The preparation of reagentless electrochemical immunosensor based on a nano-gold and chitosan hybrid film for human chorionic gonadotrophin.

A novel amperometric immunosensor for determination of human serum chorionic gonadotrophin (hCG) was constructed by immobilizing hCG antibody with nano-gold and chitosan (CHIT) hybrid film electrochemical co-deposited on a glassy carbon electrode. The fabricated procedures and electrochemical behaviors of proteins on such an interface were characterized with electrochemical impedance, cyclic voltammetry and chronoamperometry. The effect of incubation time on the electrochemical behavior of immunosensor was studied and other experimental conditions such as mass ratio of CHIT and HAuCl4, depositing time of hybrid film, the pH, and temperature were studied too. The current response of the immunosensor is in linear relationship with concentration of hCG. The resulting immunosensor offers an excellent amperometric response for hCG ranging from 0.20 to 100 mIU mL(-1) with a detection limit of 0.1 mIU mL(-1). A satisfactory determination of hCG in serum samples can be obtained by this immunosensor.