Rod-like Tobacco Mosaic Virus Research Articles

One-Dimensional Rod-like Tobacco Mosaic Virus Promotes Macrophage Polarization for a Tumor-Suppressive Microenvironment.

The phenotype of tumor-associated macrophages plays an important role in their function of regulating the tumor immune microenvironment. The M1-phenotype macrophages display tumor-killing and immune activating functions. Here we show that the tobacco mosaic virus (TMV), a rod-like plant virus, can polarize macrophages to an M1 phenotype and shape a tumor-suppressive microenvironment. RAW 264.7 cells and bone marrow derived-macrophages (BMDMs) can recognize TMV via Toll-like receptor-4, and then the MAPK and NF-κB signaling pathways are activated, leading to the production of pro-inflammatory factors. Furthermore, the in vivo assessments on a subcutaneous co-injection tumor model show that the TMV-polarized BMDMs shape a tumor-suppressive microenvironment, resulting in remarkable delay of 4T1 tumor growth. Another in vivo assessment on an established tumor model indicates the high tumor-metastasis-inhibiting capacity of TMV-polarized BMDMs. This work suggests a role for this plant virus in macrophage-mediated therapeutic approaches and provides a strategy for tumor immunotherapy.

Conjugating Peptides onto 1D Rodlike Bionanoparticles for Enhanced Activity against Gram-Negative Bacteria.

Gram-negative bacteria, which possess an impermeable outer membrane, are responsible for many untreatable infections. The lack of development of new relevant antibiotics for over 50 years has increased threats. Peptides are regarded as the most promising alternatives to antibiotics. However, since the activities of existing peptides are not yet comparable to those of current antibiotics, there is an urgent need to improve their antibacterial efficiencies. Herein, we conjugate peptides onto one-dimensional rod-like tobacco mosaic virus (TMV). The peptides on the obtained nanoparticles (peptide-TMV) are hundreds of times superior to free peptides in combating Gram-negative bacteria. Through morphology and gene detection of Escherichia coli, it was revealed that following peptide-TMV application, the high osmotic pressure related to membrane damage and the generated reactive oxygen species cause Escherichia coli's death. In addition, peptide-TMV causes a downregulation of biofilm-related genes, inhibiting biofilm formation. This work paves the way to combat Gram-negative bacteria-related infection.

Near-Infrared Chiral Plasmonic Microwires through Precision Assembly of Gold Nanorods on Soft Biotemplates

Directing the assembly of plasmonic nanoparticles into chiral superstructures has diverse applications including, chiroptical sensing, nonlinear optics, and biomedicine. Though soft template-mediated assemblies of both spherical and nonspherical gold nanoparticles have made significant progress, most approaches require sophisticated chemical synthesis or advanced methodologies. Besides, reports of structurally precise chiral plasmonic assemblies beyond nanoscale are limited. Here, we propose an efficient yet simple strategy to grow such precision assemblies up to mesoscale, which is beneficial for a broader community. Briefly, cationic gold nanorods (AuNRs) are allowed to systematically assemble along atomically precise, chiral, rodlike tobacco mosaic virus (TMV) particles via electrostatic attraction under ambient condition. This leads to spontaneous formation of helical hybrid microwires with high structural precision, as evidenced by cryogenic transmission electron microscopy and tomography. Resulting composite superstructures show a strong circular dichroism response at the plasmon wavelength of the AuNRs, which is supported by simulations using discrete dipole approximation. Further, chirality of the system is investigated at a single-microwire level using polarized dark-field scattering microscopy. An alternative chiral template, negatively charged colloidal cellulose nanocrystals, also arrange AuNRs into similar chiral microstructures. Thus, our report proposes a generic methodology to obtain chiral plasmonic response at the NIR region using inexpensive templates that will encourage the exploration of a wider range of nanoscale templates for creating hybrid mesostructures with emerging optoelectronic properties.

Bioinspired Artificial Tobacco Mosaic Virus with Combined Oncolytic Properties to Completely Destroy Multidrug-Resistant Cancer.

Although biomimetic virus-like strategies have been widely used in antitumor applications, construction of uniquely shaped virus-like agents and optimization of their specific morphological features to achieve diverse antitumor functions are worthwhile pursuits. Here, a novel strategy to construct an artificial tobacco mosaic virus (ATMV) that closely mimics the structure of the rod-like tobacco mosaic virus (TMV) is developed. The supramolecular array is self-assembled from small, repeated subunits of tailor-made capsid-mimicking dendrons onto RGD-modified single-walled carbon nanotube to construct the ATMVs with high structural stability. The ATMVs are tactfully designed with shielding, targeting, and arming approaches, including shielding the viruses against premature elimination, selectively targeting tumor tissue, and arming the viruses with oncolytic abilities. The elongated particles are concealed in blood until they arrived at a tumor site, then they induce robust composite oncolytic processes including cytomembrane penetration, endoplasmic reticulum disruption to cause Ca2+ release, chemotherapeutic delivery, and photothermal therapy. Excitingly, the ATMVs not only lyse primary infected cells, but permeate adjacent cells for secondary infection, spreading cell-to-cell and continuing to induce lysis even deep in solid tumors. This work inspires a uniquely shaped virus-like agent with tactically optimized oncolytic functions that completely defeated large drug-resistant colon tumor (LoVo/Adr, ≈500 mm3 ).

Covalent incorporation of tobacco mosaic virus increases the stiffness of poly(ethylene glycol) diacrylate hydrogels.

Hydrogels are versatile materials, finding applications as adsorbers, supports for biosensors and biocatalysts or as scaffolds for tissue engineering. A frequently used building block for chemically cross-linked hydrogels is poly(ethylene glycol) diacrylate (PEG-DA). However, after curing, PEG-DA hydrogels cannot be functionalized easily. In this contribution, the stiff, rod-like tobacco mosaic virus (TMV) is investigated as a functional additive to PEG-DA hydrogels. TMV consists of more than 2000 identical coat proteins and can therefore present more than 2000 functional sites per TMV available for coupling, and thus has been used as a template or building block for nano-scaled hybrid materials for many years. Here, PEG-DA (Mn = 700 g mol−1) hydrogels are combined with a thiol-group presenting TMV mutant (TMVCys). By covalent coupling of TMVCys into the hydrogel matrix via the thiol-Michael reaction, the storage modulus of the hydrogels is increased compared to pure PEG-DA hydrogels and to hydrogels containing wildtype TMV (wt-TMV) which is not coupled covalently into the hydrogel matrix. In contrast, the swelling behaviour of the hydrogels is not altered by TMVCys or wt-TMV. Transmission electron microscopy reveals that the TMV particles are well dispersed in the hydrogels without any large aggregates. These findings give rise to the conclusion that well-defined hydrogels were obtained which offer the possibility to use the incorporated TMV as multivalent carrier templates e.g. for enzymes in future studies.

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.

Shear flow induced long-range ordering of rod-like viral nanoparticles within hydrogel

Controlling the alignment of anisotropic nanoparticles within a three-dimensional (3D) environment over large-scale is still a challenge. In this paper, a facile method to align rod-like nanoparticles in hydrogel via shear flow to afford a long-range order is reported. The rod-like tobacco mosaic virus (TMV) was employed as a prototypical anisotropic particles in the study, and the shear force provided by the unidirectional flow of the precursor solution direct the alignment of TMVs, which could be quickly fixed through the fast sol-gel transition in situ. The degree of orientation and the distance between the TMV particles could be regulated by adjusting the concentration of hydrogels and TMVs. While the introduction of TMVs could reduce the degree of swelling of the hydrogel and help maintaining the mechanical strength of resultant hydrogels, both repulsion interaction and shear flow contributed synergistically to the assembly. This method does not require the usage of strong magnetic or electric fields, nor does it require the use of specialized lithography, thus offers a facile way to the fabrication of hydrogel materials with control of anisotropic structural features.

Hierarchical Self-Assembly of Responsive Organoplatinum(II) Metallacycle-TMV Complexes with Turn-On Fluorescence.

Here we report that the rod-like tobacco mosaic virus (TMV), having a negatively charged surface, can be assembled into three-dimensional micrometer-sized bundle-like superstructures via multiple electrostatic interactions with a positively charged molecular "glue", namely, a tetraphenylethylene (TPE)-based discrete organoplatinum(II) metallacycle (TPE-Pt-MC). Due to the nanoconfinement effect in the resultant TMV/TPE-Pt-MC complexes and the aggregation-induced emission (AIE) activity of the TPE units, these hierarchical architectures result in a dramatic fluorescence enhancement that not only provides evidence for the formation of novel metal-organic biohybrid materials but also represents an alternative to turn-on fluorescence. Moreover, the dissociation of these final constructs and subsequent release of individual virus have been achieved by disrupting the TPE-Pt-MC core using tetrabutylammonium bromide (TBAB). This strategy is also compatible with other protein-based nanoparticles such as bacteriophage M13 and ferritin, proving the generality of this approach. Hence, this research will open new routes for the fabrication of functional biohybrid materials involving metal-organic complexes and anisotropically shaped bionanoparticles.

Tobacco Mosaic Virus Functionalized Alginate Hydrogel Scaffolds for Bone Regeneration in Rats with Cranial Defect.

Plant viruses have been highlighted among material research due to their well-defined structures in nanoscale, monodispersity, stability, and chemical functionalities. Each of the thousands coat protein subunits on a viral nanoparticle can be homogeneously modified, chemically and genetically, with a functional ligand leading to a high-density and spatial distribution of ligands on each particle (multivalency). Previous reports from our group have evidenced that substrates coated with Tobacco mosaic virus (TMV) and its mutant promote early osteogenesis of mesenchymal stem cells (MSCs). We then fabricated a three-dimensional (3D) biopolymeric scaffold with rod-like TMV in the form of a sponge-like hydrogel for tissue engineering purposes. The hydrogel was functionalized with the cellular recognition peptide, arginine-glycine-aspartic acid (RGD), through an incorporation of an RGD mutant of TMV (TMV-RGD). The virus-functionalized hydrogel materials were shown to aid bone differentiation of MSCs in vitro. Herein, we performed an in vivo study based on the TMV and TMV-RGD hydrogels in Sprague-Dawley rats with cranial bone defects. This report substantiated the hypothesis that TMV-functionalized hydrogel scaffolds did not cause systemic toxicity when implanted in the defect site and that the TMV-based hydrogel platform can support cell localization and can be further optimized for bone regeneration and repair.

Temperature responsive 3D structure of rod-like bionanoparticles induced by depletion interaction

Herein, we show that rod-like tobacco mosaic virus (TMV) can self-assemble into 3D bundled structures in aqueous solution using azobenzene modified Pluronics F127 block copolymers (Azo-F127) to induce depletion. The structures are characterized by both transmission electron microscopy and dynamic light scattering. The self-assembly process can be controlled reversibly by temperature. The formation of Azo-F127 hard spheres during the self-assembly is the main cause of this phenomenon.

Dual stimuli-responsive supramolecular hydrogel of bionanoparticles and hyaluronan

We report here the synthesis of a light- and chemical-responsive supramolecular hydrogel of bacteriophage M13 and hyaluronan locked by the molecular recognition between β-cyclodextrin and trans-azobenzene moieties. Compared to rod-like tobacco mosaic virus (TMV), the filamentous bacteriophage M13 with higher aspect ratio and more flexible structure formed a much more robust hydrogel with hyaluronan, which was confirmed by the inversion test and rheological measurement. The resulting M13 hydrogel showed sol–gel transition behaviours induced by either photo-irradiation or competitive host or guest molecules. Moreover, cells could be facilely encapsulated and delivered using this supramolecular hydrogel with great cell viability.

Transient viscoelasticity study of tobacco mosaic virus/Ba2+ superlattice

Recently, we reported a new method to synthesize the rod-like tobacco mosaic virus (TMV) superlattice. To explore its potentials in nanolattice templating and tissue scaffolding, this work focused the viscoelasticity of the superlattice with a novel transient method via atomic force microscopy (AFM). For measuring viscoelasticity, in contrast to previous methods that assessed the oscillating response, the method proposed in this work enabled us to determine the transient response (creep or relaxation) of micro/nanobiomaterials. The mathematical model and numerical process were elaborated to extract the viscoelastic properties from the indentation data. The adhesion between the AFM tip and the sample was included in the indentation model. Through the functional equation method, the elastic solution for the indentation model was extended to the viscoelastic solution so that the time dependent force vs. displacement relation could be attained. To simplify the solving of the differential equation, a standard solid model was modified to obtain the elastic and viscoelastic components of the sample. The viscoelastic responses with different mechanical stimuli and the dynamic properties were also investigated.

Self-Assembly of Rodlike Virus to Superlattices

Rodlike tobacco mosaic virus (TMV) has been found to assemble into superlattices in aqueous solution using the polymer methylcellulose to induce depletion and free volume entropy-based attractive forces. Both transmission electron microscopy and small-angle X-ray scattering show that the superlattices form in both semidilute and concentrated regimes of polymer, where the free volume entropy and the depletion interaction are the dominant driving force, respectively. The superlattices are NaCl and temperature responsive. The rigidity of the rodlike nanoparticles also plays an important role for the formation of superlattices through the free volume entropy mechanism. Compared to the rigid TMV particle, flexible bacteriophage M13 particles are only responsive to the depletion force and thus only assemble in highly concentrated polymer solution, where depletion interaction is dominant.

β-structure of the coat protein subunits in spherical particles generated by tobacco mosaic virus thermal denaturation

Conversion of the rod-like tobacco mosaic virus (TMV) virions into “ball-like particles” by thermal denaturation at 90–98 °C had been described by R.G. Hart in 1956. We have reported recently that spherical particles (SPs) generated by thermal denaturation of TMV at 94–98 °C were highly stable, RNA-free, and water-insoluble. The SPs were uniform in shape but varied widely in size (53–800 nm), which depended on the virus concentration. Here, we describe some structural characteristics of SPs using circular dichroism, fluorescence spectroscopy, and Raman spectroscopy. It was found that the structure of SPs protein differs strongly from that of the native TMV and is characterized by coat protein subunits transition from mainly (about 50%) α-helical structure to a structure with low content of α-helices and a significant fraction of β-sheets. The SPs demonstrate strong reaction with thioflavin T suggesting the formation of amyloid-like structures.

Biomolecular Assembly of Thermoresponsive Superlattices of the Tobacco Mosaic Virus with Large Tunable Interparticle Distances

Not too friendly with their neighbors: In the presence of certain polymers, such as methyl cellulose (MC), the rodlike tobacco mosaic virus (TMV) formed a superlattice in which the distance between the virus particles could be controlled within a wide range up to approximately 5 times their diameter. The spacing between the TMV particles in the superlattice showed a unique dependence on temperature and on the concentration of TMV (see picture).

A Kinetic Zipper Model and the Assembly of Tobacco Mosaic Virus

We put forward a modified Zipper model inspired by the statics and dynamics of the spontaneous reconstitution of rodlike tobacco mosaic virus particles in solutions containing the coat protein and the single-stranded RNA of the virus. An important ingredient of our model is an allosteric switch associated with the binding of the first protein unit to the origin-of-assembly domain of the viral RNA. The subsequent addition and conformational switching of coat proteins to the growing capsid we believe is catalyzed by the presence of the helical arrangement of bound proteins to the RNA. The model explains why the formation of complete viruses is favored over incomplete ones, even though the process is quasi-one-dimensional in character. We numerically solve the relevant kinetic equations and show that time evolution is different for the assembly and disassembly of the virus, the former exhibiting a time lag even if all forward rate constants are equal. We find the late-stage assembly kinetics in the presence of excess protein to be governed by a single-exponential relaxation, which agrees with available experimental data on TMV reconstruction.

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.

Self-assembly of anisotropic tobacco mosaic virus nanoparticles on gold substrate

A facile approach to assembled virus film with tunable structure is presented. Rod-like tobacco mosaic virus (TMV) was selected as the prototype in this study for its anisotropic structural feature. TMV can either “lie down” or “stand up” on gold substrate by tuning the solution pH. A quartz crystal microbalance with dissipation monitoring was used to monitor the pH-dependent self-assembly behavior of TMV nanoparticles, and atomic force microscopy and single molecule force spectroscopy further confirmed the different assembly structures.

Tobacco mosaic virus templated synthesis of one dimensional inorganic–polymer hybrid fibres

Inorganic–polymer hybrid nanofibres were prepared by using a rod-like tobacco mosaic virus (TMV) as a template. With tetraethylorthosilicate (TEOS) as a precursor, long silica-coated TMV fibres were formed via a head-to-tail assembly, which showed a substantial increase of the elastic modulus. Furthermore, homogenous titania–TMV hybrid fibres could be prepared using polyaniline-coated TMV fibres as a template, which were used to form a composite film that was able to sense liquefied petroleum gases.

Biological Templated Synthesis of Water-Soluble Conductive Polymeric Nanowires

One-dimensional (1D) conductive nanowire is one of the most important components for the development of nanosized electronic devices, sensors, and energy storage units. Great progresses have been made to prepare the 1D-conducting polymeric nanofibers by the low concentration process or the synthesis with hard or soft templates. However, it still remains as a great challenge to prepare polymeric nanofibers with narrow dispersity, high aspect ratio, and good processibility. With the rod-like tobacco mosaic virus as the template, 1D-conducting polyaniline and polypyrrole nanowires can be readily prepared via a hierarchical assembly process. This synthesis discloses a unique way to produce composite fibrillar materials with controlled morphology and great processibility, which can promote many potential applications including electronics, optics, sensing, and biomedical engineering.