Fluorescence signatures of SARS-CoV-2 spike S1 proteins and a human ACE-2: excitation-emission maps and fluorescence lifetimes

Abstract

Significance: Fast and reliable detection of infectious SARS-CoV-2 virus loads is an important issue. Fluorescence spectroscopy is a sensitive tool to do so in clean environments. This presumes a comprehensive knowledge of fluorescence data.Aim: We aim at providing fully featured information on wavelength and time-dependent data of the fluorescence of the SARS-CoV-2 spike protein S1 subunit, its receptor-binding domain (RBD), and the human angiotensin-converting enzyme 2, especially with respect to possible optical detection schemes.Approach: Spectrally resolved excitation-emission maps of the involved proteins and measurements of fluorescence lifetimes were recorded for excitations from 220 to 295 nm. The fluorescence decay times were extracted by using a biexponential kinetic approach. The binding process in the SARS-CoV-2 RBD was likewise examined for spectroscopic changes.Results: Distinct spectral features for each protein are pointed out in relevant spectra extracted from the excitation-emission maps. We also identify minor spectroscopic changes under the binding process. The decay times in the biexponential model are found to be ð2.0 AE 0.1Þ ns and ð8.6 AE 1.4Þ ns.Conclusions: Specific material data serve as an important background information for the design of optical detection and testing methods for SARS-CoV-2 loaded media.

Cerebral microvascular complications associated with SARS-CoV-2 infection: How did it occur and how should it be treated?

“…The spike (S) protein of SARS-CoV-2 consists of S1 and S2 subunits. The S1 subunit has a primary role in adherence of the viral to the host cells [74] , [75] . In this case, the receptor-binding domain (RBD) is a class-I membrane-fusion protein located at the S1 subunit and is accountable for the fusion of the ACE-2 receptor with viral membranes [76] .…”

The SARS‐CoV‐2 specific IgG antibodies biophotonic sensor

“… Elaborating the fiber optic biosensors which properly work with the telecommunication wavelength (1550 nm). This is an unusual wavelength for a biophotonic sensor because fiber optic biosensors are dedicated to working in lower wavelengths [ 23 , 42 , 43 ] Elaboration of the effective method of antibodies proteins detection based on the signal transmitted back by standard telecommunication single‐mode fiber [ 44 , 45 ]. Fast detection of the protein of SARS‐CoV‐2 by the use of the optical method in a drop of sample—with our sensor the detection in 5 μl sample is possible within <1 min [ 43 , 46 ].…”

“…Elaborating the fiber optic biosensors which properly work with the telecommunication wavelength (1550 nm). This is an unusual wavelength for a biophotonic sensor because fiber optic biosensors are dedicated to working in lower wavelengths [ 23 , 42 , 43 ]…”