Monitoring viral SARS-CoV-2 spike glycans using silicon carbide nanotubes as optical biosensors: a quantum simulation

In this paper, the sensitivity of nanotube-based nano sensors composed of silicon carbide to viral environments have been investigated. For this purpose, we designed various SiCNTs and calculated the electronic properties of each. The effects of N-linked and O-linked viral spike glycan adsorption on z-SiCNTs and a-SiCNTs were investigated. The results of electronic density of states and optoelectronic properties showed that the most obvious changes in the optical bandgap among all zigzag configurations were related to the case SiCNT(8,0)–N-linked complex. However, the largest changes in the optical bandgap was observed for the SiCNT(10,10)–O-linked complex. Also, time-dependent density functional theory (TD-DFT) was used to study the absorption spectrum. NPA and NBO analyses revealed configuration-dependent charge transfer and donor–acceptor interactions. The alterations in the UV-Vis spectrum of SiCNTs have been studied, when they are in the SARS-COV-2 virus spike environments. As a result, it was found that SiCNTs and spike virus glycoproteins have optical absorption in the visible, and UV region, respectively. The observed color change results from adsorption-induced electronic modulation of the z-SiCNT–glycan complexes and the consequent alteration of their optical absorption. In the z-SiCNTs, in addition to the variation in the optical absorption intensity, a significant blue shift has also occurred. In contrast, for the a-SiCNTs, the changes in wavelength were not particularly remarkable. Finally, the results confirmed that z-SiCNT(8,0) and a-SiCNT(10,10) are promising candidates for optical sensing of N- and O-linked SARS-CoV-2 spike glycans.