Detection of Biothiols Using Some Novel Chemosensors: An Overview

Thiol-containing amino acids and peptides play crucial roles in many physiological processes. For example, Cysteine (Cys) and Homocysteine (Hcy) are considered to be related to a number of health disorders, such as renal failure, AIDS, Alzheimer's and Parkinson's diseases, atherosclerotic cardiovascular diseases, neural tube defects, and coronary heart disease. Glutathione (GSH), an important tripeptide with a thiol group, performs vital biological functions that are involved in combating oxidative stress and maintaining redox homeostasis. Cysteine also plays important roles in our bodies as an antioxidant, a metal cofactor binder in enzymes, and a protein structure stabilizer by disulfide bond formation in the proteins. Hcy is involved in cellular growth and GSH in redox homeostasis. Hence, the rapid, sensitive, and selective detection of such biothiols is of considerable importance and significant interest. Different fluorescent chemosensors have been introduced to develop and improve the detection techniques and accuracy of these biothiols. In this review article, we have presented some research works to show a guiding principle for the design of effective chemosensors that are highly sensitive and selective for the detection of a particular group of biothiols in an aqueous medium. In line with these developments, the researchers have developed novel chemosensors that signal the binding events of these above-mentioned biothiols through their optical properties. The binding mechanism and properties have also been established with different theoretical studies. Their applications in the form of colorimetric kits, logic gates, live-cell imaging, and quantification from different biological samples have also been developed.