Monitoring SARS-COV-2 surrogate TGEV individual virions structure survival under harsh physicochemical environments

Effective airborne transmission of coronaviruses via liquid microdroplets requires a virion structure that must withstand harsh environmental conditions. Due to the demanding biosafety requirements for the study of human respiratory viruses, it is important to develop surrogate models to facilitate their investigation. Here we explore the mechanical properties and nanostructure of transmissible gastroenteritis virus (TGEV) virions in liquid milieu and their response to different chemical agents commonly used as biocides. Our data provide two-fold results on virus stability: First, while particles with larger size and lower packing fraction kept their morphology intact after successive mechanical aggressions, smaller viruses with higher packing fraction showed conspicuous evidence of structural damage and content release. Second, monitoring the structure of single TGEV particles in the presence of detergent and alcohol in real time revealed the stages of gradual degradation of the virus structure in situ. These data suggest that detergent is three orders of magnitude more efficient than alcohol in destabilizing TGEV virus particles, paving the way for optimizing hygienic protocols for viruses with similar structure, such as SARS-CoV-

Surface characterization of alkane viral anchoring films prepared by titanate-assisted organosilanization

Studies of virus adsorption on surfaces with optimized properties have attracted a lot of interest, mainly due to the influence of the surface in the retention, orientation and stability of the viral capsids. Besides, viruses in whole or in parts can be used as cages or vectors in different areas, such as biomedicine and materials science. A key requirement for virus nanocage application is their physical properties, i.e. their mechanical response and the distribution of surface charge, which determine virus-substrate interactions and stability. In the present work we show two examples of viruses exhibiting strong surface interactions on homogeneous hydrophobic surfaces. The surfaces were prepared by titanate assisted organosilanization, a sol-gel spin coating process, followed by a mild annealing step. We show by surface and interface spectroscopies that the process allows trapping triethoxy-octylsilane (OCTS) molecules, exhibiting a hydrophobic alkane rich surface finishing. Furthermore, the surfaces remain flat and behave as more efficient sorptive surfaces for virus particles than mica or graphite (HOPG). Also, we determine by atomic force microscopy (AFM) the mechanical properties of two types of viruses (human adenovirus and reovirus) and compare the results obtained on the OCTS functionalized surfaces with those obtained on mica and HOPG. Finally, the TIPT+OCTS surfaces were validated as platforms for the morphological and mechanical characterization of virus particles by using adenovirus as initial model and using HOPG and mica as standard control surfaces. Then, the same characteristics were determined on reovirus using TIPT+OCTS and HOPG, as an original contribution to the catalogue of physical properties of viral particlesThis work was supported by the grant Ayudas a Proyectos de I+D para Jovenes Doctores de la Universidad Autonoma de Madrid 2021 (SI3/PJI/2021–00216) supported by Comunidad de Madrid and Universidad Autonoma de Madrid to M.H-P. Also, M.H-P acknowledges funding from the Spanish Ministry of Science and Innovation (TED2021–129937B-I00). Grant PID2019–104098GB-I00/AEI/ 10.13039/501100011033, co-funded by the Spanish State Research Agency and the European Regional Development Fund to C.S.M. The CNB-CSIC was further supported by a Spanish State Research Agency Severo Ochoa Excellence grant (SEV 2017–0712). C.S.M is a member of the CSIC funded consortium LifeHub (CSIC grant number: 202120E47). REACT-EU funding by Comunidad Autonoma de Madrid is also acknowledged. M.M.S acknowledges funding from MCIN/AEI /10.13039/501100011033 (PID2020–112770RB-C22). P.J.P acknowledges projects FIS2017–89549-R; and FIS2017–90701-REDT. P.J.P also acknowledges the Human Frontiers Science Program (HFSPO RGP0012/2018

Chaperonins: Nanocarriers with biotechnological applications

Chaperonins are molecular chaperones found in all kingdoms of life, and as such they assist in the folding of other proteins. Structurally, chaperonins are cylinders composed of two back-to-back rings, each of which is an oligomer of ~60-kDa proteins. Chaperonins are found in two main conformations, one in which the cavity is open and ready to recognise and trap unfolded client proteins, and a “closed” form in which folding takes place. The conspicuous properties of this structure (a cylinder containing a cavity that allows confinement) and the potential to control its closure and aperture have inspired a number of nanotechnological applications that will be described in this review