Hematite (α-Fe2O3) nanoparticles were synthesized by the solid transformation of ferrous hydroxide and ferrihydrite in hydrothermal condition. The as-prepared α-Fe2O3 nanoparticles were characterized by UV-vis, PL, XRD, Raman, TEM, AFM, FESEM, and EDX analysis. The experimental results indicated the formation of uniform hematite nanoparticles with an average size of 45 nm and perfect crystallinity. The electrochemical behavior of a GC/α-Fe2O3 electrode was studied using CV and EIS techniques with an electrochemical probe, [Fe(CN)6](3-/4-) redox couple. The electrocatalytic activity was investigated toward DA oxidation in a phosphate buffer solution (pH 6.8) by varying different experimental parameters. The chronoamperometric study showed a linear response in the range of 0-2 μM with LoD of 1.6 μM for DA. Square wave voltammetry showed a linear response in the range of 0-35 μM with LoD of 236 nM for DA.
Benzeneboronate of catecholic carboxyl methyl esters, N-acetyldopamine, coumarin and catechol estrogens were prepared as crystalline derivatives in high yield. Related catechol compounds with extra polar functional group(s) (OH, NH2) do not form or only partially form unstable cyclic boronate derivatives.
For a healthy life, the human biological system should work in order. Scheduled lifestyle and lack of nutrients usually lead to fluctuations in the biological entities levels such as neurotransmitters (NTs), proteins, and hormones, which in turns put the human health in risk. Dopamine (DA) is an extremely important catecholamine NT distributed in the central nervous system. Its level in the body controls the function of human metabolism, central nervous, renal, hormonal, and cardiovascular systems. It is closely related to the major domains of human cognition, feeling, and human desires, as well as learning. Several neurological disorders such as schizophrenia and Parkinson's disease are related to the extreme abnormalities in DA levels. Therefore, the development of an accurate, effective, and highly sensitive method for rapid determination of DA concentrations is desired. Up to now, different methods have been reported for DA detection such as electrochemical strategies, high-performance liquid chromatography, colorimetry, and capillary electrophoresis mass spectrometry. However, most of them have some limitations. Surface plasmon resonance (SPR) spectroscopy was widely used in biosensing. However, its use to detect NTs is still growing and has fascinated impressive attention of the scientific community. The focus in this concise review paper will be on the principle of SPR sensors and its operation mechanism, the factors that affect the sensor performance. The efficiency of SPR biosensors to detect several clinically related analytes will be mentioned. DA functions in the human body will be explained. Additionally, this review will cover the incorporation of nanomaterials into SPR biosensors and its potential for DA sensing with mention to its advantages and disadvantages.
5-HT(1A) serotonin and D1 dopamine receptor agonists have been postulated to be able to improve negative and cognitive impairment symptoms of schizophrenia, while partial agonists and antagonists of the D2 and 5-HT(2A) receptors have been reported to be effective in reducing positive symptoms. There is therefore a need for well-defined homology models for the design of more selective antipsychotic agents, since no three-dimensional (3D) crystal structures of these receptors are currently available. In this study, homology models were built based on the high-resolution crystal structure of the β(2)-adrenergic receptor (2RH1) and further refined via molecular dynamics simulations in a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid bilayer system with the GROMOS96 53A6 united atom force field. Docking evaluations with representative agonists and antagonists using AutoDock 4.2 revealed binding modes in agreement with experimentally determined site-directed mutagenesis data and significant correlations between the computed and experimental pK (i) values. The models are also able to distinguish between antipsychotic agents with different selectivities and binding affinities for the four receptors, as well as to differentiate active compounds from decoys. Hence, these human 5-HT(1A), 5-HT(2A), D1 and D2 receptor homology models are capable of predicting the activities of novel ligands, and can be used as 3D templates for antipsychotic drug design and discovery.