College of Life Science, Shaanxi Normal University, Xi'an,China.
College of Life Science, Shaanxi Normal University, Xi'an,China | School of Computer Sciences, Shaanxi Normal University, Xi'an, P.R. China.
Comb Chem High Throughput Screen. 2022;25(4):651-657. doi: 10.2174/1386207324666210216095053.
Molecular logic gate always makes use of fluorescent dyes to realize fluorescence signals. The labeling of the fluorophore is relatively expensive, resulting in low yield, and singly labeled impurities affect the affinity between the target and the aptamer. Label-free fluorescent aptamer biosensor strategy has attracted widespread interest due to lower cost and simplicity.
Herein, we have designed an AND logic gate fluorescent aptasensor for detecting carbohydrate antigen 15-3(CA15-3) based on label-free fluorescence signal output.
A hairpin DNA probe consists of CA15-3 aptamer and partly anti-CA15- 3 aptamer sequences as a long stem and G-rich sequences of the middle ring as a quadruplexforming oligomer. G-rich sequences can fold into a quadruplex by K+, and then G-quadruplex interacts specifically with N-methylmesoporphyrin IX(NMM), leading to a dramatic increase in fluorescence of NMM. With CA15-3 and NMM as the two inputs, the fluorescence intensity of the NMM is the output signal. Lacking CA15-3 or NMM, there is no significant fluorescence enhancement, and the output of the signal is "0". The fluorescence signal dramatically increases and the output of the signal is "1" only when CA15-3 protein and NMM are added at the same time.
This biosensor strategy was observed to possess selectivity and high sensitivity for detecting CA15-3 protein from 10 to 500 U mL-1 and the detection limit was found to be 10 U mL-1, which also showed good reproducibility in spiked human serum.
In summary, the proposed AND logic gate fluorescent aptasensor could specifically detect CA15-3.
分子逻辑门通常利用荧光染料来实现荧光信号。荧光染料的标记较为昂贵，导致产量较低，且单标记杂质会影响靶标与适体之间的亲和力。无标记荧光适体生物传感器策略由于成本较低且简单而引起了广泛关注。
本文设计了一种基于无标记荧光信号输出的用于检测糖链抗原 15-3（CA15-3）的与门逻辑门荧光适体传感器。
发夹 DNA 探针由 CA15-3 适体和部分抗 CA15-3 适体序列作为长茎以及中间环的富含 G 的序列作为四链形成寡聚物组成。富含 G 的序列可以通过 K+折叠成四链体，然后 G-四链体与 N-甲基甲川卟啉 IX（NMM）特异性相互作用，导致 NMM 的荧光显著增强。以 CA15-3 和 NMM 作为两个输入，NMM 的荧光强度为输出信号。缺乏 CA15-3 或 NMM 时，没有明显的荧光增强，信号输出为“0”。只有当同时加入 CA15-3 蛋白和 NMM 时，荧光信号才会显著增加，信号输出为“1”。
该生物传感器策略被观察到对 10 至 500 U mL-1 的 CA15-3 蛋白具有选择性和高灵敏度，检测限为 10 U mL-1，在添加人血清中也表现出良好的重现性。
总之，所提出的与门逻辑门荧光适体传感器可以特异性地检测 CA15-3。
