A team of researchers have developed an easy-to-use colorimetric assay for the detection of food contaminated with salmonella. The assay is based on a novel nucleic acid probe that is cleaved by an RNase enzyme specific to the salmonella species. As the team report in the journal Angewandte ... more
Tracking the Happiness Hormone
Electrochemical serotonin microsensors for stable long-term measurement in real time
Dysregulation of serotonin plays a role in many psychiatric disorders, including severe depression and anxiety. In the journal Angewandte Chemie, a research team has now introduced an implantable, electrochemical microsensor that makes it possible to study serotonin dynamics in the brain in real time. In contrast to previous sensors, these are not deactivated by deposition of serotonin oxidation products because the measurement occurs without current flow.
Serotonin, also known as the “happiness hormone”, is one of our most important neurotransmitters, regulating many processes in our brain, especially our feelings, but also appetite, memory, and sleep. A better understanding of these processes on a molecular level could improve the diagnosis and treatment of mental illnesses. Previous electrochemical methods worked with a microelectrode, on which serotonin is directly oxidized and the resulting current is measured. However, the resulting oxidation products polymerize, adhere to the electrode surface (fouling), and rapidly deactivate the sensor (about 90 % signal loss within 30 minutes).
A team led by Ying Jiang and Lanqun Mao at Beijing Normal University and the Chinese Academy of Sciences (Beijing, China) has now developed a serotonin sensor that provides extremely stable signals, even during long-term experiments, because almost no fouling due to serotonin oligomers occurs. The method is based on galvanic redox potentiometry (GRP), which is a zero-current technique.
The core of the sensor is a tiny bipolar electrode, which can simplistically be described as a rod with one end protruding into the liquid being measured while the other is in an electrolyte solution with electrochemical properties that are precisely adjusted to the analyte molecule. An electrical contact is established exclusively through the electrolyte solution. At one end of the electrode, an electrochemical equilibrium is established between electrolyte ions in various charge states (in this case: IrCl62−/IrCl63−), at the other end, there is an equilibrium between serotonin and its oxidized form. By using a device to measure the voltage, it is possible to measure the spontaneously established potential difference relative to a reference electrode. This difference is dependent on the serotonin concentration. Because only the voltage is measured and no current flows, there is almost no deposition of oligomeric serotonin products. Quantitative measurements are possible over a broad range of concentrations and over a long period of time.
Sensors implanted into the brains of guinea pigs were able to follow the release of serotonin after stimulation with potassium ions in real time. The team made one interesting observation after administering Escitalopram, a serotonin reuptake inhibitor often prescribed to treat severe depression and anxiety disorders. Its activity seems to depend more strongly on slowing the uptake process than on modulation of the extracellular serotonin concentration. This insight could be important for the treatment of psychiatric disorders.
- psychiatric disorders
- real-time analysis
Hydrogen peroxide as a target in the fight against cancer?
Reactive oxygen species (ROS) are reputed for their involvement in carcinogenesis. Results from a study published in the journal Angewandte Chemie have now shown that the level of one such ROS, hydrogen peroxide, is significantly higher in pancreatic cancer cells, unlike the level of other ... more
The quantitative detection of specific antibodies in complex samples such as blood can inform on many different diseases but usually requires a complicated laboratory procedure. A new method for the rapid, inexpensive, yet quantitative and specific point-of-care detection of antibodies has ... more
- 1Electronic noses sniff out volatile organic compounds
- 2X-ray imaging captures fleeting defects in sodium-ion batteries
- 3Verder Group acquires specialist for particle characterization
- 4Verder Group acquires ERWEKA
- 5Launching Revvity: A Scientific Solutions Company Powering Innovation from Discovery to Cure
- 6The World’s Smallest Impedance Spectroscopy System in the Form of a Pill Finds Weak Spots in Machines and People
- 7Why are neuron axons long and spindly?
- 8Ultra-long protein fibrils give clues on dementia risk
- 9AI supports analysis of metallic materials
- 10Bioindicator for the occurrence of PFAS
- Shrimp from Finding Nemo could help keep your white bread white
- Biological specimens imaged with X-rays without damage
- For shorter approval times: New process simulates decomposition of too long ...
- Presence of nicotine and antidepressants detected in Antarctic waters
- Electronic noses sniff out volatile organic compounds
- Fluorescent blue coumarins in a folk-medicine plant could help us see inside cells
- Single-atom vibrational spectroscopy now sensitive at level of chemical bonds
- In search of the 'holy grail': researchers observe lithium ions in real time
- Tracking the Happiness Hormone
- Eppendorf: New production site in Shanghai metropolitan region