Highly sensitive plasmonic biosensor for hepatitis B virus DNA based on the surface etching of the active helical gold nanorods

As one of the most prominent global public health problems, which seriously threats public health security and human health, hepatitis B virus (HBV) infection is the main cause of liver cirrhosis and cancer. Herein, an innovative and sensitive biosensor for HBV-DNA detection was developed based on the surface etching of the helical gold nanorods (HGNRs) at single-particle level under a dark-field microscope (DFM). In this work, the unique HGNRs with high surface activity were functionalized as the optical probe, which were etched to the smooth gold nanorods and even to gold nanospheres, resulting in a distinct color and light scattering change of single particle with a more sensitive result of HBV-DNA detection than the common gold nanorods. Furthermore, the hybridization chain reaction amplification and DFM technique enabled the proposed strategy with a high sensitivity, offering the limit of detection (LOD) as low as 30.15 fM (3σ/k) and realizing sensitive detection of HBV-DNA from 0.05 to 10 pM. Moreover, the proposed strategy supplied the good specificity, which was capable of distinguishing mismatch sequence and other viral nucleic acids. In addition, this strategy was universal and provided a new idea for early diagnosis of other viral nucleic acids, such as hepatitis C virus (HCV) and human immunodeficiency virus (HIV).