Microchip Capillary Electrophoresis Based Separation and Detection of Cysteine and Homocysteine

Abstract

Cysteine and homocysteine are the biological thiols which have an important function in various biochemical processes in our body. Alterations in their level lead to various abnormalities. Therefore, we fabricated a miniaturized platform for capillary electrophoresis that could separate and detect these amino thiols electrochemically. The device was fabricated using conventional photolithography technique on the glass substrate. The microchannel was molded in polydimethylsiloxane with gold electrodes deposited on glass for separation and detection. Based on the amperometric detection, we could detect cysteine in 93 sec while homocysteine was detected in 111 sec.

Competitive Inhibition of the Enzyme-Mimic Activity of Gd-Based Nanorods toward Highly Specific Colorimetric Sensing of l-Cysteine

“…Cysteine, a sulfur containing amino acid, plays a vital role in protein synthesis, metabolism, detoxification, and biological signaling. − Deficiencies in cysteine are known to result in growth defects, skin lesions, lethargy, fat loss, and liver damage, while elevated levels are associated with cardiovascular and neurotoxic diseases. − Given the high biological significance of this important amino acid, accurate quantification of cysteine concentrations is of paramount importance. Current strategies including spectroscopy, ,, capillary electrophoresis, and high-performance liquid chromatography − have shown potential for cysteine sensing. However, the need for technical expertise, complexity of operations, high cost of instrumentation, long detection times, and laborious sample preparation limits the practical applicability of such techniques. , In contrast, colorimetric sensors based on nanozymes address these limitations and offer significant potential in the development of sensors against a range of chemical and biological molecules. ,,,,− …”

“…29−31 Given the high biological significance of this important amino acid, accurate quantification of cysteine concentrations is of paramount importance. Current strategies including spectroscopy, 30,32,33 capillary electrophoresis, 34 and high-performance liquid chromatography 35−37 have shown potential for cysteine sensing. However, the need for technical expertise, complexity of operations, high cost of instrumentation, long detection times, and laborious sample preparation limits the practical applicability of such techniques.…”

Determination of Homocysteine in Urine and Saliva by Microchip Electrophoresis

“…The analysis time on the glass microchip using amperometric detection was less than 80 s [6]. A polydimethylsiloxane (PDMS) microchip produced by a simple photolithographic technique facilitated the rapid separation of HCy and cysteine [20]. MCE analyses are more favorable than CE because they are considerably shorter, achieve higher degrees of separation efficiency and, in particular, reduce overall costs associated with chemical consumption and waste production.…”

Colorimetric Sensing of Cysteine in serum by the competitive adsorption toward AuNPs between Cysteine and ATP

“…Thus, it is very important to develop some simple analytical detection methods for monitoring total plasma cysteine levels [1] . The majority of the reported methods for analysis of cysteine are electrochemical methods based on its redox chemistry, fluorescent probe technology based on the strong nucleophilicity of a thiol group, or capillary electrophoresis with mass spectrometric and so forth [2][3][4] . These methods have their own drawbacks and advantages.…”