A label-free graphene-based impedimetric biosensor for real-time tracing of the cytokine storm in blood serum; suitable for screening COVID-19 patients.

Concurrent with the pandemic announcement of SARS-CoV-2 infection by the WHO, a variety of reports were published confirming the cytokine storm as the most mortal effect of the virus on the infected patients. Hence, cytokine storm as an evidenced consequence in most of the COVID-19 patients could offer a promising opportunity to use blood as a disease progression marker. Here, we have developed a rapid electrochemical impedance spectroscopy (EIS) sensor for quantifying the overall immune activity of the patients. Since during the cytokine storm many types of cytokines are elevated in the blood, there is no need for specific detection of a single type of cytokine and the collective behavior is just measured without any electrode functionalization. The sensor includes a monolayer graphene on a copper substrate as the working electrode (WE) which is able to distinguish between the early and severe stage of the infected patients. The charge transfer resistance (R CT) in the moderate and severe cases varies about 65% and 138% compared to the normal groups, respectively and a specificity of 77% and sensitivity of 100% based on ELISA results were achieved. The outcomes demonstrate a significant correlation between the total mass of the three main hypercytokinemia associated cytokines including IL-6, TNF-α and IFN-γ in patients and the R CT values. As an extra application, the biosensor's capability for diagnosis of COVID-19 patients was tested and a sensitivity of 92% and specificity of 50% were obtained compared to the RT-PCR results.

Spectroscopic, molecular docking and molecular dynamic simulation studies on the complexes of ß-lactoglobulin, safranal and oleuropein.

Herbal bioactive compounds have captured pronounced attention considering their health-promoting effects as well as their functional properties. In this study, the binding mechanism between milk protein bovine ß-lactoglobulin (ß-LG), oleuropein (OLE) and safranal (SAF) found in olive leaf extract and saffron, respectively via spectroscopic and in silico studies. Fluorescence quenching information exhibited that interactions with both ligands were spontaneous and hydrophobic interactions were dominant. Also, the CD spectroscopy results demonstrated the increase in ß-sheet structure and decrease in the α-helix content for both ligands. Size of ß-LG-OLE complex was higher than ß-LG-SAF due to the conformation and larger molecular size. Molecular docking and simulation studies revealed that SAF and OLE bind in the central calyx of ß-LG and the surface of ß-LG next to hydrophobic residues. Lastly, OLE formed a more stabilized complex compared to SAF based on the molecular dynamic simulation results.

Carbon nanotube based dielectric spectroscopy of tumor secretion; electrochemical lipidomics for cancer diagnosis.

Cell free diagnosis of cancer is one of the crucial fields in new generation of medical technology. In this regard, cancer detection based on coastal fluids secreted from the tissues (named as secretome) has attracted a lot of attention. Lipids are important macromolecules could be found with much higher concentrations in secretome of cancer tissues vs. normal ones. On the other hand, lipids are the main dielectric components of the secretome with respect to proteins and ions. Here for the first time we introduced an electrochemical lipidomics based on electrical impedance spectroscopy (EIS) of the secretomes to detect the cancerous samples due to the lipidic content of their secretions. The EIS sensor was fabricated by multiwall carbon nanotube (MWCNT) arrays as conductive and super hydrophobic materials to have great interactive surface with the lipidic content of the solution. Results of the tests on the secretions of more than 100 human biopsied breast tissues showed the promising match between the charge transfer resistance (RCT) of samples' secretions and pathological states of the tissues with meaningful boundary (up to 8 kΩ for normal and more than 13 kΩ for cancer samples). Mass spectroscopic analyses confirmed the higher content of lipids in cancer secretomes. Electrical lipidomics of the secretome shed new lights in cell free cancer diagnosis and could be applied as a complementary clinical approach in all of biopsy based diagnoses in future.