Rolling circle amplification combined with gold nanoparticles-tag for ultra sensitive and specific quantification of DNA by inductively coupled plasma mass spectrometry.

A novel method for the ultra specific and sensitive detection of DNA in biological samples was described in this paper based on magnetic beads (MBs)-based rolling circle amplification combined with gold nano-particles (AuNPs)-aptamer labeling technique and inductively coupled plasma mass spectrometry (ICP-MS) detection. The proposed assay has an ultra-high sensitivity and stability, excellent specificity and more robust resistibility to the complex matrix due to the utilization of MBs-based rolling circle amplification, AuNPs-aptamer labeling technique and ICP-MS detection. It can be used to determine DNA or single nucleotide polymorphisms (SNP) with an extremely low detection limit of 0.1fM (1.0×10(-16)M) and a discrimination factor for single-base mismatch of 27. The proposed assay has been successfully used to detect DNA in serum sample with a recovery of 91-106% and a relative standard deviation (RSD) <6% (n=6), suggesting that our method is sensitive and reliable. The ultra-high sensitivity and specificity, easiness of fabrication, operational convenience, short analysis time, better stability and robust resistibility to the complex matrix, make the assay a promising alternative for the detection of various DNA sequence in the clinical diagnosis.