Multianalyte sensing

Electrode surfaces modified with a multilayered surface architecture prepared by a layer-by-layer repeated deposition of several enzyme mono-layers show a modulated increase of surface-bound protein with a subsequent increase in output current, which is directly correlated with the number of deposited protein layers. The versatility of this approach allows alternate layers of different proteins for the manufacture of electrode surfaces, which are the basis for multianalyte sensing devices with multiple substrate specificities. The surface chemistry used for the manufacture of multilayered electrode surfaces is similar to that previously described for the preparation of affinity sensors, and is based on the stabilization of self-assembled multilayer assemblies by specific affinity interactions, electrostatic attraction, or covalent binding between adjacent monolayers. 

Multianalyte sensing is important for clinical, biological, environmental, and industrial analysis in which simultaneous detection of more than one analyte is required. For example, measurement of pH, O2, CO2, antibodies, DNA sequences, antibiotics, viruses, and bacteria in single blood samples can provide physicians with rapid and comprehensive information about a patient s medical condition. 

Although still in the research stage, it is expected that distributed sensing capabilities will improve many fiberoptic chemical sensor technologies. In particular, integration of distributed and multianalyte sensing will result in powerful fiber-optic chemical sensor devices. 

Henares, T. G. Takaishi, M. Yoshida, N. Terabe, S. Mizutani, F. Sekizawa, R. Hisamoto, H. Integration of multianalyte sensing functions on a capillary-assembled microchip simultaneous determination of ion concentrations and enzymatic activities by a Drop-and-Sip technique. Anal. Chem. 2007, 79, 908-915. 

On the other hand, nowadays, the general demands required for analytical systems are extended to multianalyte sensing. Thus, tremendous efforts are focusing on the development of multianalyte assays with the advantages of short analysis time, simplified analytical procedure, decreased sampling volume, improved test efficiency, and reduced cost as compared to parallel single-analyte assays. In this context modified sensors could be promising analytical tools. 

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