One-step immobilization of antibodies for α-1-fetoprotein immunosensor based on dialdehyde cellulose/ionic liquid composite

A novel immunosensor for α-1-fetoprotein based on dialdehyde cellulose/ionic liquid composite film as a matrix has been developed. Microcrystalline cellulose was activated by sodium metaperiodate to produce dialdehyde cellulose. Antibodies can be immobilized on the electrode by a one-step method through covalent bonding of the aldehyde groups of dialdehyde cellulose with the amino groups of antibodies, in which no additional chemical cross-linking step is required. Moreover, ionic liquid added can improve the conductivity of the sensing interface and, therefore, can enhance the electrochemical signal. In this work, α-1-fetoprotein was detected within the range from 0.1 to 60 ng ml−1 with a detection limit of 0.07 ng ml−1 (signal/noise = 3). The proposed immunosensor had good specificity and reproducibility. It was used to determine real samples with satisfactory results.