Rapid Detection of Virus Nucleic Acid via Isothermal Amplification on Plasmonic Enhanced Digitizing Biosensor

Rapid detection for infectious diseases is highly demanded in diagnosis and infection prevention. In this work, we introduced a plasmonic enhanced digitizing biosensor for the rapid detection of nucleic acids. The sensor successfully achieved the detection of loop-mediated isothermal amplification for the hepatitis virus in this work. The sensor comprised a nanodisc array and Bst polymerases conjugated on the rough surface of a nanodisc. The rough surface of the nanodisc provided plasmonic hot spots to enhance the fluorescence signal. The virus DNA was detected by conducting a modified loop-mediated isothermal amplification with fluorescence resonance energy transfer reporter conjugated primers on the sensor. The modified isothermal amplification improved the signal contrast and detection time compared to the original assay. By integrating the modified amplification assay and plasmonic enhancement sensor, we achieved rapid detection of the hepatitis virus. Nucleic acid with a concentration of 10^-3 to 10^-4 mg/mL was detected within a few minutes by our design. Our digitizing plasmonic nanoarray biosensor also showed 20-30 min earlier detection compared to conventional loop-mediated isothermal amplification sensors.