Localized surface plasmon resonance aptasensor for selective detection of SARS-CoV-2 S1 protein.

In this work, we designed and developed a method to detect S1 spike protein of SARS-CoV-2. The portable Localized Surface Plasmon Resonance instrument equipped with a two-channel system was combined with the biotin-streptavidin platform on a nanogold surface to immobilize biotinylated aptamers. The proposed assay does not utilize antibodies or enzyme-based reagents, further simplifying the detection method.

Dual roles of tau R peptides on Cu(II)/(I)-mediated reactive oxygen species formation.

Metal dyshomeostasis plays a critical role in the reactive oxygen species (ROS) formation and protein misfolding and aggregation; hence, contributing to neurodegeneration. Tau protein plays a key role in normal cellular function by maintaining microtubule formation in brain. The role of metal ions on tau protein biochemistry has not been systematically evaluated, but earlier reports indicated that metal ions modulate the complex biochemistry of this protein and its peptides.

Aggregation of gelsolin wild-type and G167K/R, N184K, and D187N/Y mutant peptides and inhibition.

Gelsolin, an actin-binding protein, is localized intra- and extracellularly in the bloodstream and throughout the body. Gelsolin amyloidosis is a disease characterized by several point mutations that lead to cleavage and fibrillization of gelsolin. The D187 mutation to N or Y leads to aggregation of peptide fragments with shortest aggregating peptide identified as 182SFNNGDCFILD192.

Structural evaluations of tau protein conformation: methodologies and approaches.

Protein-misfolding diseases are based on a common principle of aggregation initiated by intra- and inter-molecular contacts. The structural and conformational changes induced by biochemical transformations such as post-translational modifications (PTMs), often lead to protein unfolding and misfolding. Thus, these order-to-disorder or disorder-to-order transitions may regulate cellular function.

Selective Electrochemical versus Chemical Oxidation of Bulky Phenol.

The electrochemical oxidation of selected tert-butylated phenols 2,6-di-tert-butyl-4-methylphenol (1), 2,6-di-tert-butylphenol (2), 2,4,6-tri-tert-butylphenol (3), 2-tert-butylphenol (4), and 4-tert-butylphenol (5) was studied in an aprotic environment using cyclic voltammetry, square-wave voltammetry, and UV-vis spectroscopy. All compounds exhibited irreversible oxidation of the corresponding phenol or phenolate ion. Compound 2 was selectively electrochemically oxidized, while other phenol analogues underwent mostly chemical oxidation.

Evaluation of ferritin and transferrin binding to tau protein.

Tau protein is a neurodegeneration biomarker. Due to the high concentration of metal ions in the brain, the metallation of tau proteins and their catalytic role in reactive oxygen formation have been identified as a major biochemical pathway of neurodegeneration. High levels of iron ions have been detected in Alzheimer's disease brains.

Electrochemical detection of anti-tau antibodies binding to tau protein and inhibition of GSK-3β-catalyzed phosphorylation.

Tau protein hyperphosphorylation triggers tau aggregation and its toxicity, leading to neuronal death and cell-to-cell toxicity. Hence, inhibition of protein kinases is a viable tool toward reduction of tau toxicity. By targeting various epitopes of Tau441 protein immobilized on Au surface, the protein kinase inhibition by anti-tau antibodies was measured by surface electrochemistry.

Electrochemical Characterization of Protein Adsorption onto YNGRT-Au and VLGXE-Au Surfaces.

The adsorption of the proteins CD13, mucin and bovine serum albumin on VLGXE-Au and YNGRT-Au interfaces was monitored by electrochemical impedance spectroscopy in the presence of [Fe(CN)6](3-/4-). The hydrophobicity of the Au surface was tailored using specific peptides, blocking agents and diluents. The combination of blocking agents (ethanolamine or n-butylamine) and diluents (hexanethiol or 2-mercaptoethanol) was used to prepare various peptide-modified Au surfaces.