Electrochemical Amyloid-Based Biosensor for the Determination of Metal Ions

Abstract

The interplay between metal ions and amyloids plays a significant role not only in the pathogenesis of neurodegenerative disorders such as Alzheimer's and Parkinson's disease but also in the development of application technologies for the synthesis of metal nanomaterials. In this study, we investigate the interplay between amyloids and heavy metal ions using screen-printed electrochemical sensor functionalized with amyloid fibrils. For this purpose, amyloid fibril-functionalized screen-printed electrochemical sensor was devised. Various heavy metal ions (e.g., palladium, mercury, copper, and cadmium) directly reacted with amyloid fibrils at different concentrations. In addition, molecular dynamics simulation was used to compare the individual binding energies between metal ions and amyloids, which was consistent with the results of the electrochemical analysis. We believe that amyloid functionalized electrochemical sensor is helpful to gain insight into the interaction between amyloids and heavy metal ions as well as the development of amyloid-metal ion application techniques.

Nafion-Radical Hybrid Films on Carbon Nanotube Transistors for Monitoring Antipsychotic Drug Effects on Stimulated Dopamine Release

“…Conventional methods like high-performance liquid chromatography (HPLC), luminescent methods, and electrochemical techniques have been utilized to quantify dopamine release in living systems and evaluate the efficacy of antipsychotic drugs. [4][5][6][7][8][9][10][11][12][13] However, these techniques have their own limitations. For example, HPLC can be complex and costly.…”

“…Moreover, the detection limit of common electrochemical techniques was only at a micromolar level. [9][10][11][12][13][14] On the other hand, field-effect transistor (FET) devices have shown distinct advantages, and they have been extensively used to detect dopamine 4 in various environments. [15][16][17][18] However, they were not utilized to evaluate the efficacy of actual antipsychotic drugs as well as real-time cellular measurements.…”

“…It was previously reported that negatively charged nafion layers could attract positively charged molecules, and, thus, nafion has been used as a catalytic layer to attract dopamine near a sensor surface. [12][13][14] In our work, a nafion film not only acts as a catalytic layer but also as a matrix holding ABTS • radicals to enhance the sensitivity of our sensor. The redox reactions between dopamine and ABTS • radicals generate hydrogen ions (H + ) which can diffuse in the nafion film, increase the density of positive charges near the transducer of CNT-FET sensors, and eventually change the electrical currents in the sensor.…”

“…It also should be mentioned that nafion has been extensively utilized as a part of sensors operating in aqueous solutions with different chemical substances including dopamine and PBS buffer, implying that the nafion was stable after our dopamine sensing experiments in PBS buffer. [12][13][14] For the measurements of dopamine release from living cells, PC12 cells were cultured in a culture dish as reported previously (Figure 1-iii). 24 Then, a PC12 cell suspension was introduced on an NRC sensor using a pipette (Figure 1-iv), and the cells were stimulated by high-concentrated K + solutions for the release of dopamine (Figure 1-v).…”

Removal of radioactive cesium from contaminated water by whey protein amyloids–carbon hybrid filters

“…32,41 As shown in previous studies, the strongest binding motif of the b-lactoglobulin protein sequence is the 121-cys residue containing the amyloidogenic fragment LACQCL. 30,42,43 Radiographic imaging of the amyloid-carbon hybrid lter (Fig. 3) shows the spatial distribution of 137 Cs as captured in the membrane.…”