Dual-enzyme cascade amplification electrochemical biosensor for human papillomavirus based on DNA nanoflower structure

The lack of large-scale human papillomavirus (HPV) DNA screening is a major contributor to the high incidence and mortality of cervical cancer in economically undeveloped areas. The development of sensitive, rapid, and low-cost screening techniques is urgently needed. Here, DNA nanoflowers encapsulating glucose oxidase and horseradish peroxidase (GHDFs) were synthesized by one-pot rolling circle amplification, and then the GHDFs were used as the cargo of DNA hydrogel and applied for HPV DNA detection. When target DNA was present, the DNA hydrogel cross-linking structure was disrupted, releasing GHDFs, which then catalysed the oxidation of glucose and tetramethylbenzidine in a cascade, generating a significant electrical signal. Signal intensity had a linear relationship with the logarithm of target DNA concentration in the range of 10 fM-1 nM with a detection limit of 3.76 fM. The detection time of the proposed biosensor was 25 min, which was suitable for large-scale HPV DNA screening in economically underdeveloped areas and provides a blueprint for the detection of other DNA of interest.