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.

Aligned Electroactive TMV Nanofibers as Enabling Scaffold for Neural Tissue Engineering.

Electroactive nanofibers were fabricated by in situ polymerization of aniline on the surface of tobacco mosaic virus (TMV) using sodium poly(styrenesulfonate) (PSS) as dopant. These electroactive TMV/PANi/PSS nanofibers were employed to support growth of neuronal cells, resulting in augmentation of the length of neurites. In addition, the percentage of cells with neurites was increased in comparison to cells cultured on TMV-derived nonconductive nanofibers. The TMV-based electroactive nanofibers could be aligned in capillaries that could guide the outgrowth direction of neurites, increase the percentage of cells with neurites, and lead to a bipolar cellular morphology. Our results demonstrate that the electroactivity and topographical cues provided by TMV/PANi/PSS nanofibers can synergistically stimulate neural cells differentiation and neurites outgrowth, which make it a promising scaffolding material for neural tissue engineering.

Genetically Engineered Plant Viral Nanoparticles Direct Neural Cells Differentiation and Orientation.

An important aim of tissue engineering is to design biomimetic materials with specific cell binding motifs and precisely controlled structural organization, thereby providing biochemical and physical cues for desired cellular behaviors. Previously, our group generated genetically modified tobacco mosaic virus (TMV) displaying integrin binding motifs, RGD1, RGD7, PSHRN3, P15, and DGEA. The resulting rod-like virus particles displaying integrin binding motifs were biocompatible with Neuro 2A (N2a), a mouse neural crest-derived cell line, and could promote the neurite outgrowth of N2a. The genetically modified viruses could be assembled with aligned orientation in the capillary by applying a shear force. The resulting aligned substrates were able to dictate directional neurite outgrowth of N2a cells. Therefore, this method could be potentially applied for neural tissue engineering, as a neural conduit for repairing peripheral nerve injuries.

Virus-templated FRET platform for the rational design of ratiometric fluorescent nanosensors.

We report here the construction of a bacteriophage M13-templated supramolecular nanosystem, i.e. M13-ß-CD/Ada-FITC/Ada-RhB, which can be used as effective ratiometric fluorescent sensors for intracellular sensing.