作者机构：
[Ning, Yi; Lu, Fangguo; Hu, Jue] Hunan Univ Chinese Med, Med Sch, Dept Microbiol, Changsha 410208, Hunan, Peoples R China.
通讯机构：
[Lu, Fangguo] H;Hunan Univ Chinese Med, Med Sch, Dept Microbiol, Changsha 410208, Hunan, Peoples R China.
关键词：
Aptamer;SELEX;Aptasensor;Targeted drug delivery;Nucleic acid therapeutics
摘要：
Aptamers are single-stranded nucleic acid sequences that can bind to target molecules with high selectivity and affinity. Most aptamers are screened in vitro by a combinatorial biology technique called systematic evolution of ligands by exponential enrichment (SELEX). Since aptamers were discovered in the 1990s, they have attracted considerable attention and have been widely used in many fields owing to their unique advantages. In this review, we present an overview of the advancements made in aptamers used for biosensors and targeted therapy. For the former, we will discuss multiple aptamer-based biosensors with different principles detected by various signaling methods. For the latter, we will focus on aptamer-based targeted therapy using aptamers as both biotechnological tools for targeted drug delivery and as targeted therapeutic agents. Finally, challenges and new perspectives associated with these two regions were further discussed. We hope that this review will help researchers interested in aptamer-related biosensing and targeted therapy research.
摘要：
A highly sensitive and selective fluorometric method is described for determination of mercury(II). It is based on (a) the use of graphene oxide (GO) acting as a quencher of the fluoresence of the carboxy-fluorescein (FAM), and (b) of Hg(II)-triggered cleavage of the newly formed nucleic acid sequences harbored blunt 3'-hydroxyl termini by exonuclease III (Exo III) that leads to signal amplification. Two DNA probes are used, viz. a capture probe (CP) and a help probe; HP) that is partially complementary. In the absence of Hg(II), the FAM-labeled hairpin (signal probe, SP) is adsorbed onto the surface of GO via pi-stacking interactions. CP blocks the release of the HP for binding to SP. This results in quenching of the green fluorescence of the label. Upon addition of Hg(II), the linear structure of CP is converted to a hairpin structure due to the formation of thymidine-Hg(II)-thymidine duplexes. HP is released from the CP/HP hybrids, and this causes SP to be released from from GO and fluorescence to be recovered. The signal is strongly amplified by using Exo III-assisted targeting and recycling of HP. Hence, Hg(II) can be detected via the strong increase in fluorescence. The method has a linear response in the 0.1 to 30 nM Hg(II) concentration range and a 10 pM detection limit. It was applied to the determination of Hg(II) in three (spiked) Chinese medicines. Graphical abstract Schematic representation of fluorescence sensing strategy for Hg(2+) by using graphene oxide as a quencher and exonuclease III-assisted signal amplification.
作者机构：
[李玲] College of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Changsha, 410208, China;[卢芳国; 张波; 高强; 胡珏] Medical College, Hunan University of Chinese Medicine, Changsha, 410208, China;[蔡亮] Microbiology Lab, Hunan Provincial Center for Disease Control and Prevention, Changsha, 410000, China;[吴涛; 何谷良] Graduate School, Hunan University of Chinese Medicine, Changsha, 410208, China
