Liu Wenwen,Ma Ligang,Guo Zhuangzhuang,Liu Tao,Liu Yanju,Wang Dazhong,Kong Jinming
We propose a novel, ultrasensitive and low-cost sensor using reversible addition-fragmentation chain transfer (RAFT) polymerization as a signal amplification strategy for the detection of CYFRA 21-1 DNA fragment, a tumor marker of non-small cell lung carcinoma. The peptide nucleic acid (PNA) probes were firstly immobilized on magnetic beads (MBs) to capture the CYFRA 21-1 DNA specifically. After hybridization, CPAD was tethered to the hetero duplexes through carboxylate-Zr 4+ -phosphate chemistry. Subsequently, a number of fluorescent tags were introduced to the heteroduplexes through RAFT polymerization, leading to an amplification of the fluorescence signal. The sensor demonstrates a low limit of detection (LOD) of 0.02 fM. It has great selectivity with respect to base mismatch DNA, and high anti-interference ability in normal human serum. Overall findings of the study suggest that proposed sensor holds enormous potential to be used as a tool for the early-stage diagnosis of lung cancers.
Ruijiang Liu,Shuai Pan,Min Liu,Wei Huang,Zhixiang Lv,Aolin He
A label-free electrochemical biosensor with magnetically induced self-assembly based on peptide nucleic acids (PNA) and Fe 3 O 4 /Fe 2 O 3 heteroplasmon nanorods was successfully fabricated to detect the single nucleotide polymorphism (SNP) of CYP2C9*3. The sensitivity of the electrochemical biosensor was improved by introducing PNA and Fe 3 O 4 /Fe 2 O 3 @Au nanocomposites. The Fe 3 O 4 /Fe 2 O 3 @Au nanocomposites were assembled on the surface of the magnetic glassy carbon electrode (MGCE) by magnetic field, and the thiolated PNA were connected to the nanocomposites through Au-S bonds. The biosensor exhibited a good linear correlation between 1 pM and 1 µM (R 2 = 0.9941), and the limit of detection (LOD) and the limit of quantitation (LOQ) were 0.95 pM and 3.18 pM, respectively. Besides, the electrochemical biosensor could recognize single-base mismatch DNA, and it could be stored stably for 15 days at 4 °C.
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