Background We have developed a novel Point-of-Care molecular assay system, io™, comprising an assay-specific Cartridge and Reader. With a turnaround time of just 30 minutes the System has an initial focus on rapidly detecting sexually-transmitted infections (STIs). The System has been developed to run tests that simultaneously detect Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG), each run with an internal control (IC). The assays utilise a novel electrochemical method that demonstrates low copy number amplification and detection. Here, we have developed a CT/NG/IC triplex assay where each target analyte is co-amplified prior to being differentially detected.

Methods The assays were run using prototype PCR Cartridges in conjunction with an ultra-rapid thermocycler. All reagents necessary to perform the assay were deposited into the Cartridge. A sample was added to the Cartridge, DNA extracted, and the resulting eluate reconstituted dried amplification reagents. Amplified targets were detected using electrochemically-labelled target-specific probes and a double-stranded DNA-specific nuclease to release the electrochemical labels. Released labels were detected by applying a voltage to a screen-printed carbon electrode. Measurable current at specific oxidation potentials indicated the presence of targets in the sample.

Results Initial analytical sensitivity of the triplex CT/NG/IC assay was evaluated by testing each target analyte in combination with various concentrations of the other two (including negative controls). Electrochemical detection demonstrated clear differentiation between peaks generated by each cleaved label and showed a limit of detection of ten genome copies. Negative samples showed no significant peaks.

Conclusions The results showed that reliable, differentiated detection of three targets in a single sample was possible across a wide range of concentrations of the three targets. While demonstrated here for three analytes, the Atlas high-multiplex technology will allow expansion of the Atlas io™ test menu to detect multiple STIs in a single sample.