Electroanalytical sensor based on nanocrystalline diamond electrodes and microelectrode arrays

摘要

A diamond electrode and a diamond microelectrode array for biosensors and electroanalytical applications, such as electrochemical impedance spectroscopy (EIS), are disclosed. The electrode comprises a layer of ultra-smooth conductive nanocrystalline diamond (NCD) having a resistivity of >0.05 Ωcm and a surface roughness of <20 nm Ra. Preferably, the diamond layer comprises boron or nitrogen-doped ultrananocrystalline diamond (UNCD) having an average grain size <10 nm and a surface roughness <10 nm Ra. It may be patterned to define a microelectrode array with a plurality of individually addressable electrodes, each having a diameter in the range from 100 nm to 100 μm. The surface of each microelectrode is hydrogen-terminated before bio-functionalization, i.e. modifying with sensing molecules for detection of a specific biological or chemical target and coating with a blocker for reducing non-specific binding. These diamond electrodes exhibited substantial increases in sensitivity, selectivity and signal reproducibility, e.g. for detection of E. coli K12 using EIS.

主权项

1. An electroanalytical sensor comprising at least one electrode, each electrode comprising:
a layer of conductive nanocrystalline diamond (NCD) having a resistivity of >0.05 Ωcm and a surface having a surface roughness of <20 nm Ra (arithmetic mean value), wherein the layer of conductive nanocrystalline diamond comprises ultrananocrystalline diamond (UNCD) having an average grain size of <10 nm.