Abnormal concentration of adenosine triphosphate (ATP) is directly asscociate with several diseases. Thus, sensitive detection of ATP is essential to early diagnosis of disease. Herein, we described an ultrasensitive strategy for ATP detection by using positively charged gold nanorods ((+)AuNRs) as an efficient fluorescence quenching platform, coupled with exonuclease Ⅲ (Exo Ⅲ) assisted target recycling amplification. To construct the sensor, DNA template that contained ATP aptamer was used for the formation of Ag nanoclusters signal probe (DNA/AgNCs), the structure of it could change to duplex after the interaction of it with ATP. Such DNA template or duplex DNA product could electrostatically adsorb onto (+)AuNRs surface, resulting in the quenching of the fluorescence signal due to the vicinity of AgNCs to (+)AuNRs. With the addition of Exo Ⅲ, DNA duplex could be hydrolyzed and released from (+)AuNRs surface, leading to the recovery of a strong fluorescent signal, while ATP could be regenerated for next target recycling. Combing the good fluorescence quenching ability of (+)AuNRs and the Exo Ⅲ assisted signal amplification, a low detection limit of 26 pM was achieved for ATP detection. Notably, the proposed method can be successfully applied for detecting ATP in serum samples, indicating a potential application value in early cancer diagnosis.
Yaoyao Xie,Zhimin Guan,Huikai Ma,Ping Wang,Shoumin Xi
In this work, we developed a novel ratiometric electrochemical aptasensor for the sensitive detection of carcinoembryonic antigen (CEA). Upon the addition of CEA, the specific binding between CEA and hairpin probe 1 (HP1) could trigger the Exo Ⅲ cleavage reaction and release large amounts of single stranded DNA (S1), which then hybridized with thiolated ferrocene-labeled hairpin probe 3 (Fc-HP3) on the electrode surface. Exo Ⅲ then cyclically digested the resulting duplexes to generate Fc-HP3 fragments on the electrode, accompanying the Fc molecules far away from the electrode surface and the Fc oxidation peak current signal (I Fc ) decreased. The HCR process was triggered by the Fc-HP3 fragment as an initiator, producing many long DNA sequences for electroactive probe methylene blue (MB) intercalation; thus, the MB oxidation peak current signal (I MB ) increased. The I MB /I Fc ratio was proportional to the logarithm value of CEA concentration from 100 fg mL −1 to 50 ng mL −1 , with a lower detection limit of 30.5 fg mL −1 . Furthermore, the aptasensor exhibited good selectivity and stability, with satisfactory reproducibility. Additionally, the developed aptasensor effectively measured CEA in real serum samples, verifying its practical application in biological samples.
Liang Tian,Jiyuan Zhang,Huiling Fan,Yanci Zhang,Zhanhui Wang,Olayinka Oderinde,Yihong Wang,Jiansheng Cui
A target-triggered and exonuclease-Ⅲ-assisted strand displacement, dual-recycling amplification reaction-based biosensor was developed for the rapid, ultrasensitive and accurate detection of kanamycin . The robust profiling platform was constructed using high conductive MXene/VS 2 for the electrode surface modification and high active CeCu 2 O 4 bimetallic nanoparticles as nanozyme to improve the sensitivity as well as the catalytic signal amplification of the biosensor. Using the dual supplementary recycling of primer DNA and hairpin DNA , the electrochemical platform could accurately detect kanamycin to as low as 0.6 pM from the range of 5 pM to 5 μM. By profiling five other antibiotics, this platform exhibited high specificity, enhanced repeatability and reproducibility. Based on these intrinsic characteristics and by utilizing milk and water samples, the as-designed biosensor offers a remarkable strategy for antibiotic detection due to its favorable analytical accuracy and reliability, thereby demonstrating potential application prospect for various antibiotic biosensing in food quality control, water contamination detection and biological safety analysis.
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