Tobacco mosaic virus disks, preparation of samples to investigate mineralization by low voltage electron microscopyPart of:
Tobacco mosaic virus (TMV) has been used as a template for synthesis of nanostructured hybrid functional materials since many years. Through bio-inspired mineralization, a wide range of metal and semiconducting materials e.g SiO2, ZnO, ZnS have been deposited.1, 2. Different TMV coat protein (CP) mutants and a variety of conditions have been applied to study the influence of the biotemplate on the mineralization process. However, studies on the mechanism for deposition of inorganic phases on the biotemplate are scarce. Very recently, we have developed a facile approach for selective deposition of TMV with ZnS, and using conventional optical characterization methods a heterogeneous nucleation was proposed.3 Further, the mineralization of TMV with ZnO nanoparticles with controllable size can be used to extend our explorations in this issue. Since the inner TMV channel is 4 nm in diameter, synthesis of ZnO, which forms bigger crystals already within the mineralization solution, will help to draw conclusions for the deposition mechanism. A possible heterogeneous nucleation in this case could be proven by presence of mineralized material also in the inner virus channel independent of the pre-formed nanoparticles. A possibility to have access to both the outer surface of TMV but also to the inner channel is the use of small artificially produced virus-like particles (VLP) stabilized by a scaffold RNA buried within the protein coat. One of these VLPs are the disks68 (containing 68 CP) with a height of 10 nm. The challenge for investigation by low voltage electron microscopy is to get these disks68 in a pure form without residual free CP or additives like buffer salts. Therefore, we established a purification protocol including size exclusion chromatography which resulted in CP-free disk preparations with a yield of >25%. These disks can now be immobilized horizontally on a surface and be used to investigate the mineralization process.
1. K. Altintoprak, A. Seidenstucker, A. Welle, S. Eiben, P. Atanasova, N. Stitz, A. Plettl, J. Bill, H. Gliemann, H. Jeske, D. Rothenstein, F. Geiger and C. Wege, Beilstein J Nanotech, 2015, 6, 1399-1412.
2. P. Atanasova, N. Stitz, S. Sanctis, J. H. M. Maurer, R. C. Hoffmann, S. Eiben, H. Jeske, J. J. Schneider and J. Bill, Langmuir, 2015, 31, 3897-3903.
3. P. Atanasova, I. Kim, B. Chen, S. Eiben and J. Bill, Advanced Biosystems, 2017, DOI: 10.1002/adbi.201700106, 1700106-n/a.