The conjunction of (bio-)chemical recognition elements with nanoscale biological building blocks such as virus particles is considered as a very promising strategy for the creation of biohybrids opening novel opportunities for label-free biosensing. This work presents a new approach for the development of biosensors using tobacco mosaic virus (TMV) nanotubes or coat proteins (CPs) as enzyme nanocarriers. Sensor chips combining an array of Pt electrodes loaded with glucose oxidase (GOD)-modified TMV nanotubes or CP aggregates were used for amperometric detection of glucose as a model system for the first time. The presence of TMV nanotubes or CPs on the sensor surface allows binding of a high amount of precisely positioned enzymes without substantial loss of their activity, and may also ensure accessibility of their active centers for analyte molecules. Specific and efficient immobilization of streptavidin-conjugated GOD ([SA]-GOD) complexes on biotinylated TMV nanotubes or CPs was achieved via bioaffinity binding. These layouts were tested in parallel with glucose sensors with adsorptively immobilized [SA]-GOD, as well as [SA]-GOD crosslinked with glutardialdehyde, and came out to exhibit superior sensor performance. The achieved results underline a great potential of an integration of virus/biomolecule hybrids with electronic transducers for future applications in biosensorics and biochips. (C) 2016 Elsevier B.V. All rights reserved.

Due to its small dimensions and high stability, tobacco mosaic virus (TMV) is used as nano-scaffold frequently. Its surface can be engineered to meet specific needs for technical, medical or materials applications. However, not all technically desirable TMV coat protein (CP) mutants can be propagated in plants successfully, if they change the efficiency of virion assembly. In order to circumvent this problem, a novel wild type (wt) CP-assisted and RNA-directed assembly procedure was designed for a recalcitrant CP mutant: Although pure hexahistidine-tagged CP cannot form particles on its own with TMV RNA in vitro, it was integrated into full-length particles if blended with wt CP in different proportions. The resulting rods formed dense monolayers with short range alignment on silicon substrates, substantially different from the largely wavy patterns obtained with wt TMV. Since they also mediated efficient ZnO deposition under mild conditions, the approach has yielded a new class of biotemplates which are amenable to the formation of nanostructured hybrid materials with adjustable texture for various applications.