Chip-based immunomagnetic separation of human chorionic gonadotropin

Ahi, Elçin Ezgi
Gümüştaş, Aysen
Çiftçi, Hakan
Çağlayan, M Gökhan
Selbes, Yeşim Somay
Çoğun, Ferah
Yıldırım, Ender
Tamer, Uğur
Human chorionic gonadotropin (hCG) is a glycoprotein, and it can be misused by male athletes. This glycoprotein affects testosterone production and release in the human body. Therefore, the use of this hormone as a performance enhancing drug has been prohibited by the World Anti-Doping Agency [1]. In this study, a microchip, which had developed by our group, was used for the detection of hCG using both colorimetric and spectrofluorometric measurements. For this purpose, gold coated magnetic nanoparticles (MNPs) and gold nanorods (AuNRs) were synthesized and modified using different reagents and specific antibody, respectively [2]. Then they were used to form in-chip sandwich immunoassay with the hCG for colorimetric measurement. The developed microchips consist of four micro-chambers connected to each other by microchannels. The first chamber was filled with modified MNPs, the second and third chambers were filled with modified AuNRs and washing buffer, respectively. The last chamber was filled with 3, 3´, 5, 5´-tetramethylbenzidine (TMB) and H2O2, then used for monitoring the color change. The chip process was performed by moving the MNPs from the first chamber through the microchannels using a magnet. The first step of the process is forming sandwich structure between the MNPs and the horse radish peroxidase (HRP) -labelled AuNRs. The second step includes washing the sandwich structure with the washing buffer. Finally, the enzymatic reaction between the TMB and H2O2 occurs in the presence of HRP in the last chamber, then the color change is observed. To get fluorescence signal, this time the second chamber of the microchip was filled with the europium (Eu) labelled-anti hCG, the third and last chamber was filled with the washing buffer. Finally, measurement was performed in the last chamber following same procedure used in colorimetric detection by a spectrofluorometer equipped with a fiber optic prob.
Citation Formats
E. E. Ahi et al., “Chip-based immunomagnetic separation of human chorionic gonadotropin,” Çanakkale, Turkey, 2016, p. 361, Accessed: 00, 2021. [Online]. Available: