International Journal of Nanomedicine (Oct 2021)
Recent Advances in Electrochemical and Optical Sensors for Detecting Tryptophan and Melatonin
Abstract
Zeeshan Ahmad Khan,1– 3 Paul Jung-Soo Hong,4,* Christina Hayoung Lee,5,* Yonggeun Hong1– 3,6,7 1Department of Physical Therapy, College of Healthcare Medical Science & Engineering, Inje University, Gimhae, Gyeong-nam, 50834, Korea; 2Biohealth Products Research Center (BPRC), Inje University, Gimhae, Gyeong-nam, 50834, Korea; 3Ubiquitous Healthcare & Anti-Aging Research Center (u-HARC), Inje University, Gimhae, Gyeong-nam, 50834, Korea; 4Department of Chemistry, Newton South High School, Newton, MA, 02459, USA; 5Department of Biology, College of Arts and Sciences, Vanderbilt University, Nashville, TN, 37212, USA; 6Department of Rehabilitation Science, Graduate School of Inje University, Gimhae, Gyeong-nam, 50834, Korea; 7Department of Medicine, Division of Hematology/Oncology, Harvard Medical School-Beth Israel Deaconess Medical Center, Boston, MA, 02215, USA*These authors contributed equally to this workCorrespondence: Yonggeun HongDepartment of Rehabilitation Science, Graduate School of Inje University, 197 Inje-ro, Gimhae, Gyeong-nam, 50834, KoreaTel +82-55-320-3681Fax +82-55-329-1678Email [email protected]: Tryptophan and melatonin are pleiotropic molecules, each capable of influencing several cellular, biochemical, and physiological responses. Therefore, sensitive detection of tryptophan and melatonin in pharmaceutical and human samples is crucial for human well-being. Mass spectrometry, high-performance liquid chromatography, and capillary electrophoresis are common methods for both tryptophan and melatonin analysis; however, these methods require copious amounts of time, money, and manpower. Novel electrochemical and optical detection tools have been subjects of intensive research due to their ability to offer a better signal-to-noise ratio, high specificity, ultra-sensitivity, and wide dynamic range. Recently, researchers have designed sensitive and selective electrochemical and optical platforms by using new surface modifications, microfabrication techniques, and the decoration of diverse nanomaterials with unique properties for the detection of tryptophan and melatonin. However, there is a scarcity of review articles addressing the recent developments in the electrochemical and optical detection of tryptophan and melatonin. Here, we provide a critical and objective review of high-sensitivity tryptophan and melatonin sensors that have been developed over the past six years (2015 onwards). We review the principles, performance, and limitations of these sensors. We also address critical aspects of sensitivity and selectivity, limit and range of detection, fabrication process and time, durability, and biocompatibility. Finally, we discuss challenges related to tryptophan and melatonin detection and present future outlooks.Keywords: tryptophan, melatonin, electrochemical, sensors, voltammetry, optical
