Abstract:
Influenza A viruses typically circulate annually among people worldwide, which poses great threat to public healthdue to its high transmissibility. Rapid detection of influenza A viruses is essential for early intervention and outbreak control. While Reverse Transcription Polymerase Chain Reaction (RT-PCR) provides excellent analytical performance, its reliance on sophisticated instrumentation and trained operators limits its application in on-site rapid screening. Antigen-based assays offer rapidity but typically lack the sensitivity required for early-stage infection hence often show false negative results. To address these limitations, we developed a smartphone-assisted electrochemical biosensor platformfor sensitive and portable detection of influenza A virus.
The sensing approach utilizes screen-printed electrodes (SPEs) in combination with magnetic beads-immobilized DNA probes for the capture, isolation, and detection of virus nucleic acids, while a smartphone is used for signal processing and results display. We first used complementary DNA (cDNA) as the target to verify the feasibility of the platform and then applied it in clinical samples’ detection. To realize signal transduction, methylene blue (MB) is adopted to intercalate into the formed double-stranded nucleic acid strand and generates quantifiable redox currents. As the redox signal from MB alone is relatively weak, several strategies have been explored for MB current signals amplification, such as addition of [Fe(CN)?]3-/4- in electrolyte or using prussian blue (or its analogues, PB/PBA) as mediator layer on SPEs. Current responses are recorded using a smartphone based potentiostat, providing a compact and accessible platform for on-site electrochemical analysis.
We have found that by adopting [Fe(CN)?]3-/4- in the electrolyte as amplifier for MB, the signal strength can be increased 3 times compared with the one without it. While using PBA as the mediator layer, the signal strength can be increased 50 times. Finally, we have evaluated the linear detection range and limit of detection of our platform, which delivers a broad linear detection range from 0.5 aM to 100 nM and an ultra low limit of detection of 2.01 aM. This sensitivity is comparable to the analytical performance of RT-PCR. Most importantly, no nucleic acid amplification step is involved in the whole assay, thus a single run can be completed in less than 1 hour. These results highlight the strong potential of our platform for rapid and accurate influenza diagnostics.
In summary, this work demonstrates a smartphone based electrochemical nucleic acid sensing platform that integrates magnetic beads assisted capture with a portable electrochemical readout. The approach with its rapidity, high sensitivity, operational simplicity represents a promising technology for next-generation point-of-care testing for infectious diseases.
Biography:
Jianghong Wu is an associate professor of Shenzhen Technology University, specializing in rapid detection technology for infectious disease. She received her Ph.D. (2013) from the Department of Materials Science and Engineering at Donghua University. She then joined the State Key Laboratory of Chemo/ Biosensing and Chemometrics at Hunan University as a postdoc. Her research focuses on electrochemical biosensors for rapid detection, early diagnosis and health monitoring.
