Molecularly imprinted photo-electrochemical sensor for hemoglobin detection based on titanium dioxide nanotube arrays...

A novel molecularly imprinted photo-electrochemical sensor based on CdS/TiO₂ nanocomposites was constructed for precisely detection of hemoglobin under visible light irradiation. CdS quantum dots were decorated on the surface of TiO₂ nanorod arrays to form a heterojunction, which could enhance the charge-transfer efficiency for visible light and further increase the photo-generated current of the sensor. The molecularly imprinted polymer film assembled by dopamine monomer had achieved excellent performance for specifically binding with human hemoglobin. The hemoglobin bound on the sensor could catalyze the oxidation reaction of 4-chloro-1-naphthol by H₂O₂, generating insoluble product on the sensor surface and triggering an obviously decrease on photocurrent. The molecularly imprinted photo-electrochemical sensor exhibited excellent sensitivity, selectivity and stability for the detection of human hemoglobin. The sensor had a linear range from 0.01 to 100 ng mL^-1 with a detection limit of 0.53 pg/mL (S/N = 3). Furthermore, the sensor was successfully applied on the analysis of human hemoglobin in the urine samples.