermore, the viscous dissipation was negligible; therefore the mechanical behaviour of this cell type can be well described by appropriate hyperelastic models.

Silica nanoparticles (NPs) modified by imidazole, carboxyl and phenol groups were designed and synthesised. The particles were characterised by Fourier transform infrared spectroscopy, thermogravimetric analysis techniques, scanning electron microscopy and atomic absorption spectroscopy. Studies on superoxide dismutase (SOD) and catalase-like activities of the NPs show that the NPs have both a high catalase-like activity with a 100% conversion rate of H₂O₂ and SOD activity with IC₅₀ = 0.023 mg/ml, exhibiting the activity level of 10 U/ml biological SOD.

A design for improving gene transfection efficiency, which provides simple fabrication, low voltage and power consumptions, and easy implementation is developed; this design entails combining high and low electric fields, adjusting the voltage, using different numbers of pulses with varying durations, and different types of buffers with differing conductivities. The human embryonic kidney 293 (293T) cells were used. It was shown that a combination of two units of high electric field (1600 V/cm) for 0.6 ms and three units of low electric field (800 V/cm) for 1.2 ms is the optimum combination. This combination yielded a survival rate greater than 70% and a transfection rate of approximately 45%. The transfection rate of this combination was 80–100% greater than that obtained using two pulses, and the transfection rate obtained using two pulses was 40–50% greater than that obtained using single pulses. However, the survival rate decreases when the pulse duration is considerably long, even for low electric fields; therefore the number of pulses and their durations should be limited. The hypoosmolar buffer yielded the largest transfection rate. It was shown that the conductivity of the buffer solution is an important parameter, with the appropriate value ranging within 1.0–3.6 mS/cm. The transfection rate of the 293T cells using a cytoporation buffer could be enhanced by adding potassium ions in concentration lower than 2 μg/ml.

Fabrication of the anodic metals nanorod, especially Ti (titanium) nanorod arrays (Ti-NRAs), has attracted increasing attention in recent years. In this reported work, Ti-NRAs were prepared by applying a constant current of 200 mA under different anodisation conditions. The field emission scanning electron microscopy results showed that the density of the Ti-NRAs could be periodically tuned by the conditions of electrochemical anodisation. A possible formation mechanism is proposed to demonstrate the periodical tuning of the Ti-NRAs' density by the electrochemical anodisation time. This well-controlled synthesis approach may shed light on the fabrication of similar nanostructures of other metal materials.

Bifunctional magnetic-fluorescent Fe₃O₄@SiO₂@ZnS nanocomposites were synthesised by a chemical deposition method. The Fe₃O₄ magnetic nanoparticles as the core were obtained by means of a solvothermal reaction with SiO₂ as the shell. ZnS particles were linked to Fe₃O₄@SiO₂ core–shell nanostructures. The morphology and properties of the resultant Fe₃O₄@SiO₂@ZnS nanocomposites were investigated by X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, a vibration sample magnetometer and fluorescence microscopy. The results showed that bead-like structures were built from numerous Fe₃O₄@SiO₂@ZnS microspheres with an average size of 250 nm. The saturation magnetisation (M _s) value of Fe₃O₄@SiO₂@ZnS nanocomposites was 22.41 emu/g at room temperature. Furthermore, a strong blue light emission was observed from the nanocomposites under UV light irradiation. The combination of magnetic and fluorescent properties may lead to Fe₃O₄@SiO₂@ZnS nanocomposites having a variety of potential applications in the field of biomedicine, such as bioimaging and cell separation.

Based on the non-local Euler beam theory, the nonlinear dynamic stability of single-walled carbon nanotubes (SWCNTs) embedded in an elastic medium including the thermal effects is presented. The nonlinear dynamic equations and the boundary conditions of the SWCNTs are obtained by using the Hamilton variation principle. By adopting the Galerkin procedure, the governing nonlinear partial differential equation is converted into a nonlinear ordinary differential equation, and then the incremental harmonic balance method is applied to obtain the principal unstable regions of the SWCNTs. In the numerical examples, the effects of the thermal loads, the non-local parameters and the elastic medium on the nonlinear dynamic stability, respectively, are discussed.

A multi-gate n-type In_0.53Ga_0.47As metal oxide semiconductor field effect transistor is fabricated using the gate first self-aligned method and air-bridge technology with an 8 nm thick Al₂O₃ oxide layer. By scaling the gate length down to 200 nm, the effect of two different source/drain doping concentrations on device parameters such as threshold voltage, I _on/I _off ratio and subthreshold swing were investigated at room temperature. Increasing the value of the source/drain doping concentration revealed an enhancement in all investigated parameters. Sheet resistance and contact resistance values were improved as well. The negative shift in threshold voltage for shorter gate lengths was observed for both source/drain concentrations; however, the shift in threshold voltage was less (∼0.4 V) for the higher source/drain doping concentration.

Presented is a facile route to synthesise mesoporous nickel silicate coated on carbon nanotubes (CNTs) with a larger hole based on the mesoporous silica coated on the CNTs, the pore size of the mesoporous silica coated on the CNTs was enlarged from 2.72 to 7.8 nm after a hydrothermal reaction with nickel ions. Compared with other work for expanding the size of the pore, the authors’ presented method is low cost, simple and highly efficient. More importantly, this method shows great potential in applying other types of mesoporous materials such as SBA-15 and so on, all of which indicate that both the mesoporous nickel silicate coated on the CNTs and the mesoporous silica coated on the CNTs could serve as good candidates for adsorption on the organic pollutants.

Dip-pen nanolithography (DPN), based on atomic force microscope (AFM) system, is an effective method for nanoscale science and engineering and the potential applications of DPN feature in the fields of nanomechanics, nanomaterials, nanobiotechnology and nanomedicine and combined dynamic mode DPN, rather than the often used contact mode DPN or the tapping mode DPN, becomes an important tool for the creation of nanodots with the direct writing method of depositing the ink onto the hard silicon surface at the predetermined position with a very high resolution, which is presented in the corresponding experiments. For a better nanolithography quality of the nanodot, the nanolithography process, under the optimised process parameters, is accomplished once without the intermediate scan imaging process as much as possible. In addition, the size of the nanodots subsequently decreases with the increase of the number of the nanodots in the case of the AFM tip dipping in ink once. Consequently, for the creation of a nanodot within the controllable mass, the measurement scheme about the deposition mass of ink, theoretically analysed and experimentally achieved in the aspect of quantification, is also proposed in this Letter.

Three-dimensional cellulose gel was prepared by a crosslinking of the cellulose chains using epichlorohydrin in the presence of the NH₄OH, and the TiO₂ nanoparticles which were fixed on the surface of cellulose gel to form microcrystalline cellulose gel/nanoTiO₂ composites (MCC-TiO₂). The composites were characterised by means of X-ray diffraction, thermogravimetric analysis and scanning electron microscopy, respectively. The composites showed an efficient removal of methyl orange (MO) from their aqueous solution, and a two-step mechanism is involved. At first, the MO molecules were enriched on the surface of the MCC-TiO₂ by absorption, and then they were degraded there via photocatalysis, and the degradation of the adsorbed MO promoted the further adsorption of MO from the solution. After 30 min, 94% of MO was removed, and the MCC-TiO₂ can be cleaned by itself and reused without additional treatments.

Nanoparticles of acidic cesium salt of Preyssler by a one-step solid-state reaction at room temperature, were synthesised and characterised by Fourier transform infrared spectroscopy, titration, inductively coupled plasma and transmission electron microscopy (TEM), respectively. These uniform nanoparticles showed an average size of 2–10 nm. Multi-walled carbon nanotubes (MWCNTs) were synthesised by the catalytic chemical vapour deposition method and used as nanostructured porous supports for the immobilisation of the nanoparticles of the acidic cesium salt of Preyssler. The TEM image showed a bamboo-like structure with inner and outer diameters of about 20 and 35 nm, respectively. The modification of the MWCNTs by the synthesised nanoparticles was successfully achieved via the impregnation method. The infrared analysis showed that the basic structure of Preyssler is preserved and left intact. The TEM images also showed an endohedral functionalisation of the MWCNTs.

Highly luminescent CdSe quantum dots (QDs) with narrow spectra were synthesised by the reaction of CdCl₂·2.5H₂O, Se and hydrazine hydrate (N₂H₄·H₂O), respectively, in water and in the presence of 3-mercaptopropionic acid as the stabiliser. The effects of the experimental conditions, including the refluxing time and the selenium to cadmium molar ratio, on the luminescent properties of the obtained QDs have been investigated. Furthermore, the obtained QDs were characterised by UV–vis absorption spectra, photoluminescence (PL) spectra, X-ray powder diffraction and transmission electron microscopy, respectively. The results showed that the proposed method led to the formation of the cubic CdSe QDs with a narrow fluorescence full-width at half-maximum (47 nm) and a high PL quantum yield (up to 16%), respectively.

By using the electrocatalytic property of the nanomaterials and the molecular recognition characteristic of neutral red (NR), a new modified electrode was fabricated by electropolymerising the NR onto the surface of the multiwalled carbon nanotubes modified glassy carbon electrode, which exhibited a good electrocatalytic activity for folic acid (FA). The results of experiments showed that a good linear relationship between the reductive peak current of FA and its concentration was in the range of 6.25 × 10⁻⁷–5.00 × 10⁻⁵ mol/l with a detection limit of 1.37 × 10⁻⁷ mol/l in the optimal conditions. The recovery ratio was in the range of 99.3 ∼ 103.2%. The composite film modified electrode exhibited an excellent stability with a simple fabrication, which established a solid foundation for the practical applications.

Silica/polydopamine/silver (SiO₂/PD/Ag) nanoparticles (NPs) with a core–shell–satellite structure were fabricated and the mechanisms of their antibacterial activity were investigated. In this reported work, the results of the reactive oxygen species (ROS) assays, the deoxyribonucleic acid (DNA) damage assays and a cell morphology observation confirmed that Vibrio natriegens, a gram negative bacterium and Bacillus subtilis, a gram positive bacterium could be inhibited by the NPs. Gram negative bacteria exhibited more sensitivity towards the Ag NPs because these NPs were associated with penetration into the cytoplasm, with the subsequent local interaction of Ag with the cell components; thus, causing damages to the cells. SiO₂/PD/Ag NPs produced ROS which caused damage to the DNA leading to the suppression of transcription as detected by a reporter gene assay. Furthermore, ROS induced membrane damage was determined by transmission electron microscopy. Thus, the mechanisms of antibacterial activity were interpreted more precisely by using the aforementioned experiments. The results revealed that the production of ROS and damage to the membrane were the two major mechanisms of the bactericidal action of SiO₂/PD/Ag NPs; thus, these NPs could be employed as effective antifouling agents.

Nickel–chromium (NiCr) thin film acted as a terahertz (THz) absorption layer in uncooled infrared (IR) microbolometers operated in the THz spectral range. Nanoscale NiCr thin films with different thicknesses were deposited on the diaphragms of 320 × 240 IR focal plane arrays (IRFPAs). The experiments suggested that the THz absorption of NiCr film increased with the increased frequency. Absorption for a lower frequency decreased whereas that for a higher frequency increased with the decreased film thickness. Optimised absorption for different spectral ranges was achieved by adjusting the NiCr film thickness. A 30 nm NiCr film provided the largest absorption in 0.5–1.5 THz whereas an 8 nm NiCr film showed the greatest contribution in 2–2.5 THz. The THz absorption characteristics of the pixel membrane structure in the IRFPAs coupled with a thin metallic film were modelled and analysed. A good agreement was obtained between the calculations and the measurements.