Center of AIE Research, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, PR China.
Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, 100101, PR China.
Anal Chim Acta. 2021 Dec 15;1188:338859. doi: 10.1016/j.aca.2021.338859. Epub 2021 Jul 21.
Bioassays using a fluorophore and DNA aptamer have been extensively developed due to the ultrasensitivity of fluorophores and recognition ability of DNA aptamers. Conventional fluorescent aptamer-based sensors (aptasensors) require chemical labeling between the fluorophore and aptamer and is technologically impracical for various sensing and assay applications. A simple "mix and go" strategy has been introduced that uses label-free technology as a platform for sensor development. The biosensors comprise a fluorophore, a ssDNA aptamer, and eco-friendly graphene oxide (GO). In the absence of the sensor target, GO quenches the fluorescence of the fluorophore and single-strand DNA aptamer complex. When the target is added, the DNA aptamer conformationally turns into a duplex, G-quadruplexe, or other secondary structure. This structure change leads to release of GO by the fluorophore-aptamer-target complex, generating dramatic fluorescence recovery and amplification. With this sensing method, the DNA aptamer does not need to be chemically labeled. Therefore, flexible fluorophore indicators and ssDNA aptamers can be used in this label-free aptasensing strategy. In this review, we discuss various unlabeled fluorophores, including synthetic small molecular fluorophores and genetically encoded fluorescent proteins, as indicators for generating GO-based fluorescent DNA aptasensors for label-free bioassay.
由于荧光团的超高灵敏度和 DNA 适体的识别能力，使用荧光团和 DNA 适体的生物测定法得到了广泛的发展。传统的荧光适体基传感器（适体传感器）需要在荧光团和适体之间进行化学标记，对于各种传感和分析应用来说，这在技术上是不切实际的。现在已经引入了一种简单的“混合即走”策略，该策略将无标记技术用作传感器开发的平台。该生物传感器由荧光团、ssDNA 适体和环保型氧化石墨烯（GO）组成。在没有传感器目标的情况下，GO 会猝灭荧光团和单链 DNA 适体复合物的荧光。当添加目标时，DNA 适体构象转变成双链体、G-四联体或其他二级结构。这种结构变化导致荧光团-适体-靶复合物释放 GO，从而产生显著的荧光恢复和放大。使用这种传感方法，DNA 适体不需要进行化学标记。因此，灵活的荧光团指示剂和 ssDNA 适体可以用于这种无标记适体传感策略。在本综述中，我们讨论了各种未标记的荧光团，包括合成小分子荧光团和遗传编码荧光蛋白，它们可作为基于 GO 的无标记荧光 DNA 适体传感器生成的指示剂，用于无标记生物测定。
