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A highly sensitive assay of DNA based on inductively coupled plasma mass spectrometry detection with gold nanoparticle amplification and isothermal circular strand-displacement polymerization reaction
- Xiao, Guangyang, Chen, Beibei, He, Man, Li, Xiaoting, Hu, Bin
- Talanta 2019 v.202 pp. 207-213
- DNA, atomic absorption spectrometry, biotin, blood serum, chemical bonding, desorption, enzymatic reactions, humans, magnetism, nanogold, polymerization, standard deviation, streptavidin
- In this work, a simple, sensitive and specific assay for DNA was proposed by combining inductively coupled plasma mass spectrometry (ICP-MS) detection with gold nanoparticle (AuNPs) amplification and isothermal circular strand-displacement polymerization reaction (ICSDPR). First, AuNPs were decorated with hairpin-structured DNA (HP-DNA) through Au–S bond to form the AuNPs probe. The ICSDPR was conducted on AuNPs probe in a homogeneous phase to realize the dual amplification and simplify the analytical process at the same time. By using a biotin modified primer, AuNPs were connected with biotins after the ICSDPR, then captured by the streptavidin modified magnetic beads (SA-MBs), and finally detected by ICP-MS. Many key factors including probe volume, hybridization time, polymerase amount, primer concentration, enzyme reaction time, SA-MBs capture time and desorption time were optimized. Under the optimized condition, the proposed method could detect target DNA as low as 45 zmol (8.9 fM in 5 μL) in a relative short time (about 4.5 h) with good specificity, and the linear range of this method is 0.1–10000 pM, the relative standard deviations are in the range of 3.6–6.4%. The proposed method was applied for determination of target DNA in human serum samples, the recovery for the spiked human serum samples is in the range of 84–120%. It demonstrates a good application potential of the developed method for biological studies and clinical diagnosis of human pathogenic diseases.