Elemental Mass Spectrometry and Fluorescence Dual-Mode Strategy for Ultrasensitive Label-Free Detection of HBV DNA
Beibei Chen, Guangyang Xiao, Man He, Bin Hu
Abstract
This work reported a simple and ultrasensitive label-free method for the detection of hepatitis B virus (HBV) DNA by combining hyperbranched rolling circle amplification (HRCA) with dual-mode detection by inductively coupled plasma mass spectrometry (ICP-MS) and fluorescence using ruthenium complex [Ru(bpy)2dppz]2+ (bpy = 2,2′-bipyridine, dppz = dipyrido [3,2-a:2′,3′-c] phenazine) as a dual functional probe. An HBV DNA-initiated HRCA system was designed to realize the highly efficient amplification of HBV DNA with the generation of a mass of dsDNA. Also, the [Ru(bpy)2dppz]2+ probe was then added to intercalate into the dsDNA products, resulting in strong fluorescence recovery of the probe for fluorescence detection. Meanwhile, using a biotin-modified primer in HRCA, the dsDNA-[Ru(bpy)2dppz]2+ complexes could be captured by the avidin-coated 96-well plates, and the captured [Ru(bpy)2dppz]2+ probe was later desorbed by acid for ICP-MS detection. The linear range of the proposed method was 3.5–200 amol L–1 and the limit of detection (LOD) was 1 amol L–1 for ICP-MS detection, while the linear range was 20–500 amol L–1 and the LOD was 9.6 amol L–1 for fluorescence detection. The developed method was applied to human serum sample analysis, and the analytical results coincided very well with those obtained by the real-time polymerase chain reaction (PCR) method. The developed dual-mode label-free detection method was ultrasensitive, simple, and accurate, showing great potential for therapeutic monitoring of HBV infection.