Hai-Bo Wang,Li-Hong Ma,Bi-Yun Fang,Fang Tan,Yuan-Cheng Cao,Yuan-Di Zhao,Xue-Bin Hu
PS2M aptamer was selected as sensing element to construct Pb 2+ strip biosensor, and for the first time, AuNP-DNA polymer was used as sensitivity enhancement probe (SEP) to improve sensitivity. Pb 2+ separated the double-strand formed by PS2M and its complementary sequence at Anti-PS2M and induced PS2M to form G-quadruplex structure, then single-strand Anti-PS2M was released. When migrated along the strip, sequence at one end of Anti-PS2M hybridized with AuNP-DNA probe G immobilized on conjugate pad, when the composite migrated to test zone (TZ), other end of Anti-PS2M hybridized with biotin-DNA probe T on TZ to form sandwich structure. Subsequent SEP hybridized with the remaining oligonucleotides of AuNP-DNA probe G on TZ thus enhanced the signal. After optimization, the false positive result could be eliminated and the best signal value could be obtained. The results showed that the limit of detection of Pb 2+ strip biosensor was 2.5 nM by adding the sensitivity enhancement probe, which was 40 times better than that strip without enhancement. The test strip showed good results in the direct detection of soil and lake samples, presenting good practical value. In addition, the cost of this strip biosensor was low, with good market prospect.
The p53 gene is a known cancer marker. We report a novel protocol for the SERS tandem strategy to detect the p53 gene with high sensitivity. Herein, the click reaction between azide and alkyne was catalyzed by utilizing copper oxide nanoparticles (CuONPs), which were enriched by a T-DNA-triggered hybridization chain reaction (HCR). The T-DNA signal was amplified by establishing the correlation between the T-DNA signal and the concentration of CuONPs in a nonenzymatic isothermal environment. In contrast to other Raman reporters, we used alkynyl compounds as Raman reporters, which showed excellent characteristics in the Raman-silent region (1800–2800 cm −1 ). Therefore, the highly sensitive and highly selective SERS signals could be obtained in complex biological matrices. Due to utilizing multistep amplification strategies, including the nanoparticle-modified HCR polymer and “click” reaction, the limit of detection (LOD) and the limit of quantification (LOQ) of this sensor could be as low as 0.0174 pM and 0.0583 pM, respectively. The accuracy of the strategy expressed as the RSD was in the range of 3.14%–6.21%. The results indicated that the constructed sensor has excellent performance for the detection of the p53 gene in serum samples in a low concentration range, which suggests that the proposed enzyme-free SERS analytical sensor has good clinical application prospects.
危险品化学品经营许可证（带存储）