Visual detection of DNA from salmonella and mycobacterium using split DNAzymes

The split G-quadruplex DNAzyme has emerged as a valuable tool for visual DNA detection. Most reports on its use have however been constrained to proof-of-concept demonstrations using synthetic oligonucleotides. This is due to the inherent complexities of the assay, and the multiple components involved. Herein, we have overcome several of these challenges and have successfully integrated asymmetric PCR with the visual detection step, allowing enriched targets from complex samples to be conveniently detected. This workflow would enable the DNAzyme system to be applied for point-of-care DNA detection applications. We have established the platform herein as a simple and robust method to determine the presence of target DNA sequences post-PCR (as required for pathogen detection), without the need for gels or other apparatus. Nanomolar concentrations of amplified targets were detected using the workflow established, enabling the detection of salmonella and mycobacterium targets through a color change reaction, observable just by eye.