Fabrication of a 3D interdigitated double-coil microelectrode chip by MEMS technique

We have fabricated an interdigitated double-coil microelectrode chip for the determination of traces of phosphate by making use of a MEMS technique and enzyme immobilization technology. The chip is composed of two 3-dimensional strip microelectrodes which form a double coil microelectrode configuration with steep sidewalls and high aspect ratio. This novel configuration results in a high current response during amplification by redox cycling. The enzyme pyruvate oxidase was immobilized on the chip using gold nanoparticles as a support. Phosphate can be determined by using this chip with good sensitivity and linearity and in concentrations ranging from 0.5 μM to 7 μM.