Development of urinary albumin immunosensor based on colloidal AuNP and PVA

The development of immunosensors with high sensitivity and specificity in detecting the pathogenic or physiologically relevant molecules in the body, offers a powerful opportunity in early diagnosis and treatment of diseases. In this study, we developed a new competitive immunosensor with employing antibody (Ab) labeled AuNP (Ab-AuNP) and PVA modified screen-printed carbon electrode (SPCE) surface to detect the urine albumin. Field emission scanning electron microscopy (FE-SEM) of modified electrode showed a suitable and stable attachment between HSA antigen- mAb and AuNP. Cyclic voltammetric (CV) method demonstrated that modification process was well performed. Electrochemical measurements including differential pulse voltammetry (DPV) and square wave voltammetry (SWV) were employed for quantitative antigen detection. The electrochemical measurements performed with other proteins mixed with samples demonstrated a high specificity and selectivity for this biosensor in detecting the HSA. In optimal conditions, the immunosensor could detect HSA in a high linear range (from 2.5 to 200 μg/mL) with a low detection limit of 25 ng/mL. This new strategy could be improved and applied to detect the other antigen.