1. Polysaccharide-enhanced ARGET ATRP signal amplification for ultrasensitive fluorescent detection of lung cancer CYFRA 21-1 DNA
Xia Wang, Yawen Zhang, Liying Zhao, Dazhong Wang, Huaixia Yang, Jinming Kong Anal Bioanal Chem. 2020 Apr;412(11):2413-2421. doi: 10.1007/s00216-020-02394-1. Epub 2020 Feb 11.
An ultrasensitive fluorescence biosensor for detecting cytokeratin fragment antigen 21-1 (CYFRA 21-1) DNA of non-small cell lung carcinoma (NSCLC) is designed using polysaccharide and activator regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) signal amplification strategy. Thiolated peptide nucleic acid (PNA) is fixed on magnetic nanoparticles (MNPs) by a cross-linking agent and hybridized with CYFRA 21-1 DNA. Hyaluronic acid (HA) is linked to PNA/tDNA heteroduplexes in the form of carboxy-Zr4+-phosphate. Subsequently, multiple 2-bromo-2-methylpropionic acid (BMP) molecules are linked with HA to initiate ARGET ATRP reaction. Finally, a large number of fluorescein o-acrylate (FA) monomers are polymerized on the macro-initiators, and the fluorescence signal is significantly amplified. Under optimal conditions, this biosensor shows a significant linear correlation between the fluorescence intensity and logarithm of CYFRA 21-1 DNA concentration (0.1 fM to 0.1 nM), and the limit of detection is as low as 78 aM. Furthermore, the sensor has a good ability to detect CYFRA 21-1 DNA in serum samples and to recognize mismatched bases. It suggests that the strategy has broad application in early diagnosis by virtue of its high sensitivity and selectivity. Graphical abstract A novel and highly sensitive fluorescence biosensor for quantitatively detecting CYFRA 21-1 DNA via dual signal amplification of hyaluronic acid and ARGET ATRP reaction was developed. This proposed method has a low detection limit, wide detection range, high selectivity, and strong anti-interference.
2. Ultrasensitive DNA biosensor based on electrochemical atom transfer radical polymerization
Haobo Sun, Yunliang Qiu, Qianrui Liu, Qiangwei Wang, Yan Huang, Dongxiao Wen, Xueji Zhang, Qingyun Liu, Guodong Liu, Jinming Kong Biosens Bioelectron. 2019 Apr 15;131:193-199. doi: 10.1016/j.bios.2018.11.029. Epub 2018 Nov 19.
Here we report a highly selective and ultrasensitive DNA biosensor based on electrochemical atom transfer radical polymerization (ATRP) signal amplification and "Click Chemistry". The DNA biosensor was prepared by immobilizing thiol and azide modified hairpin DNAs on gold electrode surface. In the presence of target DNAs (T-DNA), hairpin probes hybridized with T-DNAs to form a duplex DNA, and the ring of hairpin DNA was opened to make azide groups accessible at 3' ends. "Click reactions" proceeded between the azide and propargyl-2-bromoisobutyrate (PBIB) to initiate the ATRP reaction which brought a large number of ferrocenylmethyl methacrylate (FMMA) on the electrode surface. The amount of FMMA was proportional to the concentration of T-DNA and quantified by square wave voltammetry. Combining ATRP signal amplification with "Click Chemistry", the optimized DNA biosensor was capable of detecting 0.2 aM. T-DNA. The preliminary application of the developed DNA biosensor was demonstrated by detecting target DNA in spiked serum samples. The developed DNA biosensor shows great promise for the detection of gene biomarkers.
3. Hairpin probes based click polymerization for label-free electrochemical detection of human T-lymphotropic virus types II
Di Cheng, Yaping Zhang, Dongxiao Wen, Zhuangzhuang Guo, Huaixia Yang, Yanju Liu, Jinming Kong Anal Chim Acta. 2019 Jun 20;1059:86-93. doi: 10.1016/j.aca.2019.01.027. Epub 2019 Jan 25.
A novel, simple, and label-free amplification electrochemical impedance method for quantitative detection of Human T-lymphotropic virus types II(HTLV-II) via click chemistry-mediated of hairpin DNA probes (hairpins) with polymers was developed. The hairpins were firstly attached to the gold electrode surface by an S-Au bond, the azido terminals of hairpins were close to the electrode surface, which make it difficult to be approached. After hybridizing with HTLV-II, the hairpins were unfolded and experienced a big configuration change, which made the azido terminals of the hairpins available to conjugate with alkynyl-containing polymer, called P(DEB-DSDA), formed by 1,4-diacetylenebenzene (DEB) and 4,4'-Diazido-2,2'-stilbenedisulfonic acid disodium salt tetrahydrate (DSDA) via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC). With amount of P(DEB-DSDA) conjugated with the hairpin probes via click polymerization, its electrochemical signal can have a great amplification. Under optimized experimental conditions, this new probe showed a low detection limit of 0.171 pM with a good liner in the range of 1 pM-1 nM. Meanwhile, the biosensor also exhibited good selectivity and reliability in detection of real serum samples, indicating that it has great application potential in clinical DNA diagnosis and detection.
