Avoiding the Trust Deficit: Public Engagement, Values, the Precautionary Principle and the Future of Nanotechnology

Debates about the regulatory requirements surrounding the introduction of nanotechnology products have, at least in Australia, remained largely within disciplinary boundaries and industry and academic circles. This paper argues for a more interdisciplinary and inclusive upstream debate about the introduction of ethical, regulatory and legal frameworks that may avoid the loss of public trust that has characterised the introduction of many new technologies in the past. Insights from risk-perception theory and research are used to introduce the notion of risk as narrative as a framework for action. This paper suggests three main strategies for moving forward; drawing insights from the “trust gap” experiences of other new technologies; the application of the active form of the precautionary principle; and, the creation of nano-futures that meet both community and industry values through effective public engagement.     

Characterisation of silver nanoparticles synthesised by Bacillus thuringiensis as a nanobiopesticide for insect pest control

Nanotechnology has become one of the most promising new approaches for pest control in recent years. In this research, biocompatible silver nanoparticles (Btk-AgNPs) were synthesised by using the entomopathogenic bacterium, Bacillus thuringiensis kurstaki (Btk) as a low-cost and eco-friendly production system. The AgNP samples exhibited a brownish-yellow colour that is characteristic for silver nanoparticles synthesis. Btk-synthesised AgNPs were produced using both the supernatant and pellet of Bt culture at various concentrations and AgNP particles were characterised by UV-Vis spectrophotometer and Dynamic Light Scattering (DLS). The variation of hydrodynamic diameter (D_h) and UV-Vis spectra of silver particles produced by various concentration of culture showed that production of AgNPs was maximised when using 20% for either supernatant or pellet treatments of Bt of culture and the size of particles was around 85?nm for both. The insecticidal efficacy of Btk-synthesised AgNPs against larvae of the cabbage looper, Trichoplusia ni (Hübner) and black cutworm, Agrotis ipsilon (Hufnagel) was tested. Results demonstrated that the treatments of either Btk-synthesised AgNP(s) made with Bt supernatant or Btk-synthesised AgNP(p) using Bt pellet were found to be significantly more virulent toward larvae of T. ni than to A. ipsilon.     

In Vivo Nano-imaging of Membrane Dynamics in Metastatic Tumor Cells Using Quantum Dots

Changes in membrane morphology and membrane protein dynamics based on its fluidity are critical for cancer metastasis. However, this subject has remained unclear, because the spatial precision of previous in vivo imaging has been limited to the micrometer level and single molecule imaging is impossible. Here, we have imaged the membrane dynamics of tumor cells in mice with a spatial precision of 7–9 nm under a confocal microscope. A metastasis-promoting factor on the cell membrane, protease-activated receptor 1 (PAR1), was labeled with quantum dots conjugated with an anti-PAR1 antibody. Movements of cancer cells and PAR1 during metastasis were clearly observed in vivo. Images used to assess PAR1 dynamics were taken of representative cells for four stages of metastasis; i.e. cancer cells far from blood vessels in tumor, near the vessel, in the bloodstream, and adherent to the inner vascular surface in the normal tissues near tumor were photographed. The diffusion constant of PAR1 in static cells far from tumor blood vessels was smaller than in moving cells near the vessels and in the bloodstream. The diffusion constant of cells adhering to the inner vascular surface in the normal tissues was also very small. Cells formed membrane protrusion during migration. The PAR1 diffusion constant on these pseudopodia was greater than in other membrane regions in the same cell. Thus, the dynamics of PAR1 movement showed that membrane fluidity increases during intravasation, reaches a peak in the vessel, decreases during extravasation, and is also higher at locally formed pseudopodia.     

Nonlinear vibrations of pre- and post-buckled lipid supramolecular micro/nano-tubules via nonlocal strain gradient elasticity theory

The unique geometry with high surface ratio makes lipid micro/nano-tubules as an excellent self-assembled supramolecular structure in various biological applications such as controllable release systems and drug delivery. In the present study, the size-dependent nonlinear vibrations of axially loaded lipid micro/nano tubules associated with the both prebuckling and postbuckling domains are explored comprehensively. To accomplish this purpose, the nonlocal strain gradient theory of elasticity including simultaneously two entirely different features of size dependency is utilized within the framework of the third-order shear deformable beam model. With the aid of Hamilton's principle, the non-classical governing differential equations of motion are established incorporating the nonlinear prebuckling deformations and the large postbuckling deflections. At the end, the Galerkin method in conjunction with an improved perturbation technique is employed to initiate explicit analytical expressions for nonlocal strain gradient nonlinear frequency of pre- and post-buckled lipid micro/nano-tubules. It is seen that by taking the nonlocal size effect into consideration, the influence of geometrical parameters of the lipid micro/nano-tubule on the nonlinear vibration characteristics within the both prebuckling and postbuckling domains decreases and the frequency-deflection curves are more close to each other. However, the strain gradient size dependency has an opposite effect and leads to increase the gap between the frequency-deflection curves of axially compressed lipid micro/nano-tubules with different geometrical parameters.     

Micro and nanotechnological tools for study of RNA

Micro and nanotechnologies have originally contributed to engineering, especially in electronics. These technologies enable fabrication and assembly of materials at micrometer and nanometer scales and the manipulation of nano-objects. The power of these technologies has now been exploited in analyzes of biologically relevant molecules. In this review, the use of micro and nanotechnological tools in RNA research is described.     

Silver nanoparticles as a new generation of antimicrobials

Silver has been in use since time immemorial in the form of metallic silver, silver nitrate, silver sulfadiazine for the treatment of burns, wounds and several bacterial infections. But due to the emergence of several antibiotics the use of these silver compounds has been declined remarkably. Nanotechnology is gaining tremendous impetus in the present century due to its capability of modulating metals into their nanosize, which drastically changes the chemical, physical and optical properties of metals. Metallic silver in the form of silver nanoparticles has made a remarkable comeback as a potential antimicrobial agent. The use of silver nanoparticles is also important, as several pathogenic bacteria have developed resistance against various antibiotics. Hence, silver nanoparticles have emerged up with diverse medical applications ranging from silver based dressings, silver coated medicinal devices, such as nanogels, nanolotions, etc.     

Plant-based green synthesis of silver nanoparticles and its effective role in abiotic stress tolerance in crop plants

The development of effective and environmentally friendly methods for the green synthesis of nanoparticles (NPs) is a critical stage in the field of nanotechnology. Silver nanoparticles (AgNPs) are significant due to their unique physical, chemical, and biological properties, as well as their numerous applications. Physical, chemical, and green synthesis approaches can all be used to produce AgNPs; however, synthesis using biological precursors, particularly plant-based green synthesis, has shown outstanding results. In recent years, owing to a combination of frequent droughts, unusual rainfall, salt-affected areas, and high temperatures, climate change has changed several ecosystems. Crop yields have decreased globally as a result of these changes in the environment. Green synthesized AgNPs role in boosting antioxidant defense mechanisms, methylglyoxal (MG) detoxification, and developing tolerance for abiotic stress-induced oxidative damage has been thoroughly described in plant species over the last decade. Although various studies on abiotic stress tolerance and metallic nanoparticles (NPs) in plants have been conducted, but the details of AgNPs mediated abiotic stress tolerance have not been well summarized. Therefore, the plant responses to abiotic stress need to be well understood and to apply the gained knowledge to increase stress tolerance by using AgNPs for crop plants. In this review, we outlined the green synthesis of AgNPs extracted from plant extract. We also have updates on the most important accomplishments through exogenous application of AgNPs to improve plant tolerance to drought, salinity, low and high-temperature stresses.     

Design rules for nanomedical engineering: from physical virology to the applications of virus-based materials in medicine

Physical virology seeks to define the principles of physics underlying viral infections, traditionally focusing on the fundamental processes governing virus assembly, maturation, and disassembly. A detailed understanding of virus structure and assembly has facilitated the development and analysis of virus-based materials for medical applications. In this Physical Virology review article, we discuss the recent developments in nanomedicine that help us to understand how physical properties affect the in vivo fate and clinical impact of (virus-based) nanoparticles. We summarize and discuss the design rules that need to be considered for the successful development and translation of virus-based nanomaterials from bench to bedside.     

Computational Soft Nanotechnology with Mesodyn

The simulation of microstructures on a scale 1–1000?nm is a typical problem in colloid and polymer science, and this is also the realm of modern computational “soft nanotechnology”. Accordingly, computational methods rely heavily on time-honoured approaches for calculating the thermodynamical stability of complex mixtures. We describe such approaches in the framework of MesoDyn, a general purpose software package for field-based simulations methods, such as the polymer mean-field model for microphase formation and the Poisson–Boltzmann model for electrostatic interactions. The paper concludes with a small review of examples of application: the formation of microscopic structures in block copolymer bulk solutions, block copolymer melt structures on surfaces (thin films) and structure formation in tiny polymer surfactant droplets (polymersomes). The method works quite well in all cases where a mean-field model is appropriate, but it is a challenge to extend the simulations to systems in which specific correlations are important.