Flexible Electrochemical Biosensor Using Nanostructure-Modified Polymer Electrode for Detection of Viral Nucleic Acids

In the biosensor field, the accurate detection of contagious disease has become one of the most important research topics in the post-pandemic period. However, conventional contagious viral biosensors normally require chemical modifications to introduce the probe molecules to nucleic acids such as a redox indicator, fluorescent dye, or quencher for biosensing. To avoid this complex chemical modification, in this research, mismatched DNA with an intercalated metal ion complex (MIMIC) is employed as the probe sequence. In addition, the MIMIC is fabricated on a lithography-assisted nanostructure-modified flexible polymer electrode. On this flexible electrode, as a proof-of-concept study, a human papillomavirus (HPV-16 and -18) was detected by the MIMIC with a high accuracy. The developed biosensor exhibits an ultrasensitive ability to detect HPV in viral DNA without target amplification and chemical modifications in a simple preparation manner. Moreover, it retains its nanostructures and high conductivity after bending. In conclusion, the use of the proposed biosensor suggests a novel approach to developing an ultrasensitive and flexible biosensor for the detection of important biomarkers in a simple manner that can be applied in point-of-care testing.