Amperometric glutamate biosensor based on self-assembling glutamate dehydrogenase and dendrimer-encapsulated platinum nanoparticles onto carbon nanotubes.

A novel amperometric biosensor based on self-assembling glutamate dehydrogenase (GLDH) and poly(amidoamine) dendrimer-encapsulated platinum nanoparticles (Pt-PAMAM) onto multiwall carbon nanotubes (CNTs) has been developed for the determination of glutamate. The formation of the self-assembled (GLDH/Pt-PAMAM)(n)/CNTs construction was investigated by zeta-potential and high resolution transmission electron microscopy (HRTEM). The results indicated the uniform growth of the layer-by-layer nanostructures onto carboxyl-functionalized CNTs. The electrocatalytic property of the (GLDH/Pt-PAMAM)(n)/CNTs modified electrode to glutamate in presence of NAD(+) (beta-nicotinamide adenine dinucleotide, 0.1mM) was investigated at a low overpotential 0.2V by electrochemical measurements. The results showed it had series of attractive characteristics, such as a large determination range (0.2-250muM), a short response time (within 3s), a high sensitivity (433muA/mM(-1)cm(2)) and good stability (85% remains after 4 weeks).