Integrated microfluidic paper-based system for determination of whole blood albumin

A method is proposed for determining the concentration of albumin (ALB) in human whole blood samples using a 3-dimensional (3D) microfluidic paper-based chip and a smart detection module. In fabricating the paper based chip, the reaction area is implanted with bromocresol green (BCG) reagent and the device is stored in a nitrogen (N-2) environment at a temperature of -15 degrees C until needed for use. In the detection process, 10 I of whole blood is dropped onto the entrance area of the chip and the plasma within the sample diffuses through a separation channel into the reaction zone. A reaction is induced between the ALB in the plasma and the BCG reagent in the reaction area by heating the chip at 37 degrees C for 6 min. The ALB concentration is then detected using a colorimetry technique implemented on a cell phone in the form of a self-written app. It is shown that the detection results obtained for 40 pure ALB samples and 30 whole blood samples are consistent with those obtained using a traditional spectrophotometry method (R-2 = 0.9837 and R-2 = 0.9968). The proposed detection system thus provides a reliable tool for practical ALB determination purposes.