Biotemplating rod-like viruses for the synthesis of copper nanorods and nanowires

Screening of novel peptides that specifically interact with vitamin D bound biocomplex proteins

The majority of the vitamin D that is present in the blood binds to vitamin D binding protein (VDBP) and circulates in the form of a complex (VDBP-Complex). Knowing the level of vitamin D in the body is crucial for vitamin D-related treatments so that the right dosage of vitamin D can be given. In other words, it is essential to distinguish between the protein VDBP and the complex form bound to vitamin D. As a novel way for the detection of VDBP-Complex, a more effective phage display methodology was applied in this study along with the addition of two approaches. In order to screen a sequence specific to the target only, the pre-binding method and after-binding method were performed. VDBP-Complex was directly coated on the petri dishes. In order to select phages that specifically bind to the VDBP-Complex, random phages were attached, and selected by 7 times of biopanning. Individual DNA sequences were analyzed for each biopanning to find specific peptide sequences for VDBP-Complex. The affinity of binding phages was verified by ELISA assay using an anti-M13 antibody. The phage having a sequence of SFTKTSTFTWRD (called as M3) has shown the highest binding affinity to VDBP-Complex. As a result of the removal test of VDBP-Complex using magnetic beads conjugated with M3 peptide, it was confirmed that significant decrease of VDBP-Complex. The unique characteristic of the M3 sequence was confirmed through a sequence-modified peptide (SFT motif). That is, it is expected that the M3 peptide may be used to determine the vitamin D levels in the blood.

Fabrication and Molecular Modeling of Navette-Shaped Fullerene Nanorods Using Tobacco Mosaic Virus as a Nanotemplate

To date, metallization studies have been performed with the nanometer-scale template, Tobacco Mosaic Virus (TMV). Here we show that fullerenes as well can be deposited on TMV coat protein in a controlled manner. Two methods were followed for the coating process. First, underivatized fullerene was dispersed in different solvents to bring the underivatized fullerene and wild-type TMV together. Improved depositions were obtained with the fullerene dicarboxylic derivative synthesized via the Bingel method. The form of the coating was analyzed by transmission electron microscopy. Our results demonstrate that the coating efficiency with the carboxy derivative was much better compared to the underivatized fullerene. The goal of coupling a carbon nanoparticle to a biological molecule, the viral coat of TMV, was achieved with the carboxy derivative of fullerene, resulting in the production of navette-shaped nanorods. The interactions between carboxyfullerenes and TMV were investigated through modeling with computational simulations and Gaussian-based density functional theory (DFT) calculations using the Gaussian09 program package. The theoretical calculations supported the experimental findings. This inexpensive and untroublesome method promises new fullerene hybrid nanomaterials in particular shapes and structures.

Plant Virus Nanoparticles for Anti-cancer Therapy

Plant virus nanoparticles (VNPs) are inexpensive to produce, safe, biodegradable and efficacious as treatments. The applications of r plant virus nanoparticles range from epitope carriers for vaccines to agents in cancer immunotherapy. Both VNPs and virus-like particles (VLPs) are highly immunogenic and are readily phagocytosed by antigen presenting cells (APCs), which in turn elicit antigen processing and display of pathogenic epitopes on their surfaces. Since the VLPs are composed of multiple copies of their respective capsid proteins, they present repetitive multivalent scaffolds which aid in antigen presentation. Therefore, the VLPs prove to be highly suitable platforms for delivery and presentation of antigenic epitopes, resulting in induction of more robust immune response compared to those of their soluble counterparts. Since the tumor microenvironment poses the challenge of self-antigen tolerance, VLPs are preferrable platforms for delivery and display of self-antigens as well as otherwise weakly immunogenic antigens. These properties, in addition to their diminutive size, enable the VLPs to deliver vaccines to the draining lymph nodes in addition to promoting APC interactions. Furthermore, many plant viral VLPs possess inherent adjuvant properties dispensing with the requirement of additional adjuvants to stimulate immune activity. Some of the highly immunogenic VLPs elicit innate immune activity, which in turn instigate adaptive immunity in tumor micro-environments. Plant viral VLPs are nontoxic, inherently stable, and capable of being mass-produced as well as being modified with antigens and drugs, therefore providing an attractive option for eliciting anti-tumor immunity. The following review explores the use of plant viruses as epitope carrying nanoparticles and as a novel tools in cancer immunotherapy.

Self-Assembly of DNA molecules in magnetic Fields

In this work, a rich variety of self-assembled DNA patterns were obtained in the magnetic field. Herein, atomic force microscopy (AFM) was utilized to investigate the effects of the concentration of DNA solution, intensity and direction of magnetic field and modification of mica surface by different cations on the self-assembly of DNA molecules. It was found that owning to the change of the DNA concentration, even under the same magnetic field, the DNA self-assembly results were different. Thein situtest results showed that the DNA self-assembly in an magnetic field was more likely to occur in liquid phase than in gas phase. In addition, whether in a horizontal or vertical magnetic field, a single stretched dsDNA was obtained in a certain DNA concentration and magnetic field intensity. Besides, the modification of cations on the mica surface significantly increased the force between the DNA molecules and mica surface, and further changed the self-assembly of DNA molecules under the action of magnetic field.

Bio-Templating: An Emerging Synthetic Technique for Catalysts. A Review

In the last few years, researchers have focused their attention on the synthesis of new catalyst structures based on or inspired by nature. Biotemplating involves the transfer of biological structures to inorganic materials through artificial mineralization processes. This approach offers the main advantage of allowing morphological control of the product, as a template with the desired morphology can be pre-determined, as long as it is found in nature. This way, natural evolution through millions of years can provide us with new synthetic pathways to develop some novel functional materials with advantageous properties, such as sophistication, miniaturization, hybridization, hierarchical organization, resistance, and adaptability to the required need. The field of application of these materials is very wide, covering nanomedicine, energy capture and storage, sensors, biocompatible materials, adsorbents, and catalysis. In the latter case, bio-inspired materials can be applied as catalysts requiring different types of active sites (i.e., redox, acidic, basic sites, or a combination of them) to a wide range of processes, including conventional thermal catalysis, photocatalysis, or electrocatalysis, among others. This review aims to cover current experimental studies in the field of biotemplating materials synthesis and their characterization, focusing on their application in heterogeneous catalysis.

Frontiers in Bioengineering and Biotechnology: Plant Nanoparticles for Anti-Cancer Therapy

Naturally occurring viral nanomaterials have gained popularity owing to their biocompatible and biodegradable nature. Plant virus nanoparticles (VNPs) can be used as nanocarriers for a number of biomedical applications. Plant VNPs are inexpensive to produce, safe to administer and efficacious as treatments. The following review describes how plant virus architecture facilitates the use of VNPs for imaging and a variety of therapeutic applications, with particular emphasis on cancer. Examples of plant viruses which have been engineered to carry drugs and diagnostic agents for specific types of cancer are provided. The drug delivery system in response to the internal conditions is known as stimuli response, recently becoming more applicable using plant viruses based VNPs. The review concludes with a perspective of the future of plant VNPs and plant virus-like particles (VLPs) in cancer research and therapy.

Tumor-targeting inorganic nanomaterials synthesized by living cells

Inorganic nanomaterials (NMs) have shown potential application in tumor-targeting theranostics, owing to their unique physicochemical properties. Some living cells in nature can absorb surrounding ions in the environment and then convert them into nanomaterials after a series of intracellular/extracellular biochemical reactions. Inspired by that, a variety of living cells have been used as biofactories to produce metallic/metallic alloy NMs, metalloid NMs, oxide NMs and chalcogenide NMs, which are usually automatically capped with biomolecules originating from the living cells, benefitting their tumor-targeting applications. In this review, we summarize the biosynthesis of inorganic nanomaterials in different types of living cells including bacteria, fungi, plant cells and animal cells, accompanied by their application in tumor-targeting theranostics. The mechanisms involving inorganic-ion bioreduction and detoxification as well as biomineralization are emphasized. Based on the mechanisms, we describe the size and morphology control of the products via the modulation of precursor ion concentration, pH, temperature, and incubation time, as well as cell metabolism by a genetic engineering strategy. The strengths and weaknesses of these biosynthetic processes are compared in terms of the controllability, scalability and cooperativity during applications. Future research in this area will add to the diversity of available inorganic nanomaterials as well as their quality and biosafety.

Engineering Tobacco Mosaic Virus and Its Virus-Like-Particles for Synthesis of Biotemplated Nanomaterials

Biomolecules are increasingly attractive templates for the synthesis of functional nanomaterials. Chief among them is the plant tobacco mosaic virus (TMV) due to its high aspect ratio, narrow size distribution, diverse biochemical functionalities presented on the surface, and compatibility with a number of chemical conjugations. These properties are also easily manipulated by genetic modification to enable the synthesis of a range of metallic and non-metallic nanomaterials for diverse applications. This article reviews the characteristics of TMV and related viruses, and their virus-like particle (VLP) derivatives, and how these may be manipulated to extend their use and function. A focus of recent efforts has been on greater understanding and control of the self-assembly processes that drive biotemplate formation. How these features have been exploited in engineering applications such as, sensing, catalysis, and energy storage are briefly outlined. While control of VLP surface features is well-established, fewer tools exist to control VLP self-assembly, which limits efforts to control template uniformity and synthesis of certain templated nanomaterials. However, emerging advances in synthetic biology, machine learning, and other fields promise to accelerate efforts to control template uniformity and nanomaterial synthesis enabling more widescale industrial use of VLP-based biotemplates.

Green Synthesis of Reduced Graphene Oxide-Supported Palladium Nanoparticles by Coleus amboinicus and Its Enhanced Catalytic Efficiency and Antibacterial Activity

Novel reduced graphene oxide-supported palladium nanoparticles (RGO-PN) were synthesized under ultrasonication, a method that utilizes Coleus amboinicus as a bio-reduction agent. Green synthesized RGO-PN nanoparticles with a crystallite size in the range of 40–50 nm were confirmed in X-ray diffraction (XRD) spectra. RGO-PN show an absorption peak at 220 nm while reduced graphene oxide (RGO) shows its maximal absorbance at 210 nm. The scanning electron microscope image revealed that 40-nm-sized spherical-shaped palladium nanoparticles stick well to reduced graphene oxide sheets, which is consistent and correlated well with the XRD pattern. Moreover, a high-resolution morphological image of RGO-PN100 was obtained by TEM analysis, which shows the anchoring of palladium nanoparticles (PN) on RGO nanosheets. Green synthesized RGO-PN100 nanoparticles from Coleus amboinicus show better reduction kinetics for 4-nitrophenol at 40 min, suggesting that RGO-PN prepared from Coleus amboinicus serve as an excellent catalytic reducing agent. Furthermore, they show remarkable antibacterial activity against Escherichia coli (ATCC 25922). Thus, green synthesized RGO-supported palladium nanoparticles demonstrated that enhanced catalytic activity and antibacterial activity both play an important role in the environmental and medical disciplines.

Lipid Nanotubes as an Organic Template for an Electrically Conductive Gold Nanostructure Network

We demonstrate an approach to fabricate a gold nanowire network that presents a macroscopic electrical conductivity based on a lipid nanotube (LNT) template with attached gold nanoparticles. The poor electrical conductivity that we have previously faced was overcome by centrifugation and resuspension of gold nanoparticle solution for removing stabilizing agents, which increased the density of gold nanoparticles on the LNTs. An additional electroless metal plating further enhanced their contacts at nanoscale. Thanks to these procedures, the sheet resistance was improved by 11 orders of magnitude. As a proof of principle, transparent conductive films were fabricated with these gold nanowires, which exhibited sheet resistance of maximum 70 Ω/□ and transmittance of 50-75% in visible light.

Tuning the Product Selectivity of the Cu Hollow Fiber Gas Diffusion Electrode for Efficient CO2 Reduction to Formate by Controlled Surface Sn Electrodeposition

The efficient CO₂ electrochemical reduction reaction (CO₂RR) relies not only on the development of selective/active catalysts but also on the advanced electrode configuration to solve the critical issue of poor CO₂ mass transport and derived sluggish cathodic reaction kinetics. In this work, to achieve a favorable reaction rate and product selectivity, we designed and synthesized an asymmetric porous Cu hollow fiber gas diffusion electrode (HFGDE) with controlled Sn surface electrodeposition. The HFGDE derived from the optimal Sn electrodeposition condition exhibited a formate Faradaic efficiency (FE) of 78% and a current density of 88 mA cm^-2 at -1.2 V versus reversible hydrogen electrode, which are more than 2 times higher than those from the pristine Cu HFGDE. The achieved performance outperformed most of the other Sn-based GDEs, indicating the creation of sufficient contact among CO₂, electrolyte, and electrode catalyst through the design of the hollow fiber pore structure and catalytic active sites. The enhancement of formate production selectivity and the suppression of the hydrogen by-product were attributed to the optimized ratio of SnO_x species on the electrode surface. The best performance was seen in the HFGDE with the highest Sn²⁺/Sn⁴⁺ (120 s deposition), likely due to the modulating effect of the Cu substrate via electron donation with Sn species. The selectivity control strategy developed in the asymmetric HFGDE provides an efficient and facile method to stimulate selective electrochemical reactions in which the gas-phase reactant with low solubility is involved.

The phage display of Bacillus subtilis Lipase A significantly enhances catalytic activity due to altered nanoscale distribution in colloidal solution

Screening libraries of mutant proteins by phage display is now relatively common. However, one unknown factor is how the bacteriophage scaffold itself influences the properties of the displayed protein. This communication evaluates the effect of solution parameters on the catalytic activity of phage displayed Bacillus subtilis Lipase A (BSLA), compared to the free enzyme in solution. While the pH- and temperature-activity profiles of BSLA were not intrinsically affected by phage display, the nanoscale distribution of BSLA within the micellar assay buffer was. This lead to a pronounced increase of activity of phage-BSLA relative to the free enzyme, owing to the accumulation of phage-BSLA at the substrate-rich micelles. Considering this result obtained for BSLA, caution is warranted and similar effects should be considered when selecting other enzymes/proteins by phage display, as the activity of the displayed protein may differ from that of the free protein.

Controlled Self-Assembly of λ-DNA Networks with the Synergistic Effect of a DC Electric Field

Large-scale and morphologically controlled self-assembled λ-DNA networks were successfully constructed by the synergistic effect of a DC electric field. The effect of DNA concentration, direction, and intensity of the electric field, even the modification of the mica surface using Mg²⁺ on the characteristics of the as-prepared DNA networks, were investigated in detail by atomic force microscopy (AFM). It was found that the horizontal electric field was more advantageous to the formation of DNA networks with more regular structures. At the same concentration, the height of DNA network was not affected significantly by the intensity change of the horizontal electric field. The modification of Mg²⁺ on mica surface increased the aggregation of DNA molecules, which contributed to the morphological change of the DNA networks. Furthermore, DNA molecules were obviously stretched in both horizontal and vertical electric fields at low DNA concentrations.

The 2018 Nobel Prize in Chemistry: phage display of peptides and antibodies

One-half of the 2018 Nobel Prize in Chemistry was awarded jointly to George P. Smith and Sir Gregory P. Winter "for the phage display of peptides and antibodies". This feature article summarizes significant achievements leading to the development of phage display of peptides and antibodies, where a bacteriophage is genetically modified to display peptides and proteins, with the primary aim of producing new biopharmaceuticals. These significant achievements are proven to be useful for the development of phage-based bioassays and biosensors.

Direct synthesis of ultralong platinum nanowires with prominent electrocatalytic performance using lanreotide biotemplate

Due to the dependence on the morphology, size and composition of Pt-based nanomaterials on their catalytic properties, rational design can improve the utilization efficiency and catalytic performance of Pt. As inspired by this, the ultralong Pt nanowires (ULPtNWs) with a diameter of 25 nm were prepared by a mild, green and direct peptide mediated biological template method. Impressively, ULPtNWs with a large electrochemical active surface area (57.2 m² g^-1) were obtained, exhibiting that the peak current density for the methanol oxidation was approximately three-fold better than commercial Pt/C catalyst owing to the high aspect ratio (1.6 × 10³ or more). Additionally, the excellent poison resistance of the product was demonstrated, which can be attributed to the high (111) plane. These enhancements indicate that ULPtNWs as a promising catalyst have broad application prospects in the field of direct methanol fuel cells or other electrocatalysis.

Highly adjustable 3D nano-architectures and chemistries via assembled 1D biological templates

Porous metal nanofoams have made significant contributions to a diverse set of technologies from separation and filtration to aerospace. Nonetheless, finer control over nano and microscale features must be gained to reach the full potential of these materials in energy storage, catalytic, and sensing applications. As biologics naturally occur and assemble into nano and micro architectures, templating on assembled biological materials enables nanoscale architectural control without the limited chemical scope or specialized equipment inherent to alternative synthetic techniques. Here, we rationally assemble 1D biological templates into scalable, 3D structures to fabricate metal nanofoams with a variety of genetically programmable architectures and material chemistries. We demonstrate that nanofoam architecture can be modulated by manipulating viral assembly, specifically by editing the viral surface coat protein, as well as altering templating density. These architectures were retained over a broad range of compositions including monometallic and bi-metallic combinations of noble and transition metals of copper, nickel, cobalt, and gold. Phosphorous and boron incorporation was also explored. In addition to increasing the surface area over a factor of 50, as compared to the nanofoam's geometric footprint, this process also resulted in a decreased average crystal size and altered phase composition as compared to non-templated controls. Finally, templated hydrogels were deposited on the centimeter scale into an array of substrates as well as free standing foams, demonstrating the scalability and flexibility of this synthetic method towards device integration. As such, we anticipate that this method will provide a platform to better study the synergistic and de-coupled effects between nano-structure and composition for a variety of applications including energy storage, catalysis, and sensing.

The Robust Self-Assembling Tubular Nanostructures Formed by gp053 from Phage vB_EcoM_FV3

The recombinant phage tail sheath protein, gp053, from Escherichia coli infecting myovirus vB_EcoM_FV3 (FV3) was able to self-assemble into long, ordered and extremely stable tubular structures (polysheaths) in the absence of other viral proteins. TEM observations revealed that those protein nanotubes varied in length (~10–1000 nm). Meanwhile, the width of the polysheaths (~28 nm) corresponded to the width of the contracted tail sheath of phage FV3. The formed protein nanotubes could withstand various extreme treatments including heating up to 100 °C and high concentrations of urea. To determine the shortest variant of gp053 capable of forming protein nanotubes, a set of N- or/and C-truncated as well as poly-His-tagged variants of gp053 were constructed. The TEM analysis of these mutants showed that up to 25 and 100 amino acid residues could be removed from the N and C termini, respectively, without disturbing the process of self-assembly. In addition, two to six copies of the gp053 encoding gene were fused into one open reading frame. All the constructed oligomers of gp053 self-assembled in vitro forming structures of different regularity. By using the modification of cysteines with biotin, the polysheaths were tested for exposed thiol groups. Polysheaths formed by the wild-type gp053 or its mutants possess physicochemical properties, which are very attractive for the construction of self-assembling nanostructures with potential applications in different fields of nanosciences.

Synthesis and modelling of the mechanical properties of Ag, Au and Cu nanowires

The recent interest to nanotechnology aims not only at device miniaturisation, but also at understanding the effects of quantised structure in materials of reduced dimensions, which exhibit different properties from their bulk counterparts. In particular, quantised metal nanowires made of silver, gold or copper have attracted much attention owing to their unique intrinsic and extrinsic length-dependent mechanical properties. Here we review the current state of art and developments in these nanowires from synthesis to mechanical properties, which make them leading contenders for next-generation nanoelectromechanical systems. We also present theories of interatomic interaction in metallic nanowires, as well as challenges in their synthesis and simulation.

Protein cage assembly across multiple length scales

Within the materials science community, proteins with cage-like architectures are being developed as versatile nanoscale platforms for use in protein nanotechnology. Much effort has been focused on the functionalization of protein cages with biological and non-biological moieties to bring about new properties of not only individual protein cages, but collective bulk-scale assemblies of protein cages. In this review, we report on the current understanding of protein cage assembly, both of the cages themselves from individual subunits, and the assembly of the individual protein cages into higher order structures. We start by discussing the key properties of natural protein cages (for example: size, shape and structure) followed by a review of some of the mechanisms of protein cage assembly and the factors that influence it. We then explore the current approaches for functionalizing protein cages, on the interior or exterior surfaces of the capsids. Lastly, we explore the emerging area of higher order assemblies created from individual protein cages and their potential for new and exciting collective properties.

Dual-Functionalized Virus-Gold Nanoparticle Clusters for Biosensing

Metallic nanoscale 3D architectures concentrate electromagnetic energy at precise spatial locations to enable sensing and photocatalysis applications. We have developed solution-based methods to reproducibly fabricate 3D gold nanostructures useful as efficient surface-enhanced Raman spectroscopy (SERS) biosensors. Virus capsids were recruited as templates to assemble gold nanoparticles on their surfaces at well-defined locations to prepare the nanoscale 3D structures. Cowpea mosaic virus (CPMV) and its variants were selected as specific templates due to their high symmetry, scalability, and stability, which have proven useful in materials science applications. While the methods described herein were optimized for the CPMV capsids, they also provide a useful starting point for researchers who are working toward the nanoassembly of metal nanoparticles on other protein scaffolds.

Chitin Liquid-Crystal-Templated Oxide Semiconductor Aerogels

Chitin nanocrystals have been used as a liquid crystalline template to fabricate layered oxide semiconductor aerogels. Anisotropic chitin liquid crystals are transformed to sponge-like aerogels by hydrothermally cross-linked gelation and lyophilization-induced solidification. The hydrothermal gelation of chitin aqueous suspensions then proceeds with peroxotitanate to form hydrogel composites that recover to form aerogels after freeze-drying. The homogeneous peroxotitanate/chitin composites are calcined to generate freestanding titania aerogels that exhibit the nanostructural integrity of layered chitin template. Our extended investigations show that coassembling chitin nanocrystals with other metal-based precursors also yielded semiconductor aerogels of perovskite BaTiO₃ and CuO_x nanocrystals. The potential of these materials is great to investigate these chitin sponges for biomedicine and these semiconductor aerogels for photocatalysis, gas sensing, and other applications. Our results present a new aerogel templating method of highly porous, ultralight materials with chitin liquid crystals.

Protein-Mediated Biotemplating on the Nanoscale

Purified proteins offer a homogeneous population of biological nanoparticles, equipped in many cases with specific binding sites enabling the directed self-assembly of envisaged one-, two- or three-dimensional arrays. These arrays may serve as nanoscale biotemplates for the preparation of novel functional composite materials, which exhibit potential applications, especially in the fields of nanoelectronics and optical devices. This review provides an overview of the field of protein-mediated biotemplating, focussing on achievements made throughout the past decade. It is comprised of seven sections designed according to the size and configuration of the protein-made biotemplate. Each section describes the design and size of the biotemplate, the resulting hybrid structures, the fabrication methodology, the analytical tools employed for the structural analysis of the hybrids obtained, and, finally, their claimed/intended applications and a feasibility demonstration (whenever available). In conclusion, a short assessment of the overall status of the achievements already made vs. the future challenges of this field is provided.

High Quality Bioreplication of Intricate Nanostructures from a Fragile Gecko Skin Surface with Bactericidal Properties

The external epithelial surfaces of plants and animals are frequently carpeted with small micro- and nanostructures, which broadens their adaptive capabilities in challenging physical habitats. Hairs and other shaped protuberances manage with excessive water, light contaminants, predators or parasites in innovative ways. We are interested in transferring these intricate architectures onto biomedical devices and daily-life surfaces. Such a project requires a very rapid and accurate small-scale fabrication process not involving lithography. In this study, we describe a simple benchtop biotemplating method using shed gecko lizard skin that generates duplicates that closely replicate the small nanotipped hairs (spinules) that cover the original skin. Synthetic replication of the spinule arrays in popular biomaterials closely matched the natural spinules in length. More significantly, the shape, curvature and nanotips of the synthetic arrays are virtually identical to the natural ones. Despite some small differences, the synthetic gecko skin surface resisted wetting and bacterial contamination at the same level as natural shed skin templates. Such synthetic gecko skin surfaces are excellent platforms to test for bacterial control in clinical settings. We envision testing the biocidal properties of the well-matched templates for fungal spores and viral resistance in biomedicine as well as co/multi-cultures.

Highly efficient redox-driven reversible color switching of dye molecules via hydrogenation/oxygenation

We report a novel reversible color switching system based on one-pot hydrogenation/oxygenation reactions over Pd/CeO_2-x catalysts and fast interconversion of thionine (TH⁺) and leuco thionine (LTH). Oxygen vacancies produced by Pd-catalyzed instant hydrogenation of CeO₂ and strong metal-support interaction (SMSI) could lead to fast color switching.

Comparative Study of Non-Enveloped Icosahedral Viruses Size

Now, as before, transmission electron microscopy (TEM) is a widely used technique for the determination of virions size. In some studies, dynamic light scattering (DLS) has also been applied for this purpose. Data obtained by different authors and using different methods could vary significantly. The process of TEM sample preparation involves drying on the substrate, which can cause virions to undergo morphology changes. Therefore, other techniques should be used for measurements of virions size in liquid, (i.e. under conditions closer to native). DLS and nanoparticle tracking analysis (NTA) provide supplementary data about the virions hydrodynamic diameter and aggregation state in liquid. In contrast to DLS, NTA data have a higher resolution and also are less sensitive to minor admixtures. In the present work, the size of non-enveloped icosahedral viruses of different nature was analyzed by TEM, DLS and NTA: the viruses used were the encephalomyocarditis virus (animal virus), and cauliflower mosaic virus, brome mosaic virus and bean mild mosaic virus (plant viruses). The same, freshly purified, samples of each virus were used for analysis using the different techniques. The results were compared with earlier published data and description databases. DLS data about the hydrodynamic diameter of bean mild mosaic virus, and NTA data for all examined viruses, were obtained for the first time. For all virus samples, the values of size obtained by TEM were less than virions sizes determined by DLS and NTA. The contribution of the electrical double layer (EDL) in virions hydrodynamic diameter was evaluated. DLS and NTA data adjusted for EDL thickness were in better agreement with TEM results.

Bio-inspired synthesis of metal nanomaterials and applications

This critical review focuses on recent advances in the bio-inspired synthesis of metal nanomaterials (MNMs) using microorganisms, viruses, plants, proteins and DNA molecules as well as their applications in various fields. Prospects in the design of bio-inspired MNMs for novel applications are also discussed.

Rapid, one-pot procedure to synthesise103Pd:Pd@Au nanoparticles en route for radiosensitisation and radiotherapeutic applications

Radioactive gold–palladium nanoparticles for radiotherapy.

Fabrication of nanoarchitectures templated by virus-based nanoparticles: strategies and applications

Biomolecular nanostructures in nature are drawing increasing interests in the field of materials sciences. As a typical group of them, virus-based nanoparticles (VNPs), which are nanocages or nanorods assembled from capsid proteins of viruses, have been widely exploited as templates to guide the fabrication of complex nanoarchitectures (NAs), because of their appropriate sizes (ca. 20-200 nm), homogeneity, addressable functionalization, facile modification via chemical and genetic routes, and convenient preparation. Foreign materials can be positioned in the inner cavity or on the outer surface of VNPs, through either direct synthesis or assembling preformed nanomaterials. Simultaneous use of the inner and outer space of VNPs facilitates integration of multiple functionalities in a single NA. This review briefly summarizes the strategies for fabrication of NAs templated by VNPs and wide applications of these NAs in fields of catalysis, energy, biomedicine, and nanophotonics, etc.

Production of platinum atom nanoclusters at one end of helical plant viruses

Platinum atom clusters (Pt nanoparticles, Pt-NPs) were produced selectively at one end of helical plant viruses, tobacco mosaic virus (TMV) and potato virus X (PVX), when platinum coordinate compounds were reduced chemically by borohydrides. Size of the platinum NPs depends on conditions of the electroless deposition of platinum atoms on the virus. Results suggest that the Pt-NPs are bound concurrently to the terminal protein subunits and the 5′ end of encapsidated TMV RNA. Thus, a special structure of tobacco mosaic virus and potato X virus particles with nanoparticles of platinum, which looks like a push-pin with platinum head and virus needle, was obtained. Similar results were obtained with ultrasonically fragmented TMV particles. By contrast, the Pt-NPs fully filled the central axial hole of in vitro assembled RNA-free TMV-like particles. We believe that the results presented here will be valuable in the fundamental understanding of interaction of viral platforms with ionic metals and in a mechanism of nanoparticles formation.

Designed 3D architectures of high-temperature superconductors

Self-supporting superconducting replicas of pasta shapes are reported, yielding products of differing 3D architectures. Functioning high-temperature superconductor wires are developed and refined from replicas of spaghetti, demonstrating a unique sol-gel processing technique for the design and synthesis of novel macroscopic morphologies of complex functional materials.

Insights into biogenic and chemical production of inorganic nanomaterials and nanostructures

The synthesis of inorganic nanomaterials and nanostructures by the means of diverse physical, chemical, and biological principles has been developed in recent decades. The nanoscale materials and structures creation continue to be an active area of researches due to the exciting properties of the resulting nanomaterials and their innovative applications. Despite physical and chemical approaches which have been used for a long time to produce nanomaterials, biological resources as green candidates that can replace old production methods have been focused in recent years to generate various inorganic nanoparticles (NPs) or other nanoscale structures. Cost-effective, eco-friendly, energy efficient, and nontoxic produced nanomaterials using diverse biological entities have been received increasing attention in the last two decades in contrast to physical and chemical methods owe using toxic solvents, generate unwanted by-products, and high energy consumption which restrict the popularity of these ways employed in nanometric science and engineering. In this review, the biosynthesis of gold, silver, gold-silver alloy, magnetic, semiconductor nanocrystals, silica, zirconia, titania, palladium, bismuth, selenium, antimony sulfide, and platinum NPs, using bacteria, actinomycetes, fungi, yeasts, plant extracts and also informational bio-macromolecules including proteins, polypeptides, DNA, and RNA have been reported extensively to mention the current status of the biological inorganic nanomaterial production. In other hand, two well-known wet chemical techniques, namely chemical reduction and sol-gel methods, used to produce various types of nanocrystalline powders, metal oxides, and hybrid organic-inorganic nanomaterials have presented.

Tools from viruses: bacteriophage successes and beyond

Viruses are ubiquitous and can infect any of the three existing cellular lineages (Archaea, Bacteria and Eukarya). Despite the persisting negative public perception of these entities, scientists learnt how to domesticate some of them. The study of molecular mechanisms essential to the completion of viral cycles has greatly contributed to deciphering fundamental processes in biology. Nowadays, viruses have entered the biotechnological era and numerous applications have already been developed. Viral-derived tools are used to manipulate genetic information, detect, diagnose, control and cure infectious diseases, or even design new structural assemblies. With the recent advances in the field of metagenomics, an overwhelming amount of information on novel viruses has become available. As current tools have been historically developed from a limited number of viruses, the potential of discoveries from new archaeal, bacterial and eukaryotic viruses may be limited only by our understanding of the multiple facets of viral cycles.