In this work, a label-free fluorescence biosensor for simple detection of the HIV-1 gene was proposed by using toehold-mediated strand displacement reactions (TMSDRs) combined with a non-enzymatic target recycling amplification strategy. In this system, two TMSDRs were used. In the presence of the HIV-1 gene, an autocatalytic DNA machine can be activated. This leads to the generation of numerous free G-rich sequences, which can associate with a fluorescent dye N-methylmesoporphyrin IX (NMM) to yield an amplified fluorescence signal for the target detection. This sensing platform showed a high sensitivity towards the HIV-1 gene with a detection limit as low as 1.9 pM without any labelling, immobilization, or washing steps. The designed sensing system also exhibits an excellent selectivity for the HIV-1 gene compared with other interference DNA sequences. Furthermore, the presented biosensor is robust and has been successfully applied for the detection of the HIV-1 gene in a real biological sample with satisfactory results, suggesting that this method is promising for simple and early clinical diagnosis of HIV infection. Thanks to its simplicity, cost-effectiveness and ultrasensitivity, our proposed sensing strategy provides a universal platform for the detection of other genes by substituting the target-recognition element. Publication name | ANALYST, 144 (6):2173-2178; 10.1039/c8an02340a MAR 21 2019 | Author(s) | Li, Qiong; Liu, Zhi; Zhou, Danhua; Pan, Jiafeng; Liu, Chengshuai; Chen, Junhua | Corresponding author(s) | CHEN Junhua 222chenjunhua@163.com Guangdong Inst Ecoenvironm & Sci & Technol, Guangdong Key Lab Integrated Agroenvironm Pollut, Guangzhou 510650, Guangdong, Peoples R China. | Author(s) from IGCAS | LIU Chengshuai | View here for the details
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