Protocol for the Use of a Silica Nanoparticle-Enhanced Microcantilever Sensor-Based Method to Detect HBV at Femtomolar Concentrations

DNA sensors that are capable of detecting specific DNA sequences in a bio-sample have recently been highlighted as a powerful and sensitive approach to detect infectious diseases caused by pathogens such as viruses and bacteria. Generally, DNA samples extracted from biological fluids are amplified by PCR prior to analysis by DNA sensors or directly analyzed by DNA sensors equipped with a signal amplification process. Nanoparticles have recently been used to amplify the sensor signal and have been shown to play an important role in improving the sensitivity of mechanical resonating sensors. This is because the weight of the nanoparticle can increase the change in the resonance response of the mechanical sensor since this signal change is closely related to mass. Here, we introduce an experimental method to detect HBV at femtomolar concentrations using a silica nanoparticle-enhanced microcantilever resonating sensor. This method includes the preparation of detection probe-conjugated silica nanoparticles, immobilization of capture probe on the microcantilever sensor and sandwich type detection of HBV DNA.