A Cascade Signal Amplification Strategy for the Ultrasensitive Fluorescence Detection of Cu<sup>2+</sup> via λ-Exonuclease-Assisted Target Recycling with Mismatched Catalytic Hairpin Assembly
Herein, an ultrasensitive DNAzyme-based fluorescence biosensor for detecting Cu<sup>2+</sup> was designed using the cascade signal amplification strategy, coupling λ-exonuclease-assisted target recycling and mismatched catalytic hairpin assembly (MCHA). In the designed detection system,...
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| Format: | Article |
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MDPI AG
2023-10-01
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| Series: | Biosensors |
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| Online Access: | https://www.mdpi.com/2079-6374/13/10/918 |
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| author | Zhen Liu Chen Liu Liqiong He Jinquan Liu Le Li Shengyuan Yang Yan Tan Xing Liu Xilin Xiao |
| author_facet | Zhen Liu Chen Liu Liqiong He Jinquan Liu Le Li Shengyuan Yang Yan Tan Xing Liu Xilin Xiao |
| author_sort | Zhen Liu |
| collection | DOAJ |
| description | Herein, an ultrasensitive DNAzyme-based fluorescence biosensor for detecting Cu<sup>2+</sup> was designed using the cascade signal amplification strategy, coupling λ-exonuclease-assisted target recycling and mismatched catalytic hairpin assembly (MCHA). In the designed detection system, the target, Cu<sup>2+</sup>, can activate the Cu<sup>2+</sup>-dependent DNAzyme to cause a cleavage reaction, releasing ssDNA (<i>t</i>DNA). Then, <i>t</i>DNA binds to hairpin DNA (H0) with an overhanging 5′-phosphorylated terminus to form dsDNA with a blunt 5′-phosphorylated terminus, which activates the dsDNA to be digested by λ-Exo and releases <i>t</i>DNA along with another ssDNA (<i>i</i>DNA). Subsequently, the <i>i</i>DNA initiates MCHA, which can restore the fluorescence of carboxyfluorescein (FAM) previously quenched by tetramethylrhodamine (TAMRA), resulting in a strong fluorescent signal. Furthermore, MCHA efficiently improves the signal-to-noise ratio of the detection system. More importantly, <i>t</i>DNA recycling can be achieved with the λ-Exo digestion reaction to release more <i>i</i>DNA, efficiently amplifying the fluorescent signal and further improving the sensitivity to Cu<sup>2+</sup> with a detection limit of 60 <i>f</i>M. The practical application of the developed biosensor was also demonstrated by detecting Cu<sup>2+</sup> in real samples, proving it to be an excellent analytical strategy for the ultrasensitive quantification of heavy metal ions in environmental water sources. |
| first_indexed | 2024-03-10T21:23:17Z |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-10T21:23:17Z |
| publishDate | 2023-10-01 |
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| series | Biosensors |
| spelling | doaj.art-2c0a79a9afd64b17b802cd57d9f740712023-11-19T15:51:18ZengMDPI AGBiosensors2079-63742023-10-01131091810.3390/bios13100918A Cascade Signal Amplification Strategy for the Ultrasensitive Fluorescence Detection of Cu<sup>2+</sup> via λ-Exonuclease-Assisted Target Recycling with Mismatched Catalytic Hairpin AssemblyZhen Liu0Chen Liu1Liqiong He2Jinquan Liu3Le Li4Shengyuan Yang5Yan Tan6Xing Liu7Xilin Xiao8Hunan Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, ChinaHunan Province Key Laboratory for Typical Environmental Pollution and Health Hazards, School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, ChinaHunan Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, ChinaHunan Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, ChinaHunan Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, ChinaHunan Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, ChinaHunan Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, ChinaHunan Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, ChinaHunan Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, ChinaHerein, an ultrasensitive DNAzyme-based fluorescence biosensor for detecting Cu<sup>2+</sup> was designed using the cascade signal amplification strategy, coupling λ-exonuclease-assisted target recycling and mismatched catalytic hairpin assembly (MCHA). In the designed detection system, the target, Cu<sup>2+</sup>, can activate the Cu<sup>2+</sup>-dependent DNAzyme to cause a cleavage reaction, releasing ssDNA (<i>t</i>DNA). Then, <i>t</i>DNA binds to hairpin DNA (H0) with an overhanging 5′-phosphorylated terminus to form dsDNA with a blunt 5′-phosphorylated terminus, which activates the dsDNA to be digested by λ-Exo and releases <i>t</i>DNA along with another ssDNA (<i>i</i>DNA). Subsequently, the <i>i</i>DNA initiates MCHA, which can restore the fluorescence of carboxyfluorescein (FAM) previously quenched by tetramethylrhodamine (TAMRA), resulting in a strong fluorescent signal. Furthermore, MCHA efficiently improves the signal-to-noise ratio of the detection system. More importantly, <i>t</i>DNA recycling can be achieved with the λ-Exo digestion reaction to release more <i>i</i>DNA, efficiently amplifying the fluorescent signal and further improving the sensitivity to Cu<sup>2+</sup> with a detection limit of 60 <i>f</i>M. The practical application of the developed biosensor was also demonstrated by detecting Cu<sup>2+</sup> in real samples, proving it to be an excellent analytical strategy for the ultrasensitive quantification of heavy metal ions in environmental water sources.https://www.mdpi.com/2079-6374/13/10/918Cu<sup>2+</sup> detectionλ-exonuclease-assisted target recyclingmismatched catalytic hairpin assemblycascade signal amplificationenvironmental pollutant |
| spellingShingle | Zhen Liu Chen Liu Liqiong He Jinquan Liu Le Li Shengyuan Yang Yan Tan Xing Liu Xilin Xiao A Cascade Signal Amplification Strategy for the Ultrasensitive Fluorescence Detection of Cu<sup>2+</sup> via λ-Exonuclease-Assisted Target Recycling with Mismatched Catalytic Hairpin Assembly Biosensors Cu<sup>2+</sup> detection λ-exonuclease-assisted target recycling mismatched catalytic hairpin assembly cascade signal amplification environmental pollutant |
| title | A Cascade Signal Amplification Strategy for the Ultrasensitive Fluorescence Detection of Cu<sup>2+</sup> via λ-Exonuclease-Assisted Target Recycling with Mismatched Catalytic Hairpin Assembly |
| title_full | A Cascade Signal Amplification Strategy for the Ultrasensitive Fluorescence Detection of Cu<sup>2+</sup> via λ-Exonuclease-Assisted Target Recycling with Mismatched Catalytic Hairpin Assembly |
| title_fullStr | A Cascade Signal Amplification Strategy for the Ultrasensitive Fluorescence Detection of Cu<sup>2+</sup> via λ-Exonuclease-Assisted Target Recycling with Mismatched Catalytic Hairpin Assembly |
| title_full_unstemmed | A Cascade Signal Amplification Strategy for the Ultrasensitive Fluorescence Detection of Cu<sup>2+</sup> via λ-Exonuclease-Assisted Target Recycling with Mismatched Catalytic Hairpin Assembly |
| title_short | A Cascade Signal Amplification Strategy for the Ultrasensitive Fluorescence Detection of Cu<sup>2+</sup> via λ-Exonuclease-Assisted Target Recycling with Mismatched Catalytic Hairpin Assembly |
| title_sort | cascade signal amplification strategy for the ultrasensitive fluorescence detection of cu sup 2 sup via λ exonuclease assisted target recycling with mismatched catalytic hairpin assembly |
| topic | Cu<sup>2+</sup> detection λ-exonuclease-assisted target recycling mismatched catalytic hairpin assembly cascade signal amplification environmental pollutant |
| url | https://www.mdpi.com/2079-6374/13/10/918 |
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