Ruthenium-Anchored Carbon Sphere-Customized Sensor for the Selective Amperometric Detection of Melatonin

Abstract

Melatonin (MT), a pineal gland hormone, regulates the sleep/wake cycle and is a potential biomarker for neurodegenerative disorders, depression, hypertension, and several cancers, including prostate cancer and hepatocarcinoma. The amperometric detection of MT was achieved using a sensor customized with ruthenium-incorporated carbon spheres (Ru–CS), possessing C- and O-rich catalytically active Ru surfaces. The non-covalent interactions and ion–molecule adducts between Ru and CS favor the formation of heterojunctions at the sensor–analyte interface, thus accelerating the reactions towards MT. The Ru–CS/Screen-printed carbon electrode (SPCE) sensor demonstrated the outstanding electrocatalytic oxidation of MT owing to its high surface area and heterogeneous rate constants and afforded a lower detection limit (0.27 μM), high sensitivity (0.85 μA μM −1 cm−2), and excellent selectivity for MT with the co-existence of crucial neurotransmitters, including norepinephrine, epinephrine, dopamine, and serotonin. High concentrations of active biomolecules, such as ascorbic acid and tyrosine, did not interfere with MT detection. The practical feasibility of the sensor for MT detection in pharmaceutical samples was demonstrated, comparable to the data provided on the product labels. The developed amperometric sensor is highly suitable for the quality control of medicines because of its low cost, simplicity, small sample size, speed of analysis, and potential for automation.

Utilizing a Disposable Sensor with Polyaniline-Doped Multi-Walled Carbon Nanotubes to Enable Dopamine Detection in Ex Vivo Mouse Brain Tissue Homogenates

“…The following chemicals were received from Sigma–Aldrich (Seoul, Republic of Korea): ammonia aqueous solution (25–28%), aniline (99%), ammonium peroxydisulphate (APS) (Extrapure, 99%), hydrochloric acid (HCl, 37%), concentrated sulfuric acid (H 2 SO 4 , 98%), ethanol (99.5% purity), chloroform, MWCNTs (>95 wt%), potassium ferri and ferrocyanides [Fe(CN) 6 ] 3−/4− , potassium chloride (KCl), dopamine hydrochloride (DA), glucose, glutamate (Glu), norepinephrine (NE), serotonin (5–HT), ascorbic acid (AA), and uric acid (UA). Phosphate buffers (0.1 M) were prepared following a standard protocol reported elsewhere [ 23 ], and all solutions were prepared utilizing 18.2 MΩ cm water. Only aniline was distilled before use; all other chemicals were utilized exactly as they were supplied (analytical grade).…”

Association between urinary metals and prostate-specific antigen in aging population with depression: a cross-sectional study

“…After ingestion through food, water, and air, the human body metabolizes and eliminates heavy metals in various ways, primarily through urine. The concentration of heavy metals in urine provides an indication of the body’s metal levels after metabolism ( 14 , 15 ). The International Association for Research on Cancer (IARC) has classified beryllium and beryllium-containing compounds as Group 1 carcinogens.…”

Conducting Polymers in Amperometric Sensors: A State of the Art over the Last 15 Years with a Focus on Polypyrrole-, Polythiophene-, and Poly(3,4-ethylenedioxythiophene)-Based Materials

“…According to the response mechanism, electrochemical sensors can be classified into potentiometric, amperometric, and impedimetric sensors. Some recent advances in each of these classes can be found in references [25][26][27][28][29][30][31][32][33][34][35][36][37]. Although impedimetric sensors are often more sensitive than amperometric ones, these are commonly preferred due to the easier performance of the amperometry measure, as well as current data collection and interpretation [38].…”