Detection of cancer through simultaneous detection of serotonin and dopamine

Significance 

Serotonin (5-hydroxytryptamine; 5-HT) is a hormone and a neurotransmitter and it is involved in cognitive activities, central nervous function and mood regulation. The effect of serotonin extends to the immune system, vasculature and the gut. Thus, an abnormal regulation of serotonin secretion can result in pathologies in these areas. Serotonin is also important in the development of the mammary gland and abnormalities in the regulation of serotonin production plays an important role in the development of breast cancer. There is a change in the expression of serotonin receptors observed in breast cancer cells. This contributes to the abnormal cell growth and allows the tumor avoid the tumor suppressive actions of serotonin. It is therefore important to monitor the concentration of serotonin for the early diagnosis and prognosis of breast cancer. In addition, the uptake of dopamine by its transporter is affected by a high level of serotonin making it necessary to develop a dopamine sensor.

Several methods have been developed to detect serotonin and these include enzyme-linked immunosorbent assay (ELISA), HPLC and spectroscopy. Despite their benefits, these methods can only be performed by well-trained professionals and require multistep procedures, pretreatment steps, large amount of sample and expensive instrumentation. These serve as setbacks, which make these methods non-applicable as point-of care test (POCT) methods. However, a much more promising method is the electrochemical detection of serotonin because it is simple, affordable, non-invasive, and has the potential of being used with POC devices. Therefore, it is necessary to develop highly precise and sensitive sensor that can monitor the amount of serotonin released from biological samples such as cancer cells. To this note, scientists at Pusan National University in South Korea: Dr Saeromi Chung, Dr. Mahmood H. Akhtar, A. Benboudiaf, Professor Deog‐Su Park and Professor Yoon‐Bo Shim, developed a new sensor for serotonin and dopamine using [email protected]/pTBA Pd (C2H4N2S2)2 electrode. They demonstrated the clinical utility of their sensor and that it can be used to monitor serotonin levels in both normal and cancer cells. Their study is published in the Journal Electroanalysis.

The research team fabricated an electrochemical sensor to detect both serotonin and dopamine in human plasma samples and breast cancer cells, based on the conducting polymer composite with a palladium complex (Pd (C2H4N2S2)2). The sensor was developed by using the Pd(C2H4N2S2)2 complex-anchored poly2,2:5,2-terthiophene-3-(p-benzoic acid) (pTBA) layer on the AuNPs decorated reduced graphene oxide ([email protected]) substrate. They observed that the dynamic ranges was from 0.1 to 200 μM, for dopamine and from 0.02 to 200 μM for serotonin and the detection limits were 24.0 nM and 2.5 nM (RSD <4.20, 3.78%), respectively.

The authors successfully confirmed that the amount of serotonin released from breast cancer cells is 3.1 times higher than the normal cells. Serotonin concentration was found to be 135.2 nM in normal cells and 411.7 nM in cancer cells. The recovery ratios were in the range from 95.2-104.0% for dopamine and from 97.2-103.8% for serotonin. The recovery tests proved that the sensor was accurate and could be used in clinical settings.

In summary, the Pusan National University researchers have developed an innovative sensor that is simple, precise and can detect simultaneously dopamine and serotonin in biological samples. This will be useful in the management of breast cancer.

About the author

Yoon-Bo Shim is currently a Distinguished Professor at the Department of Chemistry and Institute of BioPhysio Sensor Technology (IBST), Pusan National University, Republic of Korea. Earlier he completed his PhD from the same university and went to University of New Mexico, USA for the Postdoctoral training and as a visiting scholar for three years. At the beginning of his professional career, he was the visiting professor at Yokohama National University and Kyoto University, Japan, University of Pittsburgh, USA. In 2002, he was appointed as a director of research center, IBST to conduct sophisticated research to develop electrochemical chemical sensor/biosensor and he is still involved in the institute. Moreover, he is the Editors of Electroanalysis (Wiely-VCH, German).

Professor Yoon-Bo’s research is focused on the fabrication of low cost and efficient electrochemical biosensor platform. As a prominent researcher in this field, he extensively explored conducting polymer especially terthiophene and its derivatives for signal transduction, attaching biorecognition elements to the sensor surface and nanobioconjugate formation. Over the years, he established some important fundamental electrochemical phenomena of protein, DNA and conducting polymer. Recently his lab pioneered a very simple and rapid electrochemical microfluidic separation device where AC voltage is applied for separation. This system is superior to most conventional chromatographic methods. In his diverse research career, he published 354 papers on high impact journal (h-index 56) and citied over 10500 times.

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Email: [email protected]

Reference

Chung, S., Akhtar, M. H., Benboudiaf, A., Park, D. S., & Shim, Y. B. A Sensor for Serotonin and Dopamine Detection in Cancer Cells Line Based on the Conducting Polymer− Pd Complex Composite. Electroanalysis, 2020 Mar: 32(3), 520-527. doi.org/10.1002/elan.201900568.

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