A universal microarray platform: Towards high-throughput electrochemical detection

• A microarray with 8 × 5 pairs of ITO and 8 Pt-Ag/AgCl coaxial electrodes was built.
• Each cell with 2 ITO discs could be constructed by patterning PDMS upon ITO glass.
• Pt-Ag/AgCl coaxial electrode with compact structure was removeable and durable.
• Detecting units on the chip were mutually independent and owned well uniformity.
• Two tumor markers were detected simultaneously with high-throughput manner.

Here a novel electrochemical microarray platform towards high-throughput detection is presented. This microarray owns 8 × 5 well-organized oval cells and 8 × 5 pairs of ITO discs (two ITO discs for each pair in one cell). 8 mobile and aligned Pt–Ag/AgCl coaxial electrodes with compact configuration, where Pt column is used for counter electrode and Ag/AgCl for reference electrode, are inserted in 8 cells separately and made up 8 groups of three-electrode detection system together with 8 pairs of ITO discs. To demonstrate the applicability of such design, two kinds of bioconjugates, carboxyl graphene nanosheets–methylene blue (CGS–MB) and carboxyl graphene nanosheets–Prussian blue (CGS–PB) nanocomposites selected as model redox indicators and crosslinked with two kinds of antibodies were coated on the pair of ITO discs to realize a high-throughput detection of two tumor markers based on the increasing spatial blocking and impedance from the formed immunocomplex.