Nature Commun. 4, 2001 (2013)

Credit: © 2013 NPG

Multiple disease markers in clinical samples can currently be detected with arrays of electrochemical silicon-based biosensors. However, the degree of readouts that can be made in parallel is limited by the complexity of integrated active electronics, as the electrical contacts of each sensor have to be addressed independently. Brian Lam and colleagues have now designed and fabricated solution-based circuits that can increase the level of multiplexing of electrochemical biosensors substantially. They used glass instead of silicon as a substrate, and lithographically patterned channels routed with reference and counter-electrode layers electrically insulated from subsequently electrodeposited tree-like working microelectrodes (also within the channels). A conductive solution in the channels makes contacts between the electrodes to form transient circuits. After functionalizing the working microelectrodes with pathogen-specific peptide nucleic acid probes, the researchers used these solution-based circuit chips to parallelize the quick detection and classification of 30 probes for pathogenic bacteria and antibiotic-resistance markers in unpurified samples. These chips should offer better scalability and be cheaper than standard molecular testing methods.