Electrochemical immunosensing chip using selective surface modification, capillary-driven microfluidic control, and signal amplification by redox cycling

A sensitive electrochemical immunosensing chip is presented by employing (i) selective modification of protein-resistant surfaces; (ii) fabrication of a stable Ag/AgCl reference electrode; (iii) capillary-driven microfluidic control; (iv) signal amplification by redox cycling along with enzymatic reaction. Purely capillary-driven microfluidic control is combined with electrochemical sandwich-type immunosensing procedure. Selective modification of the surfaces is achieved by chemical reactivity-controlled patterning and electrochemical deposition. Fluidic control of the immunosensing chip is achieved by spontaneous capillary-driven flows and passive washing. The detection limit for mouse IgG in the immunosensing chip is 10 pg/mL.