Activation of Cellulose Membranes with 1,1′-Carbonyldiimidazole or 1-Cyano-4-dimethylaminopyridinium tetrafluoroborate as a Basis for the Development of Immunosensors

Methods for the activation of a cellulose dialysis membrane for immunosensor applications have been developed. For activation two reagents, 1,1′-carbonyldiimidazole (CDI) and 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP), were compared with respect to the coupling efficiency for glucose oxidase (GOx) and 1,8-diamino-2,6-dioxaoctane. The maximum level of activation was 2.4 μmol cm−2 for CDI and 0.2 μmol cm−2 for CDAP activation. We observed 1.5 μg cm−2 and 0.4 × 10−4 U cm−2 GOx with CDI-activated membranes whereas 1.7 μg cm−2 and 7.2 × 10−4 U cm−2 GOx were observed with CDAP-activated membranes. With 1,8-diamino-2,6-dioxaoctane amino group densities of 0.165 and 0.09 μmol cm−2 were observed via CDI and CDAP activation, respectively. An amino-modified membrane was used for coupling a ligand (pentapeptide) and an immunoenzymometric assay for hemoglobin A1c was carried out.