An electrochemical albumin-sensing system utilizing microfluidic technology**Preliminary results of the current paper were presented at the 2nd International Meeting on Microsensors and Microsystems 2006 (National Cheng Kung University, Tainan, Taiwan, 15–18 January).

Abstract

This paper reports an integrated microfluidic chip capable of detecting the concentration of albumin in urine by using an electrochemical method in an automatic format. The integrated microfluidic chip was fabricated by using microelectromechanical system techniques. The albumin detection was conducted by using the electrochemical sensing method, in which the albumin in urine was detected by measuring the difference of peak currents between a bare reference electrode and an albumin-adsorption electrode. To perform the detection of the albumin in an automatic format, pneumatic microvalves and micropumps were integrated onto the microfluidic chip. The albumin sample and interference mixture solutions such as homovanillic acid, dopamine, norepinephrine and epinephrine were first stored in one of the three reservoirs. Then the solution comprising the albumin sample and interference solutions was transported to pass through the detection zone utilizing the pneumatic micropump. Experimental data showed that the developed system can successfully detect the concentration of the albumin in the existence of interference materials. When compared with the traditional albumin-sensing method, smaller amounts of samples were required to perform faster detection by using the integrated microfluidic chip. Additionally, the microfluidic chip integrated with pneumatic micropumps and microvalves facilitates the transportation of the samples in an automatic mode with lesser human intervention. The development of the integrated microfluidic albumin-sensing system may be promising for biomedical applications.