Ling Yang,Ping’an Ma,Xiaorui Chen,Ziyong Cheng,Jun Lin
Sensitive detection of circulating tumor DNA (ctDNA) in vitro has attracted growing attention owing to its potential application in diagnostics of cancer. In this study, we synthesized hydrophilic AgInS2@ZnS core–shell quantum dot nanocrystals and magnetic Fe3O4 nanoparticles, and then the ctDNA triggered hybridization chain reaction was used to detect the CYFRA21-1 DNA associated with lung cancer. In the presence of CYFRA21-1 DNA, three hairpin structures were activated to turn on successively, resulting in the accumulation of quantum dots and eliciting considerable changes of the fluorescence signal. Compared with the conventional fluorescence detection, Fe3O4 provides magnetic adsorption properties and a large surface area for immobilizing and aggregating quantum dot nanoparticles attached to single-stranded DNA. The concentration of CYFRA21-1 is closely related to the number of quantum dots remaining after magnetic adsorption, which provides a promising approach for ctDNA quantification.
Li Jinge,Zhao Liying,Wen Dongxiao,Li Xiaofei,Yang Huaixia,Wang Dazhong,Kong Jinming
In this work, a new method of CYFRA21-1 DNA (tDNA) detection based on electrochemically mediated atom transfer radical polymerization (e-ATRP) and surface-initiated reversible addition-fragmentation chain transfer polymerization (SI-RAFT) cascade polymerization and AgNP deposition is proposed. Firstly, the peptide nucleic acid (PNA) probe is captured on a gold electrode by Au-S bonds for specific recognition of tDNA. After hybridization, PNA/DNA strands provide high-density phosphate groups for the subsequent ATRP initiator by the identified carboxylate-Zr 4+ -phosphate chemistry. Then, a large number of monomers are successfully grafted from the DNA through the e-ATRP reaction. After that, the chain transfer agent of SI-RAFT and methacrylic acid (MAA) are connected by recognized carboxylate-Zr 4+ -carboxylate chemistry. Subsequently, through SI-RAFT, the resulting polymer introduces numerous aldehyde groups, which could deposit many AgNPs on tDNA through silver mirror reaction, causing significant amplification of the electrochemical signal. Under optimal conditions, this designed method exhibits a low detection limit of 0.487 aM. Moreover, the method enables us to detect DNA at the level of PCR-like and shows high selectivity and strong anti-interference ability in the presence of serum. It suggests that this new sensing signal amplification technology exhibits excellent potential of application in the early diagnosis of non-small cell lung cancer (NSCLC).
Electrochemical detection principle for CYFRA21-1 DNA based on e-ATRP and SI-RAFT signal amplification technology.
Kai Hu,Jiamin Cheng,Jinge Li,Shan Ye,Huaixia Yang,Yanju Liu,Jinming Kong
The sensitive detection of biomarker cytokeratin fragment antigen 21-1 (CYFRA21-1) is crucial for early diagnosis and screening of non-small cell lung cancer (NSCLC). In this work, an electrochemical biosensor based on Nafion-initiated eATRP has been built for ultrasensitive detection of CYFRA21-1 DNA for the first time. Specifically, peptide nucleic acid (PNA) probes are immobilized onto a gold electrode surface and then hybridized with target DNA to form PNA/DNA heteroduplexes for the subsequent attachment of Nafion by the identified carboxyl–Zr4+–phosphoric acid chemistry. Finally, polymer chains are obtained by linking the monomer of ferrocenylmethyl methacrylate to the PNA/MCH/DNA/Zr4+/Nafion probes via eATRP. Under optimized steady-state conditions, the sensor offers a wide current response for CYFRA21-1 DNA from 10−11 to 10−16 M with a detection limit of 6.42 × 10−17 M. The proposed method of using Nafion as the eATRP initiator exhibits high sensitivity, reproducibility and stability and is a promising strategy for early diagnosis of NSCLC.
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