Synthesis of Fluorescein Aldehydes for the Sensitive Detection of L-Cysteine

Abstract

Amino acids containing thiol-groups such as Cysteine (Cys), Homocysteine (Hcy), and Glutathione play an important role in a great variety of biological processes. However, too low, but also too high concentrations can have negative effects on human health. Therefore, it is of great importance to sensitively detect these risk factors for cardiovascular and neuronal diseases. Furthermore, Cys is an essential amino acid for the growth of pathogenic water-borne bacteria, like Legionella sp. Hence, a reliable, sensitive and selective Cys-detection method that is incorporated into automated biosensors would represent a great tool for a broad range of biological and medical applications. We describe the simple synthesis of fluorescein aldehyde probes for the detection of biologically important thiols, focusing on Cys. The probes displayed highly sensitive responses to L-Cysteine hydrochloride monohydrate in the range of their physiologically relevant levels in the visible and UV spectral region.

Keywords

• fluorescein aldehydes
• L-Cysteine
• detection