title: Analytical detection of biological thiols in a microchip capillary channel.
abstract: Sulfur-containing amino acids, such as cysteine and homocysteine play crucial roles in biological systems for the diagnosis of medical states. In this regard, this paper deals with separation, aliquot and detection of amino thiols on a microchip capillary electrophoresis with electrochemical detection in an inverted double Y-shaped microchannel. Unlike the conventional capillary electrophoresis, the modified microchannel design helps in storing the separated thiols in different reservoirs for further analysis, if required; and also eliminates the need of electrodes regeneration. The device was fabricated using conventional photolithographic technique which consisted of gold microelectrodes on a soda lime glass wafer and microchannels in PDMS mold. Multiple detections were performed using in-house fabricated dual potentiostat. Based on amperometric detection, cysteine and homocysteine were analyzed in 105 s and 120 s, respectively after diverting in branched channels. Repeated experiments proved the good reproducibility of the device. The device produced a linear response for both cysteine and homocysteine in electrochemical analysis. To prove the practicality of device, we also analyzed cysteine and homocysteine in real blood samples without any pre-treatment. Upon calculation, the device showed a very low limit of detection of 0.05 μM. The modified microchip design shall find a broad range of analytical applications involving assays of thiols and other biological compounds.
authors.affiliation: Department of Nanoscience & Engineering, Myongji University, 38-2 Nam-dong, Yongin, Gyeonggi 449-728, Republic of Korea.
authors.forename: Rohit
authors.initials: R
authors.lastname: Chand
authors.forename: Sandeep Kumar
authors.initials: SK
authors.lastname: Jha
authors.forename: Kamrul
authors.initials: K
authors.lastname: Islam
authors.forename: Dawoon
authors.initials: D
authors.lastname: Han
authors.forename: Ik-Soo
authors.initials: IS
authors.lastname: Shin
authors.forename: Yong-Sang
authors.initials: YS
authors.lastname: Kim
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D002197:Capillary Action; D003217:Conductometry / Q000295:instrumentation*; D019075:Electrophoresis, Capillary / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D056656:Lab-On-A-Chip Devices; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013438:Sulfhydryl Compounds / Q000032:analysis*
chemical_list: D013438:Sulfhydryl Compounds