Biosensors based on electrogenerated chemiluminescence transducers, combining advantages offered by the selectivity of the biological recognition elements and the sensitivity of ECL technique, are powerful tool for ultrasensitive biomolecule detection and quantification.Nanomaterials including nanoparticles and nanotubes, prepared from metals, semiconductor, carbon or polymeric species, are of considerable interest in the biosensor field owing to their unique physical and chemical properties, which has led to novel biosensors that have exhibited high sensitivity and stability [13-15]. Particularly, nanomaterials have been investigated for their ability to enhance the efficiencies of ECL biosensors.The aim of the present review is to give the readers a critical overview of nanomaterials applications in ECL biosensors.

For the sake of clarity, this review will specifically focus on the application of nanomaterials in ECL biosensors in view of different functions of nanomaterials on the enhancing ECL signal based on taking as modification electrode materials, carrier of ECL labels and ECL-emitting species. Particular attention will be given to publications that appeared from 2004 to 2008. The remarkable sensitivity of ECL biosensors is achieved by coupling nanomaterial-based amplification units and various amplification processes. The use of nanomaterials carriers for designing multi-target ECL protocols will be documented in detail. Readers are referred to several excellent references [1, 5-10] and relevant websites [16, 17] for further and deeper discussions on certain specific topics.

2.?Nanomaterials as modification electrode materialsThe most important step for building a biosensor is to immobilize the biomolecule on the transducer. A successful platform should have special properties for immobilizing or integrating biomolecule stably at a transducer surface and efficiently maintain the functionality GSK-3 of the biomolecule, while providing accessibility to the target analyte and an intimate contact with the transducer surface. The development of a stable and good biocompatible matrix for immobilization of bimolecules is very crucial to improve the analytical performance of a biosensor. More and more attention has been paid to ECL biosensors functionalized with nanomaterials due to an enormous surface area-to-volume ratio of nanomaterials, and highly susceptibility of ECL to surrounding environments. The diversity in compositions (inorganic or organic, metals or semiconductors), shapes (particles, rods, wires, tubes, etc.), and the readiness for surface functionalization (physical, chemical, or biological) has enabled the fabrication of various functional nanostructures for ECL biosensor.