Paper-based microfluidic devices for electrochemical immunofiltration analysis of human chorionic gonadotropin

An electrochemical immunofiltration analysis was introduced into microfluidic paper-based analytical devices (mu PADs) for the first time, which was based on photolithography and screen-printing technology. The hydrophilic test zones of the aldehyde-functionalized screen-printed electrodes (SPEs) were biofunctionalized with capture antibodies (Ab(1)). A sensitive immune detection method was developed by using primary signal antibody functionalized gold nanoparticles (GNPs/Ab(2)) and alkaline phosphatase conjugated secondary antibody (ALP-IgG). Differential pulse voltammetry (DPV) was performed to detect the electrochemical response. The microfluidic paper-based electrochemical immunosensor (mu-PEI) was optimized and characterized for the detection of human chorionic gonadotropin (HCG), a model analyte, in a linear range from 1.0 mIU mL(-1) to 100.0 IU mL(-1) with a detection limit of 0.36 mIU mL(-1). Additionally, the proposed mu-PEI was used to test HCG in real human serum and obtained satisfactory results. The disposable, efficient, sensitive and low-cost mu-PEI has exhibited great potential for the development of point-of-care testing (POCT) devices that can be applicated in healthcare monitoring.