Assembly of tobacco mosaic virus into fibrous and macroscopic bundled arrays mediated by surface aniline polymerization

In vitro biological activities of the flexible and virus nanoparticle-decorated silk fibroin-based films

Flexible films were prepared from silk fibroin (SF) and gelatin (GA) with a presence of glycerol (Gly), followed by water vapor annealing to achieve water-insoluble matrices. The blended SF/GA/Gly films were chemically conjugated with tobacco mosaic virus (TMV), either native (TMV-wt) or genetically modified with Arg-Gly-Asp (RGD) sequences (TMV-rgd), to improve cellular responses. The attachment and proliferation of L929 cells on TMV-decorated films were improved, possibly due to enhanced surface roughness. The cellular responses were pronounced with TMV-rgd, due to the proper decoration of RGD, which is an integrin recognition motif supporting cell binding. However, the biological results were inconclusive for human primary cells because of an innate slow growth kinetic of the cells. Additionally, the cells on SF/GA/Gly films were greater populated in S and G2/M phase, and the cell cycle arrest was notably increased in the TMV-conjugated group. Our findings revealed that the films modified with TMV were cytocompatible and the cellular responses were significantly enhanced when conjugated with its RGD mutants. The biological analysis on the cellular mechanisms in response to TMV is further required to ensure the safety concern of the biomaterials toward clinical translation.

Hollow Tobacco Mosaic Virus Coat Protein Assisted Self-Assembly of One-Dimensional Nanoarchitectures

Herein, an efficient strategy to fabricate well-organized one-dimensional (1D) inorganic nanostructures is demonstrated by utilizing the hollow tobacco mosaic virus coat protein (TMVCP) as a restrictive template. Considering the advantages of the unique hollow structure and the dynamic self-assembly attribute of TMVCP, foreign nano-objects are successfully encapsulated and conveniently assembled into highly organized 1D chainlike structures in the cavity of the TMVCP multimer (TMV disk). Different kinds of functional nanoparticles, such as gold nanoparticles (AuNPs) and silver sulfide quantum dots (Ag₂S QDs), are used to demonstrate the successful construction of ordered 1D nanochains in high yields. Notably, binary nanochains of such different kinds of nanoparticles are also constructed through co-assembling the TMV disk-coated AuNPs and Ag₂S QDs. Further, the TMV-assisted AuNP nanochains are grown into the 1D nanowires through in situ Au deposition owing to the spatial confinement of the TMVCP cavity. Together, our findings indicate that the TMV-assisted self-assembly approach, resulting in higher yields and better controllability over the other reported studies based on directly mineralizing the metal architectures in the TMV nanorods, provides enormous potential toward the fabrication of highly complex hybrid-metal nanostructures.

Some Important Issues of the Commercial Production of 1-D Nano-PANI

One-dimensional polyaniline nano-materials (1-D nano-PANI) have great promise applications in supercapacitors, sensors and actuators, electrochromic devices, anticorrosive coatings, and other nanometer devices. Consequently, commercial production of 1-D nano-PANI at large-scale needs to be quickly developed to ensure widespread usage of this material. Until now, approaches—including hard template methods, soft template methods, interfacial polymerization, rapid mixing polymerization, dilute polymerization, and electrochemical polymerization—have been reported to be used to preparation of this material. Herein, some important issues dealing with commercial production of 1-D nano-PANI are proposed based on the complexity of the synthetic process, its characters, and the aspects of waste production and treatment in particular. In addition, potential solutions to these important issues are also proposed.

Tobacco Mosaic Virus-Functionalized Mesoporous Silica Nanoparticles, a Wool-Ball-like Nanostructure for Drug Delivery

The design of versatile tools to improve cell targeting and drug delivery in medicine has become increasingly pertinent to nanobiotechnology. Biological and inorganic nanocarrier drug delivery systems are being explored, showing advantages and disadvantages in terms of cell targeting and specificity, cell internalization, efficient payload delivery, and safety profiles. Combining the properties of a biological coating on top of an inorganic nanocarrier, we hypothesize that this hybrid system would improve nanoparticle-cell interactions, resulting in enhanced cell targeting and uptake properties compared to the bare inorganic nanocarrier. Toward this goal, we engineered a hierarchical assembly featuring the functionalization of cargo-loaded mesoporous silica nanoparticles (MSNPs) with tobacco mosaic virus (TMV) as a biological coating. The MSNP functions as a delivery system because the porous structure enables high therapeutic payload capacity, and TMV serves as a biocompatible coating to enhance cell interactions. The resulting MSNP@TMV nanohybrids have a wool-ball-like appearance and demonstrate enhanced cell uptake, hence cargo delivery properties. The MSNP@TMV have potential for medical applications such as drug delivery, contrast agent imaging, and immunotherapy.

Mussel-Inspired Polydopamine Coating on Tobacco Mosaic Virus: One-Dimensional Hybrid Nanofibers for Gold Nanoparticle Growth

One-dimensional (1D) hybrid nanofibers with surface-deposited gold nanoparticles (AuNPs) have been fabricated by self-assembly of rod-like tobacco mosaic virus (TMV) with mussel-inspired polymerization of dopamine and in situ reduction of gold ion, providing a method for sensing the endocytic pathway of nanomaterial.

Adoption of the 2A Ribosomal Skip Principle to Tobacco Mosaic Virus for Peptide Display

Plant viruses are suitable as building blocks for nanomaterials and nanoparticles because they are easy to modify and can be expressed and purified using plants or heterologous expression systems. Plant virus nanoparticles have been utilized for epitope presentation in vaccines, for drug delivery, as nanospheres and nanowires, and for biomedical imaging applications. Fluorescent protein fusions have been instrumental for the tagging of plant virus particles. The monomeric non-oxygen-dependent fluorescent protein iLOV can be used as an alternative to green fluorescent protein. In this study, the iLOV sequence was genetically fused either directly or via a glycine-serine linker to the C-terminus of the Tobacco mosaic virus (TMV) coat protein (CP) and also carried an N-terminal Foot-and-mouth disease virus (FMDV) 2A sequence. Nicotiana benthamiana plants were inoculated with recombinant viral vectors and a systemic infection was achieved. The presence of iLOV fusion proteins and hybrid particles was confirmed by western blot analysis and transmission electron microscopy. Our data suggest that TMV-based vectors are suitable for the production of proteins at least as large as iLOV when combined with the FMDV 2A sequence. This approach allowed the simultaneous production of foreign proteins fused to the CP as well as free CP subunits.

Helical plant viral nanoparticles-bioinspired synthesis of nanomaterials and nanostructures

Viral nanotechnology is revolutionizing the biomimetic and bioinspired synthesis of novel nanomaterials. Bottom-up nanofabrication by self-assembly of individual molecular components of elongated viral nanoparticles (VNPs) and virus-like particles (VLPs) has resulted in the production of superior materials and structures in the nano(bio)technological fields. Viral capsids are attractive materials, because of their symmetry, monodispersity, and polyvalency. Helical VNPs/VLPs are unique prefabricated nanoscaffolds with large surface area to volume ratios and high aspect ratios, and enable the construction of exquisite supramolecular nanostructures. This review discusses the genetic and chemical modifications of outer, inner, and interface surfaces of a viral protein cage that will almost certainly lead to the development of superior next-generation targeted drug delivery and imaging systems, biosensors, energy storage and optoelectronic devices, therapeutics, and catalysts.

Tailoring the Self-Assembly Behaviors of Recombinant Tobacco Mosaic Virus by Rationally Introducing Covalent Bonding at the Protein-Protein Interface

Understanding the self-assembly mechanism of protein building blocks is important to realize the control of protein structures and functionalities. Here, for the first time, four different self-assembly behaviors of tobacco mosaic virus coat protein are reported from 2D disk arrays, disk stacks to 3D tube stacks, and tube bundles, respectively, with rationally mutated cysteines at 1, 3, and 103 sites.

Combining Protein Cages and Polymers: from Understanding Self-Assembly to Functional Materials

Protein cages, such as viruses, are well-defined biological nanostructures which are highly symmetrical and monodisperse. They are found in various shapes and sizes and can encapsulate or template non-native materials. Furthermore, the proteins can be chemically or genetically modified giving them new properties. For these reasons, these protein structures have received increasing attention in the field of polymer-protein hybrid materials over the past years, however, advances are still to be made. This Viewpoint highlights the different ways polymers and protein cages or their subunits have been combined to understand self-assembly and create functional materials.

Viral-templated gold/polypyrrole nanopeapods for an ammonia gas sensor

One-dimensional gold/polypyrrole (Au/PPy) nanopeapods were fabricated using a viral template: M13 bacteriophage. The genetically modified filamentous virus displayed gold-binding peptides along its length, allowing selective attachment of gold nanoparticles (Au NPs) under ambient conditions. A PPy shell was electropolymerized on the viral-templated Au NP chains forming nanopeapod structures. The PPy shell morphology and thickness were controlled through electrodeposition potential and time, resulting in an ultra-thin conductive polymer shell of 17.4 ± 3.3 nm. A post-electrodeposition acid treatment was used to modify the electrical properties of these hybrid materials. The electrical resistance of the nanopeapods was monitored at each assembly step. Chemiresistive ammonia (NH3) gas sensors were developed from networks of the hybrid Au/PPy nanostructures. Room temperature sensing performance was evaluated from 5 to 50 ppmv and a mixture of reversible and irreversible chemiresistive behavior was observed. A sensitivity of 0.30%/ppmv was found for NH3 concentrations of 10 ppmv or less, and a lowest detection limit (LDL) of 0.007 ppmv was calculated. Furthermore, acid-treated devices exhibited an enhanced sensitivity of 1.26%/ppmv within the same concentration range and a calculated LDL of 0.005 ppmv.

Design of virus-based nanomaterials for medicine, biotechnology, and energy

This review provides an overview of recent developments in "chemical virology." Viruses, as materials, provide unique nanoscale scaffolds that have relevance in chemical biology and nanotechnology, with diverse areas of applications. Some fundamental advantages of viruses, compared to synthetically programmed materials, include the highly precise spatial arrangement of their subunits into a diverse array of shapes and sizes and many available avenues for easy and reproducible modification. Here, we will first survey the broad distribution of viruses and various methods for producing virus-based nanoparticles, as well as engineering principles used to impart new functionalities. We will then examine the broad range of applications and implications of virus-based materials, focusing on the medical, biotechnology, and energy sectors. We anticipate that this field will continue to evolve and grow, with exciting new possibilities stemming from advancements in the rational design of virus-based nanomaterials.

Nanostructured conducting polymers for energy applications: towards a sustainable platform

Recently, there has been tremendous progress in the field of nanodimensional conducting polymers with the objective of tuning the intrinsic properties of the polymer and the potential to be efficient, biocompatible, inexpensive, and solution processable. Compared with bulk conducting polymers, conducting polymer nanostructures possess a high electrical conductivity, large surface area, short path length for ion transport and superior electrochemical activity which make them suitable for energy storage and conversion applications. The current status of polymer nanostructure fabrication and characterization is reviewed in detail. The present review includes syntheses, a deeper understanding of the principles underlying the electronic behavior of size and shape tunable polymer nanostructures, characterization tools and analysis of composites. Finally, a detailed discussion of their effectiveness and perspectives in energy storage and solar light harvesting is presented. In brief, a broad overview on the synthesis and possible applications of conducting polymer nanostructures in energy domains such as fuel cells, photocatalysis, supercapacitors and rechargeable batteries is described.

Biomimetic and Bioinspired Synthesis of Nanomaterials/Nanostructures

In recent years, due to its unparalleled advantages, the biomimetic and bioinspired synthesis of nanomaterials/nanostructures has drawn increasing interest and attention. Generally, biomimetic synthesis can be conducted either by mimicking the functions of natural materials/structures or by mimicking the biological processes that organisms employ to produce substances or materials. Biomimetic synthesis is therefore divided here into "functional biomimetic synthesis" and "process biomimetic synthesis". Process biomimetic synthesis is the focus of this review. First, the above two terms are defined and their relationship is discussed. Next different levels of biological processes that can be used for process biomimetic synthesis are compiled. Then the current progress of process biomimetic synthesis is systematically summarized and reviewed from the following five perspectives: i) elementary biomimetic system via biomass templates, ii) high-level biomimetic system via soft/hard-combined films, iii) intelligent biomimetic systems via liquid membranes, iv) living-organism biomimetic systems, and v) macromolecular bioinspired systems. Moreover, for these five biomimetic systems, the synthesis procedures, basic principles, and relationships are discussed, and the challenges that are encountered and directions for further development are considered.

Photonics and plasmonics go viral: self-assembly of hierarchical metamaterials

Sizing and shaping of mesoscale architectures with nanoscale features is a key opportunity to produce the next generation of higher-performing products and at the same time unveil completely new phenomena. This review article discusses recent advances in the design of novel photonic and plasmonic structures using a biology-inspired design. The proteinaceous capsids from viruses have long been discovered as platform technologies enabling unique applications in nanotechnology, materials, bioengineering, and medicine. In the context of materials applications, the highly organized structures formed by viral capsid proteins provide a 3D scaffold for the precise placement of plasmon and gain materials. Based on their highly symmetrical structures, virus-based nanoparticles have a high propensity to self-assemble into higher-order crystalline structures, yielding hierarchical hybrid materials. Recent advances in the field have led to the development of virus-based light harvesting systems, plasmonic structures for application in high-performance metamaterials, binary nanoparticle lattices, and liquid crystalline arrays for sensing or display technologies. There is still much that could be explored in this area, and we foresee that this is only the beginning of great technological advances in virus-based materials for plasmonics and photonics applications.

Viral nano-hybrids for innovative energy conversion and storage schemes

Typical rod-like viruses (the Tobacco Mosaic Virus (TMV) and the Bacteriophage M13) are biological nanostructures that couple a 1D mono-dispersed morphology with a precisely defined topology of surface spaced and orthogonal reactive domains. These biogenic scaffolds offer a unique alternative to synthetic nano-platforms for the assembly of functional molecules and materials. Spatially resolved 1D arrays of inorganic-organic hybrid domains can thus be obtained on viral nano-templates resulting in the functional arrangement of photo-triggers and catalytic sites with applications in light energy conversion and storage. Different synthetic strategies are herein highlighted depending on the building blocks and with a particular emphasis on the molecular design of viral-templated nano-interfaces holding great potential for the dream-goal of artificial photosynthesis.

Directed Growth of Virus Nanofilaments on a Superhydrophobic Surface

The evaporation of single droplets of colloidal tobacco mosaic virus (TMV) nanoparticles on a superhydrophobic surface with a hexagonal pillar-pattern results in the formation of coffee-ring type residues. We imaged surface features by optical, scanning electron, and atomic force microscopies. Bulk features were probed by raster-scan X-ray nanodiffraction. At ∼100 pg/μL nanoparticle concentration, the rim of the residue connects to neighboring pillars via fibrous extensions containing flow-aligned crystalline domains. At ∼1 pg/μL nanoparticle concentration, nanofilaments of ≥80 nm diameter and ∼20 μm length are formed, extending normal to the residue-rim across a range of pillars. X-ray scattering is dominated by the nanofilament form-factor but some evidence for crystallinity has been obtained. The observation of sheets composed of stacks of self-assembled nanoparticles deposited on pillars suggests that the nanofilaments are drawn from a structured droplet interface.

Enhancing Antibody Response against Small Molecular Hapten with Tobacco Mosaic Virus as a Polyvalent Carrier

Virus nanoparticles (VNPs) have been applied as carrier proteins for effective vaccine development. In this paper, we report the usage of tobacco mosaic virus (TMV) as a carrier for the display of the small molecule estriol (E3), a weakly immunogenic hapten. A highly efficient copper (I)-catalyzed azide-alkyne cycloaddition reaction (CuAAC) was performed for the conjugation of E3 onto TMV capsid at tyrosine (Tyr) 139, by which the antigen density could be controlled. The immune properties of these constructs were evaluated in mice. We found that a strong and long-term antibody response was elicited by conjugating a high density of small molecular haptens on TMV through an oligo(ethylene glycol) (OEG) linker, likely due to the effective activation of B-cells. This study suggests that TMV can serve as a promising platform to induce strong humoral immune responses and that the optimized conjugation strategy was critical to produce high quality antibodies.

Storing energy in plastics: a review on conducting polymers & their role in electrochemical energy storage

This review article on conducting polymers discusses the background & theory behind their conductivity, the methods to nano-engineer special morphologies & recent contributions to the field of energy (e.g.supercapacitors, batteries and fuel cells).

Single-molecule force spectroscopy study on the mechanism of RNA disassembly in tobacco mosaic virus

To explore the disassembly mechanism of tobacco mosaic virus (TMV), a model system for virus study, during infection, we have used single-molecule force spectroscopy to mimic and follow the process of RNA disassembly from the protein coat of TMV by the replisome (molecular motor) in vivo, under different pH and Ca(2+) concentrations. Dynamic force spectroscopy revealed the unbinding free-energy landscapes as that at pH 4.7 the disassembly process is dominated by one free-energy barrier, whereas at pH 7.0 the process is dominated by one barrier and that there exists a second barrier. The additional free-energy barrier at longer distance has been attributed to the hindrance of disordered loops within the inner channel of TMV, and the biological function of those protein loops was discussed. The combination of pH increase and Ca(2+) concentration drop could weaken RNA-protein interactions so much that the molecular motor replisome would be able to pull and disassemble the rest of the genetic RNA from the protein coat in vivo. All these facts provide supporting evidence at the single-molecule level, to our knowledge for the first time, for the cotranslational disassembly mechanism during TMV infection under physiological conditions.

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.

Polyaniline nanotubes with rectangular-hollow-core and its self-assembled surface decoration: high conductivity and dielectric properties

Self-assembled and surface decorated PANI nanotubes with rectangular hallow core with high electrical and dielectric properties.

Facile method for large scale alignment of one dimensional nanoparticles and control over myoblast orientation and differentiation

A facile and robust method to align one-dimensional (1D) nanoparticles (NPs) in large scale has been developed. Using flow assembly, representative rod-like nanoparticles, including tobacco mosaic virus (TMV), gold nanorods, and bacteriophage M13, have been aligned inside glass tubes by controlling flow rate and substrate surface properties. The properties of 1D NPs, such as stiffness and aspect ratio, play a critical role in the alignment. Furthermore, these hierarchically organized structures can be used to support cell growth and control the cell orientation and morphology. When C2C12 myoblasts were cultured on surfaces coated with aligned TMV, we found that nanoscale topographic features were critical to guide the cell orientation and myogenic differentiation. This method can therefore be used in the fabrication of complex assemblies with 1D NPs and have wide applications in tissue engineering, sensing, electronics, and optical fields.

Tobacco mosaic virus rods and spheres as supramolecular high-relaxivity MRI contrast agents

To compensate for the low sensitivity of magnetic resonance imaging (MRI), nanoparticles have been developed to deliver high payloads of contrast agents to sites of disease. Here, we report the development of supramolecular MRI contrast agents using the plant viral nanoparticle tobacco mosaic virus (TMV). Rod-shaped TMV nanoparticles measuring 300×18 nm were loaded with up to 3,500 or 2,000 chelated paramagnetic gadolinium (III) ions selectively at the interior (iGd-TMV) or exterior (eGd-TMV) surface, respectively. Spatial control is achieved through targeting either tyrosine or carboxylic acid side chains on the solvent exposed exterior or interior TMV surface. The ionic T₁ relaxivity per Gd ion (at 60 MHz) increases from 4.9 mM^-1s^-1 for free Gd(DOTA) to 18.4 mM^-1s^-1 for eGd-TMV and 10.7 mM^-1s^-1 for iGd-TMV. This equates to T₁ values of ~ 30,000 mM^-1s^-1 and ~ 35,000 mM^-1s^-1 per eGd-TMV and iGd-TMV nanoparticle. Further, we show that interior-labeled TMV rods can undergo thermal transition to form 170 nm-sized spherical nanoparticles containing ~ 25,000 Gd chelates and a per particle relaxivity of almost 400,000 mM^-1s^-1 (15.2 mM^-1s^-1 per Gd). This work lays the foundation for the use of TMV as a contrast agent for MRI.

Virus-poly(3,4-ethylenedioxythiophene) biocomposite films

Virus-poly(3,4-ethylenedioxythiophene) (virus-PEDOT) biocomposite films are prepared by electropolymerizing 3,4-ethylenedioxythiophene (EDOT) in aqueous electrolytes containing 12 mM LiClO(4) and the bacteriophage M13. The concentration of virus in these solutions, [virus](soln), is varied from 3 to 15 nM. A quartz crystal microbalance is used to directly measure the total mass of the biocomposite film during its electrodeposition. In combination with a measurement of the electrodeposition charge, the mass of the virus incorporated into the film is calculated. These data show that the concentration of the M13 within the electropolymerized film, [virus](film), increases linearly with [virus](soln). The incorporation of virus particles into the PEDOT film from solution is efficient, resulting in a concentration ratio of [virus](film):[virus](soln) ≈ 450. Virus incorporation into the PEDOT causes roughening of the film topography that is observed using scanning electron microscopy and atomic force microscopy (AFM). The electrical conductivity of the virus-PEDOT film, measured perpendicular to the plane of the film using conductive tip AFM, decreases linearly with virus loading, from 270 μS/cm for pure PEDOT films to 50 μS/cm for films containing 100 μM virus. The presence on the virus surface of displayed affinity peptides did not significantly influence the efficiency of incorporation into virus-PEDOT biocomposite films.

Au nanocrystals grown on a better-defined one-dimensional tobacco mosaic virus coated protein template genetically modified by a hexahistidine tag

In this paper, tobacco mosaic virus (TMV) coated protein (CP) was genetically modified by introducing a hexahistidine tag into it for a well-defined one-dimensional template, on which Au nanocrystals (NCs) were grown. The results showed that genetic modification could not only ameliorate the one-dimensional structure of the template, but also improve the growth density of Au NCs on the template. This indicated that genetic modification could be an effective method to modulate the structure of the TMVCP template-based nanocomposites allowing for a broader application of them.

Superlattice of rodlike virus particles formed in aqueous solution through like-charge attraction

Rodlike tobacco mosaic virus (TMV) has been found to assemble into a 2D superlattice in aqueous solution with hexagonally packed structures in the presence of Ba(2+) through like-charge attraction whereas lower-Z divalent ions such as Zn(2+), Cd(2+), Mg(2+), and Ca(2+) induce only liquidlike ordering. The molar ratio between Ba(2+) and TMV is a crucial parameter in the formation of the superlattice. There is a critical molar ratio of Ba(2+) to TMV at which TMV exhibits a transition from a nonordered colloidal state to an ordered crystalline state. It is also found that the superlattice is formed regardless of the pH and TMV concentration within the range studied.

In situ small-angle X-ray scattering analysis of palladium nanoparticle growth on tobacco mosaic virus nanotemplates

We present an examination of palladium (Pd) nanoparticle growth on genetically modified tobacco mosaic virus (TMV1cys) nanotemplates via in situ small-angle X-ray scattering (SAXS). Specifically, we examine the role of the TMV1cys templates in Pd nanoparticle formation through the electroless reduction of Pd precursor by a chemical reducing agent as compared to identical conditions in the absence of the TMV1cys templates. We show that in the presence of TMV1cys, the viral nanotemplates provide preferential growth sites for Pd nanoparticle formation, as no measurable Pd particle growth was observed in the bulk solution. In situ SAXS confirmed that particle formation was due to the rapid adsorption of Pd atoms onto the TMV1cys templates at the very early stage of mixing, rather than adsorption of particles formed in the bulk solution. Importantly, Pd nanoparticles were significantly smaller and more uniform as compared to particle formation in the absence of TMV1cys. The Pd nanoparticle coating density was tunable based on Pd precursor concentration. Finally, we show that Pd particle growth on the TMV1cys templates was highly rapid, and complete within 33 s for most samples, in contrast to slower Pd particle growth in the absence of TMV templates. We envision that the results presented here will be valuable in furthering the fundamental understanding of the role of viral nanotemplates in particle formation, as well as of their utility in a wide range of applications.

Hybrid macroscopic fibers from the synergistic assembly between silica and filamentous viruses

In this work, we report the elaboration of macroscopic hybrid virus-silica fibers. By using a silicate sol as inorganic precursor combined with the filamentous fd virus, well-dispersed hybrid fibers are obtained in solution. These macroscopic fd-silica fibers exhibit a narrow distribution of their diameter, while their length is at the millimeter scale. A scenario of the morphosynthesis is proposed to account for the formation of these high aspect ratio hybrid fibers.

Role of hexahistidine in directed nanoassemblies of tobacco mosaic virus coat protein

A common challenge in nanotechnology is the fabrication of materials with well-defined nanoscale structure and properties. Here we report that a genetically engineered tobacco mosaic virus (TMV) coat protein (CP), to which a hexahistidine (His) tag was incorporated, can self-assemble into disks, hexagonally packed arrays of disks, stacked disks, helical rods, fibers, and elongated rafts. The insertion of a His tag to the C-terminus of TMV-CP was shown to significantly affect the self-assembly in comparison to the wild type, WT-TMV-CP. Furthermore, the His tag interactions attributed to the alternative self-assembly of His-TMV-CP can be controlled through ethanol and nickel-nitrilotriacetic acid (Ni-NTA) additions as monitored with atomic force microscopy.

Self-assembly of virus particles on flat surfaces via controlled evaporation

Dynamic self-assembly of nonvolatile solutes via controlled solvent evaporation has been exploited as a simple route to create a variety of hierarchically assembled structures. In this work, two glass slides were used to form a confined space in which a solution of a rodlike nanoparticle, tobacco mosaic virus (TMV), was evaporated to create large-scale stripe patterns. The height and width of the stripes are dependent on the TMV concentration. The large-scale-patterned surfaces can be applied to control surface hydrophobicity and direct the growth of bone marrow stromal cells. We systematically studied the effects of stripe width and height on surface hydrophobicity using optical microscopy, atomic force microscopy, and contact angle measurements. This technique offers a facile approach to form 2D patterns on a large surface from a wide range of proteins as well as other biomacromolecules.